Class 9

You can Download Excretion to Maintain Homeostasis Questions and Answers, Summary, Activity, Notes, Kerala Syllabus 9th Standard Biology Solutions Part 2 Chapter 5 help you to revise complete Syllabus and score more marks in your examinations.

Kerala State Syllabus 9th Standard Biology Solutions Chapter 5 Excretion to Maintain Homeostasis

Excretion to Maintain Homeostasis Textual Questions and Answers

Excretion To Maintain Homeostasis Kerala Syllabus 9th Question 1.
How can make our external environment garbage-free?
Answer:
We can made our external environment garbage free by processing reusing or recycling waste material.

Kerala Syllabus 9th Standard Biology Notes Chapter 5 Question 2.
Different by-products are formed as a result of many …. in the cells.
Answer:
Metabolic activities

Excretion To Maintain Homeostasis Notes Kerala Syllabus Question 3.
What are the main excretory products in human beings?
Answer:
Carbon dioxide, water, and nitrogenous compounds.

Kerala Syllabus 9th Standard Biology Notes Question 4.
………. carries excretory products to excretory compounds.
Answer:
Blood

9th Class Biology Chapter 5 Notes Kerala Syllabus Question 5.
Complete the flow chart of the waste materials formed inside the cells reach excretory organs?

Answer:
a) Tissue fluid
b) Blood

Excretory Organs

9th Standard Biology Notes Kerala Syllabus Question 6.
Name the organs that help to remove waste materials from blood and maintain homeostasis?
Answer:
Liver, Lungs, skin, and kidney

9th Class Biology 5th Lesson Questions And Answers Question 7.
Complete the illustration.

Answer:

Liver – The Waste Processing Unit

Hsslive Guru Class 9 Biology Kerala Syllabus Question 8.
What is the function of liver?
Answer:
Liver converts harmful substances entering the body and those produced inside the body into harmless substances. Synthesis of urea from ammonia is an example for this.

Hss Live Guru 9 Biology Kerala Syllabus Question 9.
…………….. are formed by the breakdown of protein.
Answer:
Amino acids

Kerala Syllabus 9th Standard Biology Solutions Question 10.
What are the uses of amino acids?
Answer:
Amino acids are used for the synthesis of various substances like proteins, enzymes etc. which are used for bodybuilding.

Class 9 Biology Solutions Kerala Syllabus Question 11.
What is the most harmful by-product formed by the metabolism of amino acid?
Answer:
Ammonia

9th Class Biology Chapter 5 Kerala Syllabus Question 12.
Prepare a note on the synthesis of urea.
Answer:
Amino acids are formed by the breakdown of proteins. As a result of the metabolic activities of amino acids, several nitrogenous by-products are formed. The most harmful among these is ammonia. The ammonia formed in tissues diffuses into blood through tissue fluids and blood transports it to the liver. In liver with the help of certain enzymes, ammonia combines with carbon dioxide and water to form urea.

Kerala Syllabus 9th Class Biology Notes Question 13.
Write down the chemical equation of the synthesis of urea.
Ammonia + carbon dioxide + water → urea

Formation Of Sweat

Hsslive Guru 9th Biology Kerala Syllabus Question 14.
How is sweat formed from blood?
Answer:
Blood passes through the capillaries excess water and minerals enter the sweat glands. This is eliminated as sweat through the body surface.

9th Biology Notes Kerala Syllabus Question 15.
What are the components of sweat?
Answer:
Urea, salt, and water

Biology 9th Class Chapter 5 Notes Kerala Syllabus Question 16.
Which is the largest organ in our body?
Answer:
Skin

Kerala Syllabus 9th Biology Notes Question 17.
What do you mean by sweat gland?
Answer:
Sweat gland is a long coiled tube that opens to the surface of the skin.

Kerala Syllabus 9th Standard Biology Guide Question 18.
The lower portion of the sweat gland is rich in
Answer:
Capillaries

Hsslive Guru Biology 9th Kerala Syllabus Question 19.
……… helps in regulating our body temperature.
Answer:
Sweating

Kidneys

Hsslive Guru 9 Biology Kerala Syllabus Question 20.
What are the main functions of kidney?
Answer:
Kidneys are vital organs which help in maintaining homeostasis by filtering waste products like urea, salts, vitamins, other harmful substances, etc. from blood. When blood passes through the kidneys, the waste materials present in it are filtered.

Question 21.
Prepare a short note on the position and size of the kidney?
Answer:
Human beings possess a pair of kidneys, situated on both sides of the vertebral column adjoining the muscles in the abdominal cavity. They are bean-shaped and are about 11 cm long, 5 cm broad and 3 cm thick. Each kidney is covered by a strong but soft membrane.

Question 22.
Illustrate kidney and its parts.
Answer:

Question 23.
Complete the illustration of kidneys and associated parts.

Answer:
a) bean-shaped and are located in the abdominal cavity on either side of the vertebral column.
b) Renal artery
c) Renal vein
d) Ureters

Internal Structure of Kidney

Question 24.
Internal structure of kidney
Answer:

Question 25.
Analyze illustration given below and prepare table including the parts and peculiarities of nephron.

Answer:

Question 26.
……… are the structural and functional units of kidneys.
Answer:
Nephrons

Question 27.
Where is Bowmann’s Capsule of nephrons distributed?
Answer:
Cortex

Question 28.
What is capsular space?
Answer:
It is the space between the double walls of the Bowman’s capsule.

Question 29.
Blood capillaries seen around the renal tubules as continuation of the efferent vessel are ………..
Answer:
Peritubular capillaries

Question 30.
………… helps the ultrafiltration.
Answer:
Glomerulus

Formation of urine

Question 31.
List out the process of formation of urine.
Answer:

• Ultrafiltration
• Reabsorption and secretion
• Absorption of water

Question 32.
What are the characteristic that help in ultrafiltration?
Answer:
This process is supported by the high pressure developed in the glomerulus, due to the difference in the diameter of afferent vessel and efferent vessel

Question 33.
How is urine formed?
Answer:
When blood flows through the glomerulus, ultrafiltration takes place through its small pores. The glomerular filtrate formed as a result of this is collected in the capsular space. When glomerular filtrate flows through renal tubeless to the collecting duct, essential components are reabsorbed to the peritubular capillaries. The absorption of excess water from the glomerular filtrate takes place in the collecting duct. What is left behind is urine.

Question 34.
Prepare a table relating to the different components of the glomerular filtrate and urine.
Answer:

Question 35.
Urine is temporarily stored in the
Answer:
Urinary bladder

Question 36.
State whether true or false
Washing out of germs inside the urinary tract also
takes place during the process of micturition.
Answer:
True

Question 37.
How does avoiding timely urination affect our body and list out the healthy habits to be followed?
Answer:
Avoiding urination for a long time prevents the expulsion of bacteria that may be present in the urinary tract and urinary bladder. This causes infection in the inner membrane of the urinary bladder.
Females are more susceptible to urinary tract infections when compared to males.
1) Frequent urination
2) Drink plenty of water
3) Keep the personal hygiene

Question 38.
Prepare a flow chart on the role of kidneys in maintaining homeostasis
Answer:

Kidney Diseases

Haemodialysis

Question 39.
What do you mean by hemodialysis?
Answer:
Haemodialysis is the process proposed by modern medicine for the removal of wastes from the blood when both the kidneys become non-functional. In this process, blood is pumped into an artificial kidney called haemodialyser and is purified.

Question 40.
Who designed the first artificial kidney?
Answer:
William Johann Kolff in 1944.

Kidney Transplantation

When both kidneys of an individual get damaged completely a fully functioning kidney should be received from a donor to save life. Kidney of a healthy person who died in an accident or of a completely healthy person can be transplanted after considering the matching of blood groups and tissues.

Excretion In Other Organisms

Diversity in Excretion:

Question 41.
Prepare a table about the excretory organs and excretory products of different organisms?

Answer:

Question 42.
What are the methods of the excretion in plants?
Answer:
Stomata, hydathodes, formation of heartwood, abscision of leaves.

Question 43.
Illustration related to the excretion in plants.
Answer:

Let Us Assess

Question 1.
Glucose, amino acids, etc. found in the glomerular filtrate are absent in urine. Why?
Answer:
When glomerular filtrate flows through renal tubules to the collecting duct, essential components are reabsorbed to the peritubular capillaries. So glucose and amino acids are absent in urine.

Question 2.
The steps involved in the formation of urine are given below. Arrange them in the correct sequence.
1. Collects urine
2. Ultrafiltration takes place
3. Reabsorption of ions takes place towards this part from renal tubules.
4. Collects glomerular filtrate
5. Excess urea is secreted here from peritubular capillaries.

Answer:

Question 3.
Alcoholism is a bad habit which should be avoided. Analyze this statement relating it to the health of liver.
Answer:
The detoxification of alcohol in our body is done by liver cells. As a result liver cell become damaged.

Question 4.
Based on the similarities in major excretory materials, arrange the following organisms properly in the table given below
Frog, Amoeba, Human beings, Fish, Birds, Insects

Answer:

Question 5.
Observe the figure and answer the questions.

Answer:
a) A) Afferent vessel
B) Efferent vessel
b) When blood flows through the glomerulus, ultrafiltration takes place through its small pores. This process is supported by the high pressure developed.in the glomerulus, due to the difference in the diameters of afferent versel and efferent vessel.

You can Download Motion and Laws of Motion Questions and Answers, Summary, Activity, Notes, Kerala Syllabus 9th Standard Physics Solutions Part 1 Chapter 3 help you to revise complete Syllabus and score more marks in your examinations.

Kerala State Syllabus 9th Standard Physics Solutions Chapter 3 Motion and Laws of Motion

Motion and Laws of Motion Textual Questions and Answers

Kerala Syllabus 9th Standard Physics Notes Chapter 3 Question 1.
What will be the result when a man tries to move a vehicle by pushing it, standing inside the vehicle? The vehicle moves/the vehicle doesn’t move.
Answer:
The vehicle doesn’t move.

Motion And Laws Of Motion Class 9 Kerala Syllabus Question 2.
What if the same vehicle is pushed from outside.
Answer:
Yes, the vehicle moves
Internal forces can not move an object, but only an external unbalanced force can cause motion.

Newton’S First Law Of Motion

Every object continues in its state of rest or of uniform motion along a straight line unless an unbalanced external force acts on it. This is Newton’s First law of motion.

Class 9 Physics Chapter 3 Kerala Syllabus Question 3.
What is inertia of rest?
Answer:
Inertia of rest is the tendency of a body to remain in its state of rest or its inability to change its state of rest by itself.

Class 9 Physics Chapter 3 Notes Kerala Syllabus Question 4.
Write down an activity to show inertia of rest.

Answer:
Place a bottle filled with water on a thick rough pa¬per as shown. Pull the paper suddenly to one side. The bottle falls in the opposite direction fo the motion of paper. This is because of inertia of rest.

Kerala Syllabus 9th Standard Physics Chapter 3 Question 5.
What is inertia of motion?
Answer:
Inertia of motion is defined as the inability of a body to change it state of motion by itself.

9th Class Physics Notes Chapter 3 Kerala Syllabus Question 6.
Write down an activity to show inertia of motion.

Answer:
Place a bottle on a thick paper with rough surface. Bring the bottle into motion by pulling the paper slowly. Gradually increase the speed of pulling stop pulling when the bottle gains a certain speed. The bottle falls in the direction of motion of the pa-per, due to inertia of motion of the bottle.

9th Physics Chapter 3 Notes Kerala Syllabus Question 7.
Find out reasons for the Situations
a) Place some carom board coins in a pile. Using the striker, strike out the coin at the bottom. What do you observe? What is the reason?
b) When a running bus is suddenly stopped, passengers, standing in the bus show a tendency to fall forward.
c) Place a small brick on a plank. When the plank
is pulled suddenly the brick remains in the same position as before.
d) When a bus moves forward suddenly from rest, the standing passengers tend to fall backward.
e) Accidents that happen to passengers who do not wear seat belts are more fatal.
Answer:
a) Only the coin at the bottom is thrown away. Others will remain in the previous stage.
b) The passengers start to move forward due to the tendency to continue in its state of motion.
c) It is due to the tendency to continue in the state of rest.
d) The passengers tend to fall backward due to the tendency to continue in their state of rest.
e) The passengers inside the vehicle have the tendency to move forward due to inertia of motion.
Inertia: The inability of a body to change its state of rest or of uniform motion along a straight line by its itself.
Inertia of rest: Inertia of rest is defined as the inability of a body to change its state of rest by itself.
Inertia of motion : Inertia of motion is defined as the inability of a body to change its state of motion by itself. Eg. When a running bus is suddenly stopped, the standing passengers fall forward due to inertia of motion. When a bus at rest starts suddenly, the standing passengers fall backward due to inertia of rest.

9th Class Physics Chapter 3 Kerala Syllabus Question 8.
Expand the table by finding more situations from daily life.

Answer:

Physics Class 9 Chapter 3 Kerala Syllabus Question 9.
Find out the reasons
a) An athlete doing a long jump-start his run from a distance.
b) A running elephant cannot change its direction suddenly.
Answer:
a) This activity helps to cover long distances by utilizing inertia of motion.
b) Mass of elephant is greater. So inertia of motion also be greater. Also, it cannot be able to change its direction suddenly.

Mass And Inertia

9th Class Physics 3rd Chapter Kerala Syllabus Question 10.
It is dangerous for loaded vehicles to negotiate a curve in the road without reducing speed. What is the reason?
Answer:
Loaded vehicles possess more inertia of motion. As ” mass increases, inertia also increases.

9th Class Physics Chapter 3 Notes Kerala Syllabus Question 11.
It is more difficult to roll a filled tar drum than an empty drum.
a) Which of two has a greater mass?
b) Which has greater inertia?
Answer:
a) The mass of drum filled with tar will be greater,
b) Inertia will be greater to tar filled drum
Conclusion: Inertia depends on mass. When the mass increases inertia also increases. When the mass decreases inertia also decreases.

Physics Class 9 Chapter 3 Questions And Answers Question 12.
If a tennis ball (mass 58.5 g) and a cricket ball (mass 163 g) are the reach a certain distance when hit with a cricket bat, which is to be hit with greater force? The tennis ball / the cricket ball?
Answer:
The cricket ball

9th Class Physics Notes Kerala Syllabus  Question 13.
Will the change of velocity be the same in both the cases?
Answer:
Velocities are different in both cases due to the difference in masses.

The inertia of an object depends upon its mass. When the mass increases, inertia also increases.

Momentum

Momentum is a characteristic property of moving objects. It is measured as the product of the mass of the body and its velocity.

Momentum = mass × velocity
Unit of momentum is kg m/s

Chapter 3 Physics Class 9 Kerala Syllabus Question 14.
A car of 1000 kg moves with a velocity of 10 m/s. On applying brakes it comes to rest in 5s. Then what are its initial momentum and final momentum?
Answer:
m = 1000 kg
u = 10 m/s
v = 0
t = 5s
Initial momentum = mu
= 1000 × 10 =10000 kg m/s
Final momentum = mV
= 1000 × 0 = 0 Kg m/s

Physics Chapter 3 Class 9 Kerala Syllabus Question 15.
A hockey ball of mass 200 g hits on a hockey stick with a velocity 10 m/s. Calculate the change in momentum if the ball bounces back on the same path with the same speed.
Answer:
m = 200g = 200/1000 = 0.2 kg
Initial momentum = mu
= 0.2 × 10 = 2 kg m/s
Final momentum = mv
= 0.2 × 70 = 2 kgm/s
change in momentum = mv – mv = – 2 – 2
= -4 kg m/s

Class 9 Physics Chapter 3 Kerala Syllabus Question 16.
A loaded lorry of mass 12000 kg moves with a velocity of 12 m/s. Its velocity becomes 10 m/s after 5 s.
a) What is the initial momentum and what is the final momentum?
b) What is the change in momentum?
c) What is the rate of change of momentum?
Answer:
a) Initial momentum = mu
=12000 × 12 = 144000 kg m/s Final momentum = mv
=12000 × 10 = 120000 kg m/s
b) Change in momentum = mv – mu
= 120000 – 144000 = –24000 kg m/s
c) Rate of change in momentum = \(\frac { mv – mu }{ t }\)
= \(\frac { -24000 }{ 5 }\)
= – 4800 kgm/s²

Newton’S Second Law Of Motion

The rate of change of momentum of a body is directly proportional to the unbalanced external force acting on it.

Equation for Calculating Force:
According to second law of motion F ∝ ma
F = kma (k – a constant)
k = 1 ∴ F = 1 × ma
F = ma,

ie. F- Force, m – mass, a – acceleration.
Unit of force is Newton (N)
Another unit is dyne.

Physics 9th Class Chapter 3 Kerala Syllabus Question 17.
A constant force is applied for 2 s on a body of mass 5 kg. As a result, if the velocity of the body is changed from 3 m/s to 7 m/s, find out the value of the applied force.
Answer:

Physics Class 9 Chapter 3 Notes Kerala Syllabus Question 18.
A car moving with a speed of 108 km/h comes to rest after 4s on applying brake, if the mass of the car including the passengers is 1000 kg, what will be the force applied when brake is applied?
Answer:
Initial velocity of the car u = 108 km/h

= 30 m/s
Final velocity v = 0
Mass m = 1000 kg
Time t = 4s
According to newton’s second law
F = ma

= – 7500 N
The negative sign indicates that the applied force is opposite to the direction of motion.

Question 19.
Velocity of an object of mass 5 kg increases from 3 m/s to 7 m/s on applying a force continuously for 2s. Find out the force applied. If the duration for which force acts is extended to 5s, what will be the velocity of the object then?
Answer:
u = 3 m/s
v = 7 m/s
t = 2s
m = 5 kg
According to Second Law of Motion F = ma

If we substitute the values in the equation v = u + at, velocity can be calcualted when the time for force is extended to 5s.
v = 3 + (2 × 5) = 13 m/s

Question 20.
Velocity-time graph of an object of mass 20 g, moving along the surface of a long table is given below.

What is the frictional force experienced by the object?
Answer:
From the graph
Initial velocity u = 20 m/s
Final velocity v = 0m/s
t = 10 s
m = 20
g = 20/100 kg
F = ma

= -0.04 N
The negative sign shows that the frictional force is acting opposite to the direction of motion of the object.

Question 21.
m₁ and m₂ are the masses of two bodies. When a force of 5 N is applied on each body, m₁ gets an acceleration of 10 m/s² and m₂, 20 m/s². If the two bodies are tied together and the same force is applied, find the acceleration of the combined system.
Answer:

Impulse

Impulsive force is a very large force acting for a very short time.
Impulse of force is the product of the force and the time.
Impulse = Force × time
Impulse – Momentum Principle
According to Newton’s second law of motion,
\(F=\frac{m(v-u)}{t}\)
F x t = m(v – u)
F × t= mv – mu
ie. impulse = change Is momentum This is known as impulse-momentum principle. It states that a change in momentum of an object is equal to the impulse experienced by it.

Question 22.
Explain the following situation by relating force and time.
Answer:
When the change in momentum is a constant, the force acting on a body will be inversely proportional to the time taken. As time increase, the force acting decreases and as time decreases, the force acting increases.

Question 23.
During a pole vault jump, the impact is reduced by falling on a foam bed.
Answer:
When the change in momentum is a constant, the force acting on a body will be inversely proportional to the time taken. As time increase, the force acting decreases and as time decreases, the force acting increases.

Question 24.
Hay or sponges are used while packing glassware. This helps to avoid breaking of glasswares due to collision.
Answer:
When the change in momentum is a constant, the force acting on a body will be inversely proportional to the time taken. As time increase, the force acting decreases and as time decreases, the force acting increases.

Question 25.
Karate experts move their hands with great speed to chop strong bricks.
Answer:
When the change in momentum is a constant, the force acting on a body will be inversely proportional to the time taken. As time increase, the force acting decreases and as time decreases, the force acting increases.

Newton’S Third Law Of Motion

Pass a long string through a straw and tie the string between two windows of the classroom Paste an inflated balloon on the straw.

Question 26.
Inflate a balloon and release it suddenly. What happens?
Answer:
Release of air causes the balloon to move in the opposite direction. Releasing air from the balloon is action and the movement of the balloon is reaction.

Question 27.
What do you observe?
Answer:
The cork pushed out due to the pressure of steam. The tube moves backward.

Question 28.
If the action is the cork being pushed out due to the force exerted by the steam on it, what is the reaction?
Answer:
The reaction is the backward movement of boiling tube.

Question 29.
Write down the action and reaction while we are walking on a floor?
Answer:
When we are walking through a floor, we applies a force on the floor. This is action. The floor applies a force in the opposite direction. This is reaction.
Rocket Propulsion:

• Escaping of hot gases from the jet of rocket is action.
• The force exerted by these gases on the rocket is reaction.

Question 30.
Are the action and reaction equal and opposite?
Answer:
Action and reaction are equal and opposite.
Newton’s Third law of Motion For every action there is an equal and opposite reaction.

Question 31.
Examine the following situations and complete the table.

Answer:

Conclusions:

• As a result of the applied force by a second body to a body, reaction will occur at the second body.
• Action and reaction are equal and opposite.
• Since action and reaction takes place in two different bodies, they do not cancel each other.

Law Of Conservation Of Momentum

Observe the figure and answer the following questions.

Question 32.
Move the first marble slightly back and roll forward. What happens?
Answer:
One marble will be thrown off from the other end and reaches the previous position.

Question 33.
Bring the two marbles into contact and let them roll. What happens?
Answer:
Two marbles will move from the other end.

Observe the figure and answer the following questions.

Question 34.
Total momentum before collision = ………….
ANswer:
m₁ u₁ + m₂ u₂.

Question 35.
Total momentum after collision =…….
Answer:
m₁ v₁ + m₂ v₂

Question 36.
Initial momentum of A=
Answer:
m₁ u₁

Question 37.
Final momentum of A =
Answer:
m₁ v₁

Question 38.
Change in momentum of A=
Answer:
m₁ v₁ – m₁ u₁

Question 39.
Rate of change of momentum of A =
Answer:
\(\frac{m_{1} v_{1}-m_{1} u_{1}}{t}\)

Question 40.
Initial momentum of B =……
Answer:
m₂ u₂

Question 41.
Final momentum of = …………….
Answer:
m₂ v₂

Question 42.
Change in momentum of B = ………
Answer:
m₂ v₂ – m₂ u₂.

Question 43.
Rate of change of momentum of B = ……………
Answer:
\(\frac{\mathrm{m}_{2} \mathrm{v}_{2}-\mathrm{m}_{2} \mathrm{u}_{2}}{\mathrm{t}}\)

According to IInd Law of motion, rate of change of momentum is directly proportional to the external force.
Force exerted by B on A

Law Of Conservation Of Momentum

In the absence of an external force, the total momentum of a system is a constant.

Question 44.
A bullet is fired with a velocity v from a gun of mass M. What will be the recoil velocity of the gun if the mass of the bullet is m?
Answer:
According to low of Conservation of Momentum, total momentum ofthe gun and the bullet before firing and their total momentum after firing will be equal,
ie. Total momentum before firing = 0 + 0 =0
Total momentum after firing = MV + mv
Accoriding to Law of Conservation of Momentum 0 =MV + mv
MV = -mv
V = \(\frac { -mv }{ M }\)
The recoil velocity ofthe gun V = \(\frac { -mv }{ M }\). The negative
sign indicates that the gun moves in the opposite direction of motion ofthe bullet.

Question 45.
Suppose a child of mass 40 kg running on a horizontal surface with a velocity of 5m/s jumps on a stationary skating board of mass3 kg while running as shown in the figure. If there is no other force acting horizontally (assuming the frictional force on the wheels to be zero), calculate the velocity of the combined system of child and the skating board.
Answer:
Suppose the velocity of the board while moving is u. Total momentum of the child and the skating board before jumping will be
= 40 kg × 5 m/s + 3 kg × 0 m/s
= 200 kg m/s Total momentum when the system starts moving (body and skating board)
= (40 + 3) kg × u m/s
= 43 × u kgm/s.
According to the Law of Conservation of Momentum, Total momentum remains constant.
43 u = 200
u = 200/43 = + 4.65 m/s

Circular Motion

Motion of a body through a circular path is known as circular motion.

Question 46.
Does the velocity of an object moving with a uniform speed along a circular path change?
Yes

Question 47.
How does this change in velocity happen?
Due to change in speed/change in direction/due to change in both speed and direction.
Answer:
Due to change in direction.

• Whirling of a stone tied to a string is a type of circular motion.
• The force we apply form the center of the circle reaches the object through the string. The acceleration which a body in circular motion experiences towards the center of the circle through the radius is centripetal acceleration. The force that creates centripetal acceleration is a centripetal force.
  Centripetal force (Fc) = mv²/t
  m – mass, v-velocity, r- radius of the circular path
• In the absence of centripetal force, circular moving body thrown off through the tangent.
• If a body moving along a circular path covers equal distances in equal intervals of time, it is said to be in uniform circular motion.

Question 48.
In hammer throw, before the hammer is let go off, why is it whirled around along a circular path?
Answer:
It is to get initial momentum. Also helpful to cover long distances through the tangent.

Question 49.
How does the speed of a giant wheel in an amusement park?
Answer:
The motion of giant wheel is controlled by mechanically. So its speed is uniform except when starting and stopping.
Examples for uniform circular motion:

• Motion of needles in a watch.
• Whirling of a stone tied to a string.
• Movement of the leaf of an electric fan except when starting and stopping.
• Circular motion of earth’s artificial /satellites.

The acceleration experienced by an object in a circular motion, along the radius, towards the center of the circle, is known as centripetal acceleration. The force that creates a centripetal acceleration is called centripetal force. Centripetal acceleration and centripetal force are directed towards the center.
If an object moving along a circular path covers equal distances in equal intervals of time, it is said to be in uniform circular motion.

Let Us Assess

Question 1.
Observe the figures given below. Answer the following questions.

a) When the card is suddenly struck off, what happens to the coin? Explain.
b) What is the law to which this property is related?
c) How is this property related to the mass of the object?
Answer:
a) The coin falls into the glass due to inertia of rest.
b) Newton’s 1st law of motion.
c) Mass increases inertia increases.

Question 2.
What are the balanced forces acting on a book at rest on a table?
Answer:
a) Downward force exerts by the book on the table (i.e., weight of the book).
b) Upward force applies by the table on the book (reaction).

Question 3.
To remove the dust from a carpet, it is suspended and hit with a stick. What is the scientific principle behind it?
Answer:
Inertia of rest. The dust in the carpet shows the tendency to continue in its state of rest.

Question 4.
Acar and a bus are traveling with the same velocity. Which has greater momentum? Why?
Answer:
Bus. Because when mass increases momentum increases.

Question 5.
On the basis of Newton’s third law of motion, explain the source of force that helps to propel a rocket upward.
Answer:

• It is due to the reaction force by the escaping gas from rocket.
• Escaping gases form the rocket is action.
• The force exerted by escaping gases on the rocket is reaction.

Question 6.
A car-travels with a velocity of 15 m/s. The total mass of the car and the passengers in it is 1000 kg. Find the momentum of the car.
Answer:
Momentum p = mv
= 1000 × 15
= 15000 kg m/s

Question 7.
Give reasons:
a) When a bullet is fired from a gun, the gun recoils.
b) When a bus at rest suddenly moves forward, the passengers, standing in the bus, fall backward.
c) We slip on a mossy surface.
Answer:
a) The gun recoils due to the reaction force applied by the shot to the gun. Forward movement of the shot is action and the Backward movement of the gun is reaction.
b) Inertia of rest is the reason. The passengers tends continue in state of rest.
c) Absence of reaction force is the cause for this.

Extended Activities

Question 1.
Prepare and present an experiment to illustrate inertia of rest.
Answer:
Make a pile of coins on a table. Strikes off the lowest coin by a knife quickly. Only that particular coin thrown off and the others remains in the previous manner. This is due to the tendency of coins to remain in its state of rest.

Question 2.
Find out situations from our daily life to explain the law of conservation of momentum and note them down.
Answer:

• Recoil of a gun during firing.
• Rocket propulsion.
• Bomb explosion.

Motion and Laws of Motion More Questions and Answers

Question 1.
Fill in the blanks.
a) As the time interval decreases, rate of change of momentum
b) The force required to produce an acceleration of 1 m/s² on a body of mass 1 kg is
Answer:
a) Increases
b) 1 Newton (1N)

Question 2.
Correct the statement if any wrong.
An object moving with uniform speed along a circular path undergoes velocity change due to the change in speed.
Answer:
An object moving with a uniform speed along a circular path undergoes velocity change due to change in direction.

Question 4.
a) What is meant by momentum?
b) Write down the equation for calculating momentum.
c) A body of mass 50 kg starts from rest. If its velocity changes to 15 m/s after 10 seconds, calculate the change in momentum? What will be the rate of change of momentum?
Answer:
a) The measurement of the quantity of motion of a body is called momentum
b) Momentum p = mv

Question 5.
a) Define circular motion and uniform circular motion.
b) What is the relation between centripetal force and centripetal acceleration?
Answer:
a) The motion of an object through a circular path is said to be circular motion.
If an object moving along a circular path covers equal distance in equal intervals of time if is said to be uniform circular motion.
b) The force requires to produce centripetal acceleration is centripetal force.

Question 6.
a) State Newton’s II law of motion?
b) Derive the equation for force on the basis of this law.
Answer:
a) The rate of change of momentum of a body is directly proportional to the unbalanced external force acting on it.
b) According to II law.

F = kma (k – a constant)
The force required to produce an acceleration of 1 m/s² on a body of mass 1 kg is 1N
1 = k × 1 × 1
k = 1
∴ F = 1 × ma
F = ma

Question 7.
A car of mass 1000 kg runs with a velocity of 10 m/s. What is the momentum of this car?
Answer:
Momentum p = mv
m = 1000 kg
v = 10 m/s
∴ P = 1000 × 10
= 10000 kg m/s

Question 8.
A loaded lorry of mass 1500 kg moves with a velocity of 12 m/s. Within a small interval of the time, the velocity becomes 10 m/s.
a) What is the initial momentum of the lorry?
b) What is its final momentum?
c) What is the change in momentum?
Answer:
a) Initial momentum P = mv, m = 1500 kg
= 1500 × 12, v₁ = 12m/s
= 18000 kg m/s, v₂ = 10 m/s
b) Final momentum p = mv₂
= 1500 × 10 = 15000 kg m/s
c) Change in momentum = mv₂ – mv₁
=15000 – 18000
= – 3000 kg m/s
Rate of change of momentum
= \(\frac { change in momentum }{ Time }\)
= \(\frac { m(v – u) }{ t }\)

You can Download Wave Motion Questions and Answers, Summary, Activity, Notes, Kerala Syllabus 9th Standard Chemistry Solutions Part 2 Chapter 5 help you to revise complete Syllabus and score more marks in your examinations.

Kerala State Syllabus 9th Standard Chemistry Solutions Chapter 5 Acids, Bases, Salts

Acids, Bases, Salts Textual Questions and Answers

Learning Activities

hss live guru 9th chemistry Acids, Bases, Salts Question 1.
What are the methods used to identify acids and alkalies
Answer:
Using indicators like litmus, phenolphthalein and methyl orange.

kerala syllabus 9th standard chemistry chapter 5 Acids, Bases, Salts Question 2.
Find the characteristics of the substances given in the table below using litmus papers.

Answer:

class 9 chemistry chapter 5 kerala syllabus Acids, Bases, Salts Question 3.
Take a small piece of zinc in a test tube as shown in the figure. Add 2ml of dilute hydrochloric acid using a dropper. Show a burning match stick at the mouth of the test tube. Record the observation.

Answer:
Burn with a ‘pop’ sound

kerala syllabus 9th standard chemistry notes Acids, Bases, Salts Question 4.
What would be the reason?
Answer:
Hydrogen gas liberated burns

kerala syllabus 9th standard chemistry notes chapter 5 Question 5.
Now complete the chemical equation of this reaction
Zn + 2HCl → ZnCl₂ + …………..
Answer:
Zn + 2HCl → ZnCl₂ + H₂
Acids react with reactive metals to form hydrogen gas

class 9 chemistry chapter 5 notes kerala syllabus Question 6.
Take some calcium carbonate (marble pieces) in a boiling tube as shown in figure. Add dilute hydro¬chloric acid to it through a thistle funnel. Pass the evolving gas through clear lime water taken in a test tube.

Which is the gas that comes out through the delivery tube?
Answer:
Carbon dioxide

class 9 chemistry chapter 5 notes Acids, Bases, Salts Ques 7.
What is your observation when this gas is passed through clear lime water?
Answer:
LimeWater turns milky
When acids react with carbonates, carbondioxide(CO₂) gas is liberated.

9th class chemistry chapter 5 Acids, Bases, Salts Question 8.
From the characteristics given below, find out those suitable for acids and put (✓) Mark.
1. Have alkaline taste.
2. Turn blue litmus red
3. React with carbonates to form carbon dioxide gas
4. Soapy to touch
5. Liberate hydrogen on reaction with highly reactive metals like Mg and Zn
6. Have sour taste
7. Turns red litmus blue
Answer:

1. Have alkaline taste.
2. Turn blue litmus red (✓)
3. React with carbonates to form carbon dioxide gas (✓)
4. Soapy to touch
5. Liberate hydrogen on reaction with highly reactive metals like Mg and Zn (✓)
6. Have sour taste (✓)
7. Turns red litmus blue

Question 9.
The name of some familiar acids and their chemical formulae are given in the table below. Complete the table.

Answer:

Question 10.
Which component is responsible for the common properties of acids
Answer:
H

Question 11.
Chemical equations showing the formation of oppositely charged ions when hydrochloric acid (HCI) and nitric acid (HN03) dissolve in water are given.
HCI → H⁺+Cl^–
HNO₃ → H⁺+ NO^–
a) Which are the ions present in HCl solution?
b) Which are the ions present in HNO3 solution
c) Which is the ion common to both?
Answer:
a) H⁺ and Cl^–
b) H⁺ and NO₃^–
c) H⁺

Question 12.
What is acids?
Answer:
Acids are substances which can increase the concentration of hydrogen (H⁺) ions in an aqueous solution.

Question 13.
List the acids that are present in lime juice, curd, tamarind, vinegar.
Answer:
Lime juice — Citric acid
Curd — Lactic acid
Tamarind — Tartaric acid
Vinegar — Acetic acid

Question 14.
Write the chemical equation for the ionization of HCl.
Answer:
HCl → H⁺+Cl^–

Ques 15.
How many hydrogen ions are released when one molecule of HCI is ionized?
Answer:
one H⁺

Question 16.
What is the basicity of an acid?
Answer:
The number of hydrogen ions that can be donated by one molecule of an acid is its basicity.
If the basicity is 1, it is called monobasic acid.

Question 17.
Write the ionization equation of nitric acid (HNO3) and find its basicity.
Answer:
HNO₃ → H⁺ +NO^–₃
Basicity -1

Question 18.
Write the chemical equation for the ionization of the sulphuric acid (H2S04)
Answer:
H2SO₄ → H⁺ + HSO^–₄ (bisulphate ion)
HSO^–₄ → H+ + SO^2–₄ (sulphate ion)

Question 19.
How many hydrogen ions are released when one molecule of H₂SO₄ gets ionized? What is its basicity? ’
Answer:
Two H+ ions basicity = 2
It the basicity of an acid is 2,
it is said to be a dibasic acid.

Question 20.
Complete the ionization equation of phosphoric acid (H3PO4).
H₃PO₄ → ………… + PO^3–₄(Phosphate ion)
Answer:
H₃PO₄ → 3H+ + PO^3–₄ (Phosphate ion)

Question 21.
What is the basicity of H₃PO₄?
Answer:
3
If the basicity is 3,
the acid is called a tribasic acid.

Ques 22.
The chemical formulae of some acids are given in the box. Pick out monobasic and dibasic acids.
H₂CO₃, HNO₃, H₃PO₄, H₂SO₃, HCI, H₂SO₄
Answer:
Monobasic: HNO₃, HCI
Dibasic: H₂CO₃, H₂SO₃, H₂SO₄

Question 23.
How do you make soda water? Write the equation of this reaction.
Answer:
CO₂ is dissolved in water to make soda water.
H₂O + CO₂ → H₂CO₃ (Carbonic acid)

Question 24.
Complete the equation of dissolution of SO₂ in water.
………… + ………….. → H₂SO₃ (sulfurous acid)
Answer:
SO₂ + H₂O → H₂SO₃ (sulfurous acid)
CO₂, SO₂ and NO₂ are non-metallic oxides. Generally, compounds formed by the reaction of non-metallic oxides with water are acidic.

Question 25.
What is acid rain?
Answer:
In industrial areas and townships, the chances of air pollution are very high. In such regions, gases like SO₂ and NO₂ reach the atmosphere in larger amounts. These gases dissolve in rainwater and reach the soil as acids. This is known as ‘acid rain’.

Question 26.
What are the environmental problems caused by acid rain?
Answer:

• Plants lose their ability to produce carbohydrates through photosynthesis as their leaves are de- strayed.
• Severe acid rain destroys the greenery of a region.
• The acidic nature of water causes the death and destruction of fish and corals.

Question 27.
What measures are to be taken against the environmental issues caused by acid rain?
Answer:

• Reduce the excessive use of fossil fuels.
• Before using fossil fuels, remove sulfur compounds from them as far as possible.

Question 28.
Burn a neatly rubbed and cleaned magnesium ribbon. Record the observation. What would be the white powder obtained?
Answer:
Magnesium burns brightly and a white powder is formed. The white powder formed is magnesium oxide (MgO)

Question 29.
Take the product in a watch glass and add two or three drops of water. Find its nature using litmus paper.
Answer:
Red litmus turns to blue. MgO is alkaline in nature.

Question 30.
Write the chemical equation of this reaction.
MgO + H₂O → Mg(OH)₂
magnesium hydroxide

Question 31.
Take some water in a beaker, add some quick lime (calcium oxide) and stir it. Take some clear solution in a test tube from the beaker and add a drop of red litmus solution.
a) What do you observe?
b) What is the substance formed when calcium oxide reacts with water? Complete the chemical equation of the reaction.
CaO + H₂O → ……………
c) What do you infer about the nature of this substance from this litmus test?
Answer:
a) The solution turns to blue
b) CaO + H₂O → Ca(OH)₂
c) Ca(OH)₂ is alkaline in nature

Question 32.
Are MgO and CaO metallic oxides or non-metallic oxides?
Answer:
Metallic oxides
Metallic oxides generally exhibit characteristics of bases. The bases that dissolve in water are called alkalies.

Question 33.
From the oxides given below, find out the basic oxides. K₂O, SO₂, P₂O₅, MgO, CaO, NO₂
Answer:
Basic oxides- K₂O, MgO, CaO

Question 34.
Chemical names and formulae of some familiar alkalies are given in the table. Complete the table.

Answer:

Question 35.
Can you find out the common factor in alkalies?
Answer:
OH

Bases and alkalies:
All bases are not alkalies. Water-soluble bases are called alkalies.
NaOH and KOH are alkalies. But even though Al(OH)₃ and Cu(OH). are based, they are not considered as alkalies as they are not soluble in water. Metallic oxides are generally basic in nature. But a few of them have both acidic as well as basic character. Such oxides are called amphoteric oxides. Example Al,O₃, ZnO
They can react with acids as well as bases.

Question 36.
Write the equation of the dissolution of sodium hydroxide in water.
Answer:
NaOH → Na⁺ +OH^– (hydoxide ion)

Question 37.
Complete the given equation of the ionization of calcium hydroxide.
Ca(OH)₂ → Ca⁺₂ +……….
Answer:
Ca(OH)₂→ Ca⁺₂ + 2OH^–

Question 38.
Which is the common ion released when alkalies dissolve in water?
Answer:
OH-
Alkalies are substances which can increase the concentration of hydroxide (OH) ions in anaqueous solution.

Question 39.
Write common names of some alkalies, their chemical names and chemical formulae
Answer:

Question 40.
The equations representing the ionization of some acids and alkalies are given below. Fill in the blanks.
Answer:
HCl → H⁺ + Cl^–
KOH → K⁺ +OH^–
H₂CO₃ → 2H⁺ + CO₃^2-
NH₄OH → NH⁺₄ + OH^–
HNO₃ → H⁺ + NO^–₃

Question 41.
What is Arrhenius theory?
Answer:
According to Arrhenius theory, acids are substances which liberate H+ ions in aqueous solution and bases are substances which liberate OH- ions in aqueous solutions.

Question 42.
What was the color of NaOH solution when phenolphthalein was added?
Answer:
Pink

Question 43.
Which nature of the NaOH solution is indicated here?
Answer:
Alkaline

Question 44.
What do you infer from the decrease in the intensity of colour of the NaOH solution on adding HCl?
Answer:
Concentration of NaOH is decreasing

Question 45.
When the color disappears completely will there be any NaOH left behind in the conical flask?
Answer:
No

Question 46.
Add a few drops of NaOH solution to the completely decolorized. What change can you observe? What will be the reason?
Answer:
Pink color reappears concentration of NaOH in-creases.

Question 47.
To this again add dilute HCl drop by drop and stir it. What do you observe?
Answer:
Pink color disappears

Question 48.
What are neutralization reactions?
Answer:
Acid and alkali react with each other to nullify their individual properties. Such chemical reactions are called neutralization reactions.

Question 49.
Write the chemical equation for the neutralization reaction between sodium hydroxide and dilute hydrochloric acid.
Answer:
NaOH + HCI → NaCI + H₂O

Question 50.
You have already recorded the volume of HCI used for neutralization of 20 mL NaOH in the earlier experiment. Change the concentration of the acid and repeat the experiment. Is there any change in the volume of HCI?
Answer:
Yes

Question 51.
Can you find out more examples for neutralization reaction?
Answer:

• Slaked lime is sprinkled in farms to reduce acidity
• Antacids are used to remove acidity in the stom¬ach.

Question 52.
What happens when the acid level in the stomach is high?
Answer:
It increases the acidity of the stomach

Question 53.
What do we do in such situations?
Answer:
We take antacids.

Question 54.
What are antacids?
Answer:
The medicines used for reducing acidity in the stomach are known as antacids.

Question 55.
What types of substances are present in antacids?
Answer:
Alkaline

Question 56.
How do they work?
Answer:
They neutralize acid in the stomach.

Question 57.
Take equal quantities of dilute hydrochloric acid, sodium hydroxide solution and distilled water in three test tubes. Use red litmus paper and blue litmus paper to find out the nature of the solutions. Also, add two or three drops of phenolphthalein solution to the three test tubes. Record the observation and find out the nature of the substances.
Do you notice any color change in distilled water? What property of water is revealed here?
Answer:
No’, water is neutral

Question 58.
What happens to the amount of H⁺ ions when a little acid is added to water?
Answer:
Increase

Question 59.
What happens if alkali is added?
Answer:
Amount OH^– increases

Question 60.
What is pH value?
Answer:
Determination of pH value is the scientific method for finding the acidic/alkaline nature of substances. The Danish scientist Sorensen devised the pH scale for this. The pH scale was devised based on the H⁺ ion concentration in the solution.

Question 61.
Observe the pH scale and answer the questions given below. What is the pH value of the neutral solution?

Answer:
7

Question 62.
What is the nature of the solution having pH value more than 7?
Answer:
Basic

Question 63.
What is the nature of the solution having pH value less than 7?
Answer:
Acidic

Question 64.
What is pH scale?
Answer:
The pH scale is the method used to express the acidic /basic nature of a substance based on the amount of H ions present in their aqueous solutions.
On the basis of the pH scale, the pH value of a neutral solution is 7. The pH value of acids is less than

Question 65.
How the pH value can be find out using pH solution?
Answer:
Add a drop of pH solution to the solution whose pH is to be determined or dip the pH paper into it. The pH value of the solution can be determined by comparing with the pH color chart.

Question 66.
Find the pH value of the following substances using the pH paper and complete the table given below.

Answer:

Question 67.
It is better to determine the pH of soil before farming? Why?
Answer:
The pH of soil is an important factor for crops. It is important to identify whether the soil of a region is suitable for a particular crop. Acidic soil is suitable for some crops while basic soil for a few others.

Question 68.
What are the products of the reaction between dilute hydrochloric acid and sodium hydroxide solution?
Answer:

Question 69.
Name the products formed when the common component of an acid and the common component of an alkali combine together.
Answer:
H₂O (water)

Question 70.
Which is the positive ion present in sodium hydroxide? Which is the negative ion present in hydrochloric acid?
Answer:
Na+ Cl^–

Question 71.
Write the chemical formula of the compound formed by the combination of these two ions. Identify this substance.
Answer:
Na+ + Cl → NaCI

Question 72.
What is naturalization?
Answer:
Neutralization is the process in which acid and alkali react with each other to form salt and water. Acid + Alkali → Salt + water

Question 73.
Complete the equation for the reaction between dilute sulphuric acid (H2S04) and magnesium hydrox¬ide Mg(OH)2.
Mg(OH)₂ + H₂SO₄ → + 2H₂O
Answer:
Mg(OH)₂ + H₂SO₄ MgSO₄ + 2H₂O

Question 74.
What are the products formed?
Answer:
Magnesium sulfate (MgSO₄) and water (H₂O)

Question 75.
Identify the salts given in the table and find out the acids and alkalies required for the formation of salt

Answer:

Question 76.
Write the name and symbol of some positive ions and negative ions.
Answer:

Question 77.
Write the name and symbol of some positive ions and negative ions.
Answer:
Formula — Name
KOH — Potassium hydroxide
K₂CO₃ — Potassium carbonate
KHCO₃ — Potassium bicarbonate
KNO₃ — Potassium nitrate
K₂SO₄ — Potassium sulphate
KHSO₄ — Potassium bisulphate
K₃PO₄ — Potassium phosphate
KH₂PO₄ — Potassium dihydrogen phosphate
Zn(OH)₂ — Zinc hydroxide
ZnCO₃ — Zinc carbonate
Zn(HCO₃)₂ — Zinc bicarbonate
Zn(NO3)2 — Zinc nitrate
ZnSO₄ — Zinc sulfate
Zn(HSO₄)₂ — Zinc bisulfate
Zn₃(PO₄)₂ — Zinc phosphate
Zn(H₂PO₄)₂ — Zincdihydrogen phosphate
Fe(OH)₂ — Ferrous hydroxide
FeCO₃ — Ferrous carbonate
Fe(HCO₃)₂ — Ferrous bicarbonate
Fe(NO₃)₂ — Ferrous nitrate
FeSO₄ — Ferrous sulfate
Fe(HSO₄)₃ — Ferrous bisulfate
Fe₃(PO₄)₂ — Ferrous phosphate
Fe(H₂PO₄)₂ — Ferrous dihydrogen phosphate
Fe(OH)₃ — Ferric hydroxide
Fe₂(CO₃)₃ — Ferric carbonate
Fe(HCO₃)₃ — Ferric bicarbonate
Fe(NO₃)₃ — Ferric nitrate
Fe₂(SO₄)₃ — Ferric sulphate
Fe(HSO₄)₃ — Ferric bisulphate
FePO₄ — Ferric phosphate
Fe(H₂PO₄)₃ — Ferric dihydrogen phosphate
CuOH — Cuprous hydroxide
Cu₂CO₃ — Cuprous carbonate
CuHCO₃ — Cuprous bicarbonate
CuNO₃ — Cuprous nitrate
Cu₂SO₄ — Cuprous sulphate
CuHSO₄ — Cuprous bisulphate
Cu₃PO₄ — Cuprous phosphate
CuH₂PO₄ — Cuprous dihydrogen phosphate
Cu(OH)₂ — Cupric hydroxide
CuCO₃ — Cupric carbonate
Cu(HCO₃)₂ — Cupric bicarbonate
Cu(NO₃)₂ — Cupric nitrate
CuSO₄ — Cupric sulphate
Cu(HSO₄)₂ — Cupric bisulphate
Cu₃(PO₄)₂ — Cupric phosphate
Cu(H₃PO₄)₂ — Cupric dihydrogen phosphate
NHOH — Ammonium hydroxide
(NH₄)₂CO₃ — Ammonium carbonate
NH₄HCO₃ — Ammonium bicarbonate
NH4NO3 — Ammonium nitrate
(NH₄)₂SO₄ — Ammonium sulphate
NH₄HSO₄ — Ammonium bisulfate
(NH₄)₃PO₄ — Ammonium phosphate
NH₄H₂PO₄ — Ammonium dihydrogen phosphate
Mn(OH)₂ — Manganous hydroxide
MnCO₃ — Manganous carbonate
Mn(HCO₃)₂ — Manganous bicarbonate
Mn(NO₃)₂ — Manganous nitrate
MnSO₄ — Manganous sulfate
Mn(HSO₄)₂ — Manganous bisulfate
Mn₃(PO₄)₂ — Manganous phosphate
Mn(H₂PO₃)₃ — Manganous dihydrogen phosphate

Question 78.
The name of few salts and their chemical formulae are given in the table. Complete the table adding names of more salts and write the positive ions and negative ions.

Answer:

Question 79.
What is the number of positive ions and negative ions in a ‘molecule’ of NaCI?
Anaswer:
Positive ions 1, Negative ions 1

Question 80.
What would be the sum of the charges of the posi¬tive ions and negative ions in a ‘molecule’ of NaCI?
Answer:
1⁺ + 1^– = 0 (zero)

Question 81.
Why slats are neutral in nature?
Answer:
Salts are electrically neutral. The sum of the charge of the positive ions and negative ions in a salt will be zero.

Question 82.
What are the method of writing chemical formulae of salts?
Answer:

• While writing the chemical formula, first write the symbol of the positive ion and then the symbol of the negative ion.
• Write the numbers indicating the charge of each ion as subscripts after interchanging them.
• Simplify the subscripts and write them in the smallest whole-number ratio.

Question 83.
Write the different stages in writing the chemical formulae of compounds formed by the combination of magnesium ion (Mg³⁺) with phosphate ion (PO₄³-) and carbonate ion (CO₃²-)
Answer:
Mg²⁺ PO₄³–
Mg²⁺CO₃²–
Mg₃ (PO₄)₂
Mg_2/2 (CO₃)_2/2
MgCO₃

Question 84.
Some positive ions and negative ions are given in the table. Write the name and chemical formulae of the maximum possible salts formed by them.
Positive ion — Negative ion
Ca²⁺ (calcium ion) — Cl^– (chloride ion)
NH₄⁺ (Ammonium ion) — SO₄²– (sulphate ion)
PO₄³– (Phosphate ion)
Answer:
1) Calcium chloride CaCl₂?
2) Calcium sulphate CaSO₄
3) Calcium phosphate Ca₃(PO₄)₂
4) Ammonium chloride NH₄Cl
5) Ammonium sulphate (NH₄)2SO₄
6) Ammonium phosphate (NH₄)3PO₄

Question 85.
Give example for some salts that are used as fertilizers.
Answer:

• Ammonium sulphate.(NH₄)₂SO₄
• Potassium chloride KCl
• Sodium nitrate NaNO₃

Question 86.
We use various salts in our daily life. A list of some of these salts and their chemical formulae are given in the table. Analyze the table and complete.

Answer:

Let Us Assess

Question 1.
Complete the chemical equations for the following ionization equation.

Answer:

Question 2.
Identify the symbol from the box and write against their names.
SO₃²– , NO₃^– , HCO₃^–, OH^–, CO₃²-, HSO₄^–
Carbonate —
Bisulphate —
Sulfite —
Nitrate —
Hydroxide —
Bicarbonate —
Answer:
Carbonate → CO₃²–
Bisulphate → HSO₃^–
Sulfite → SO₃²–
Nitrate → NO₃
Hydroxide → OH^–
Bicarbonate → HCO₃

Question 3.
a) Name the salt formed by the reaction between
magnesium hydroxide [Mg(OH)₂] and dil. hydrochloric acid (HCl).
b) Write the equation for the reaction
c) Which is the acid required for the preparation of magnesium sulfate?
Answer:
a) Magnesium Chloride
b) Mg(OH)₂ + 2HCl MgCl₂ + 2H₂O
c) H₂SO₄ (sulphuric acid)

Question 4.
List the cation and anions of the substance given in the table.

Answer:

Question 5.
A little distilled water is taken in a beaker.
A. What is the pH value of the distilled water?
B. What happens to the pH value when the following substances are added to the water? Justify your answer.
i) Caustic soda
ii) Vinegar
Answer:
A. Seven
B. i) pH value increases, solution becomes basic
ii) pH value decreases, solution becomes acidic

Question 6.
Match the column A, B, and C by identifying the correct chemical formulae and the use of the salts

Answer:

Question 7.
The pH values of some substances are given in the table. Analyze the table and answer the questions

a. Is blood acidic or basic in nature?
b. The pH value of pure milk is 6.4. Does the pH value increase or decrease when milk changes . to curd. Justify your answer
c. Among the substances given in the above table
(i) Which one is strongly basic?
(ii) Which one has weak acidic nature
Answer:
a) Basic
b) pH value decrease. Curd is lactic acid
c) i) Limewater
ii) Blood

Extended Activities

Question 1.
Organic acids are present in a number of substances we use in our daily life.
(eg. Tomato, orange, apple, grapes, curd, etc.) Identify the organic acids in each of them and tabulate.
Answer:
Tomato — oxalic acid
Orange — Citric acid
Apple — Malic acid
Grapes — Tartaric acid
Curd — Lactic acid, Butiric acid

Question 2.
Haven’t you conducted an activity to find the pH value of the soil related to different crops? Identify the pH values of soil samples collected from different places.
Prepare a list of the crops that are suitable for the soil of each area on the basis of its pH value
Answer:

Question 3.
a) Complete the equations of the ionization of phosphoric acid.
H₃PO₄ → H⁺ + H₂PO₄^– (Dihydrogenphosphate ion)
H₃PO₄^– → H+ + …………. (Hydrogenphosphate ion)
…….. → H⁺ + PO₄^3- (phosphate ion)
b) How many types of salts can be formed by phosphoric acid? Why?
c) Write the chemical name of the following salts.
Mg(H₂PO₄)₂
MgHPO₄
Mg₃(PO₄)₂
Answer:
a) H₂PO₄^– → H⁺ + HPO₄^2- (Hydrogenphosphate ion)
HPO₄^2- → H^– + PO₄^3- (phosphate ion)
b) It is tribasic
c) Magnessium dihydrogen phosphate Magnessium hydrogenphosphate Magnessium phosphate

Question 4.
Solution of sodium carbonate, potassium chloride, and ammonium sulfate are taken in separate beakers. Dip a litmus paper (red, blue) in each beaker.


Answer:

i) Observe the color change of litmus paper and tabulate.
ii) Name the acid and alkali that react to form each salt given above?
iii) Can you explain the color change of the litmus paper on the basis of the nature of the acid and alkali that react to form the salt?
(hint: Potassium chloride is a salt formed by the reaction between a strong acid and a strong alkali)

i) Salts formed by the reaction between a strong acid and a strong base will be neutral in nature, eg: KCI
ii) Salts formed by the reaction between a strong base and weak acid will be slightly basic eg: Na2CO3
iii) Salts formed by the reaction between a weak base and strong acid will be slightly acidic eg:(NH4)2SO4

Acids, Bases, Salts More Questions and Answers

Question 1.
Non-metalic oxides like CO₂, SO₂, and NO₂ shows acidic nature, justify it.
Answer:
Compounds formed by the reaction of the above nonmetal oxide dissolves in water shows acidic character.

Question 2.
Take quick lime (Calcium oxide) in a beaker containing water. Take a little of this in a test tube and show a red litmus paper.
Answer:
Red litmus paper turns to blue because calcium oxide dissolves in water to form calcium hydroxide. It is basic in nature.

Question 3.
Complete the equation of the reaction between calcium oxide and water.
Answer:
CaO + H₂O → Ca(OH)₂

Question 4.
What can be inferred about the nature of this substance from the litmus test?
Answer:
Alkaline nature

Question 5.
Classify the following oxides into acidic oxide and basic oxide
SO₃, NO₂, CaO, K₂O P₂O₅, Na₂O, CO₂, MgO
Answer:

Question 6.
Try to write the chemical equation for the reaction of Fe with hydrochloric acid.
Answer:
Fe + 2 HCI → FeCl₂ + H₂

Question 7.
Analyze the chemical equation for the reactions taking place when hydrochloric acid dissolves in water.
Answer:
HCl → H⁺ + Cl^–
H⁺ + H₂O → H₃O⁺ (Hydronium ion)

Question 8.
Explain the basis of classification of acid into monobasic, Dibasic and tribasic acids.
Answer:
An acid molecule dissolves in water to liberate H⁺ ions. Based on this acids are classified into monobasic, Dibasic and tribasic acids. HCl is a monobasic acid.

Question 9.
Explain the dissociation of H2SO4
Answer:
H₂SO₄ → H⁺ + HSO₄⁺ (Bisulphate ion)
HSO₄– → H⁺ + SO₄²⁺ (Sulphate ion)

Question 10.
Classify the following acids into monobasic, dibasic and tribasic acids,
H₂CO₃, HNO₃, H₃PO₄, H₂SO₄, HCl, H₂S₄
Answer:

Question 11.
During the rainy season, the farmers are using slaked lime in agricultural fields, give reason.
Answer:
To reduce the acidity of the soil.

Question 12.
Write the chemical formula of slaked lime.
Answer:
Calcium hydroxide – Ca(OH)₄

Question 13.
Most of the alkalies are also known by the common names in addition to their chemical names. Caustic soda, milk of lime, milk of magnesia and caustic potash are the common names of some alkalies. Identify the chemical formula with the help of the given table.
Answer:

Question 14.
Observe the chemical equation of the dissolution of Sodium hydroxide in water.
NaOH → Na⁺ + OH^– (Hydroxide ion)
Now complete the given chemical equation for the ionization of Calcium hydroxide.
Ca(OH)2 → + ………. + …………..
Answer:
Ca(OH)₂ → Ca⁺ + 2OH^–

Question 15.
Which is the common ion released when alkalies dissolved in water?
Answer:
OH^–

Question 16.
Difference between bases and alkalies?
Answer:
Bases are compounds that are opposite in acids in their characteristics.
Bases dissolving in water are alkalies. The metal hydroxide which dissolves in water functioning as strong alkalies.
Sodium hydroxide, Potassium hydroxide are alkalies, but Al(OH)₃, Ca(OH)₂ are bases.

Question 17.
What is meant by a neutralization reaction?
Answer:
An acid combines with alkali to nullify their individual properties. Such reactions are called neutralization reaction.

Question 18.
Give equation for the neutralization reaction of Sodium hydroxide with Hydrochloric acid.
Answer:
NaOH + HCl → NaCl + H₂O

Question 19.
If we add small quantity of acid to water, what happens to the quantity of H⁺ ion?
Answer:
Quantity of H⁺ ion increases.

Question 20.
What change occurs when alkali is added?
Answer:
Quantity of OH⁺ ion increases.

Question 21.
Complete the table and find the pH value by using pH paper of the following substances.
Answer:

Question 22.
If the pH value increases whether acid or alkali character increases?
Answer:
Alkali character increases

Question 23.
If the pH value increases whether the H⁺ ion concentration decreases or increases?
Answer:
Decreases

Question 24.
The names of a few salts and their chemical formulas are given below. Find the cations & anions and complete the table.
Answer:

Question 25.
Can you find out the acid and alkali responsible for the formation of the salts given in the table from their chemical formula
Answer:

Question 26.
Prepare a table by writing the chemical formula of more salts that you are familiar with and also the names of the acid and alkalies from which they are formed.
Answer:

Question 27.
Find out how the chemical formula of the salts are written analyzing the table.
Answer:

Question 28.
Give the salts used as chemical fertilizers?
Answer;
Ammonium Sulphate – (NH₄)₂SO₄
Potassium Chloride – KCl
Sodium Nitrate – NaNO₃

Question 29.
a) Complete the chemical equation for the ionization of Phosphoric acid.
H₃PO₄ → H⁺ + H₂PO₄⁺
H₃PO₄⁺ → H+ + ……….
………. → H⁺ + PO₄^3-
b) Based on the ionization equation given above Phosphoric acid is a tribasic acid? Justify it.
Answer:
a) H₃PO₄ → H⁺ + H₂PO₄^2-(Dihydrogen Phosphate ion)
H₂PO₄^– → H⁺ + HPO₄^2- (Hydrogen Phosphate ion)
HPO₄^2- → H⁺ + PO₄^3- (Phosphate ion)
b) In Phosphoric acid in aqueous solution number of H⁺ ion release is 3. Hence it is a tribasic acid.

Question 30.
Two solutions A and B having pH value 5 and 9, respectively. Which one shows acidic character and which one shows alkaline character. Why?
Answer:
A shows acidic character because the pH value is below 7, B shows alkaline character because the pH value is above 7.

Question 31.
List the cations and anions of the substances given in the table.

Answer:

Question 32.
Some cations and anions are given. Write the chemical formula of all the salts possible by combining them.

Answer:

Question 33.
Name the salt formed by the reaction between Potassium hydroxide (KOH) and Nitric acid (HNO₃).
Answer:
a) Potassium Nitrate
b) KOH + HNO₃ → KNO₃ + H₂O

You can Download Non-Metals Questions and Answers, Summary, Activity, Notes, Kerala Syllabus 9th Standard Chemistry Solutions Part 2 Chapter 6 help you to revise complete Syllabus and score more marks in your examinations.

Kerala State Syllabus 9th Standard Chemistry Solutions Chapter 6 Non-Metals

Non-Metals Textual Questions and Answers

Activities In The Text

9th Class Chemistry Chapter 6 Solutions Kerala Syllabus Question 1.
Which are the non-metals familiar to you?
Answer:
Nitrogen, Oxygen, Chlorine, Argon

Class 9 Chemistry Chapter 6 Notes Kerala Syllabus Question 2.
Is it interesting to see the balloons flying up in the air? Which is the gas-filled in these balloons?
Answer:
Hydrogen.

Kerala Syllabus 9th Standard Chemistry Chapter 6  Question 3.
Which gas is mainly filled in cylinders used in hospitals for artificial respiration?
Answer:
Oxygen

Kerala Syllabus 9th Standard Chemistry Notes Question 4.
Which is the gas-filled in tires to increase their efficiency?
Answer:
Nitrogen

Hsslive Guru 9th Chemistry Kerala Syllabus Question 5.
Which are the gases present in air

Which is the most abundant gas in air?
Answer:
Nitrogen

Chemistry 9th Class Notes Kerala Syllabus Question 6.
Write the constituent elements of food materials?
Answer:
Carbohydrates: carbon, hydrogen, oxygen
Protein: carbon, hydrogen, oxygen, nitrogen
Fat: carbon, hydrogen, oxygen

9th Chemistry Notes Kerala Syllabus Question 7.
List the constituent elements of some plastics?
Answer:
PVC: Carbon, hydrogen, chlorine Polythene: Carbon, hydrogen Carbon, hydrogen, oxygen, nitrogen, chlorine are nonmetals

Chemistry Class 9 Chapter 6 Kerala Syllabus Question 8.
What do you know about hydrogen gas?
Answer:
Hydrogen is the major component in the sun and stars. A very small quantity of hydrogen is seen in the atmosphere in free state. Water is a major com¬pound of hydrogen. Hydrogen is present in large amounts in bio substances.

Hss Live Guru 9 Chemistry Kerala Syllabus Question 9.
List out the hydrogen compounds known to you
Answer:
1. H₂SO₄ HCI HNO₃ H₂CO₃
2. H₂O H₂O₂ NaOH H₂PO₄

Hsslive Guru 9 Chemistry Kerala Syllabus Question 10.
Explain the preparation of hydrogen in the laboratory?
Materials required: Test tube, zinc granule, dilute hydrochloric acid, lighted match stick.

Procedure: Take 5 ml. dilute hydrochloric acid in a test tube and add some zinc granule to it. Bring a burning match stick at the mouth of the test tube. What do you observe?
Answer:
The gas burns with a pop sound

Class 9 Chemistry Notes Kerala Syllabus Question 11.
Which gas is produced?
Answer:
Hydrogen.

Chemistry Notes Class 9 Kerala Syllabus Question 12.
Write the balanced equation of this chemical reaction.
Answer:
Zn + 2HCl → ZnCl₂ + H₂

Hss Live Guru Chemistry 9th Kerala Syllabus Question 13.
What are the reactants and products in this reaction?
Answer:
Zn, HCl – Reactants ZnCl₂ + H₂ – Products

Kerala Syllabus 9th Standard Chemistry Solutions Question 14.
How is zinc chloride formed along with hydrogen gas in this chemical reaction?
Answer:
During this chemical reaction, Zn atom replaces hydrogen in hydrochloric acid.

Chemistry Class 9 Notes Kerala Syllabus Question 15.
What are displacement reactions?
Answer:
Reactions, where an element in a compound is displaced by another element, is called displacement reactions/ Substitution reactions.

9 Standard Chemistry Kerala Syllabus Question 16.
Give examples for displacement reactions.
Answer:
1) Mg + 2HCl → MgCl₂ + H₂
2) Zn + H₂SO₄ → ZnSO₄ + H₂
3) Mg + 2HNO₃ → Mg(NO₃ )₃ + H₂
4) Zn + CuSO₄ → ZnSO₄ + Cu
5) 2NaBr + Cl₂ → 2NaCl + Br₂
6) CH₄ + Cl₂ → CH₃Cl + HCl

Question 17.
You have seen hydrogen balloons fly up in the air. What can you infer about the density of hydrogen from this?
Answer:
The density of hydrogen is less than that of air.

Question 18.
What is the reaction between hydrogen and oxygen?
Answer:
Hydrogen burns in oxygen to form water. This is an exothermic reaction. (Water is also formed when electric sparks are passed through a mixture of hydrogen and oxygen)
2H₂ + O₂ → 2H₂O + heat

Question 19.
What is a combination reaction?
Answer:
The reaction in which two or more simple substances (elements/compounds) combine to form a compound is called combination reaction.
eg: 2H₂ + O₂ → 2H₂O

Question 20.
What is the reaction between hydrogen and chlorine?
Answer:
Hydrogen combines with chlorine in the presence of sunlight to form hydrogen chloride

Question 21.
Give examples for combination reactions.
1) N₂ +3H₂ → 2NH₃
2) 2Mg + O₂ → 2MgO
3) H₂ + S → H₂S
4) 2Na + H₂ → 2NaH
5) CaO + H₂O→ Ca(OH)₂

Qn. 22
List the uses of hydrogen
Answer:

• For the industrial production of ammonia and methanol
• To saturate unsaturated oils
• As a fuel

Question 23.
Observe and analyse the graph showing the heat energy released during the combustion of various fuels.

Which among the fuels given has the highest calorific value?
Answer:
Hydrogen

Question 24.
What is calorific value?
Answer:
The calorific value of a fuel is the heat energy released from one unit mass of that fuel on complete combustion.

Question 25.
Which fuel has the highest calorific value?
Answer:
Hydrogen

Question 26.
What will be the product formed when hydrogen burns in air?
Answer:
Water(H20)

Question 27.
What are the advantages of using hydrogen as a fuel?
Answer:

• High calorific value
• No environmental pollution
• Availability is very high

Question 28.
What are the limitations of using hydrogen as a fuel?
Answer:

1. Hydrogen is a gas that burns explosively in air
2. Distribution and storing the gas is not easy.

Question 29.
List out some compounds containing oxygen.
Answer:

• C₆H₁₂O₆
• CuO
• CaCO₃
• H₂SO₄

Question 30.
Prepare and present a short note on the role of plants in maintaining the oxygen level.
Answer:
In the presence of sunlight, the chlorophyll present in plants forms glucose by combining CO₂ and water. As a result of this reaction (photosynthesis), oxygen is liberated. This helps to maintain the oxygen level in the atmosphere.
6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂

Question 31.
What do know about the presence of oxygen on earth
Answer:

From the table you might have understood that the level of oxygen is very high in nature

Question 32.
Explain the preparation of oxygen in the laboratory with a figure?

Question 33.
Write the apparatus materials used for the preparation of oxygen?
Answer:

• Dry boiling tube
• Crystal of potassium permanganate
• Spirit lamp
• Glowing splinter

Question 34.
Introduce a glowing matchstick into the boiling tube. What do you observe?
Answer:
The glowing matchstick flares up.

Question 35.
Presence of which gas is indicated by the flaring up of the glowing matchstick?
Answer:
oxygen

Question 36.
Complete the equation of this chemical reaction.

Answer:

Question 37.
What is decomposition?
Answer:
Decomposition is the process of forming two or more products due to the decomposition of a compound.

Question 38.
What happens during the electrolysis of water? Com¬plete its chemical equation given below

Answer:

Question 39.
Put a (✓) mark against the correct option related to oxygen from those given below.

Answer:
Colour — Yes/ No ✓
Odour — Yes/ No ✓
Solubility in Water — Soluble✓/insoluble
Density — More than air ✓/less than air
Flammability — supports combustion✓

Question 40.
What is combustion?
Answer:
The burning of a substance in oxygen is called combustion.

Question 41.
Take some sulphur in a spatula and burn it. What do you observe?
Answer:
Sulphur burns. The smell of gun powder.

Question 42.
How does oxygen react with non-metals?

Answer:
Oxygen reacts with the non-metals such as carbon and hydrogen to produce carbon dioxide and water respectively,
e.g: C + O₂ → CO₂.
2H₂ + O₂ → 2H₂O

Question 43.
Have you notice that the lustre of metals like aluminium and ion fades gradually. Give reason?
Answer:
The reason for this is the formation of oxide of these metals when they combine with oxygen

Question 44.
Explain the uses of oxygen
Answer:

• For combustion
• As an oxidant in rocket fuels
• For artificial respiration

Question 45.
What is ozone?
Answer:
Oxygen is seen as diatomic molecule that is formed by combining two oxygen atoms.
But ozone is a triatomic molecule containing three oxygen atoms. (03)
Ozone is found in the stratosphere, a layer of atmosphere.

Question 46.
How ozone is formed in the atmosphere?
Ozone is present mostly in the stratosphere of the atmosphere. Atmosphere oxygen dissociates on absorption of high energy ultraviolet radiation. The oxygen atoms thus formed combine together to form 03 molecule.

Question 47.
Depletion of ozone in the atmosphere reduces the absorption of ultraviolet rays. Justify the statements.
Answer:
Chloroflouro carbons are responsible for the depletion of the ozone layer. Chlorofluorocarbon released into the atmosphere reach the stratosphere and breakdown by the action of ultraviolet radiation releasing chlorine the chlorine decomposes ozone molecules into oxygen. This disturbs the equilibrium in the ozone – oxygen cyclic process. Hence the depletion of ozone in the atmosphere reduces the absorption of ultraviolet rays.

Question 48.
Howto reducing the rate of depletion of ozone layer?
Answer:
Today the use of CFC is being controlled in most of the countries. Harmful CFC are replaced nowadays with safer substances this has helped in reducing the rate of depletion of ozone layer.

Question 49.
Nitrogen is the chief constituent of atmospheric air have you ever thought of the advantage of having a greater quantity of nitrogen in the atmosphere?
Answer:
Nitrogen molecule has a triple bond (N = N). Because of this strong bond, nitrogen is most inert oxygen helps in combustion while nitrogen plays on important role in regulating the rate of combustion of oxygen.

Question 50.
What are the different ways in which nitrogen is obtained by plants?
Answer:

• By bio decomposition
• Through fertilizers
• By nitrogen-fixing by bacteria

Question 51.
“It is said that lightning is a boom to plants”. Justify the statement?
Answer:
During lightening the triple bond in nitrogen breaks and combine with the atmospheric oxygen to form nitric oxide (NO)
N₂+O₂ → 2NO
Nitric oxide thus formed further combines with more amount of oxygen to form nitrogen dioxide (NO₂)
2NO + O₂ → 2NO₂
Nitrogen dioxide dissolves in rainwater in the presence of oxygen and reaches the soil as nitric acid (HNO₃)
4NO₂ + 2H₂O + O₂ → 4HNO₃
Nitric acid reacts with the minerals in the soil to form nitrate salts which is absorbed by the plants. So it is said that lightning is a boom to plants.

Question 52.
Can you list out which other means are there for getting greater amount of elements for plants?
Answer:

• Use of organic fertilizers
• Use chemical fertilizers
• Bio decomposition
• Through nitrogen fixation

Question 53.
List the merits and limitations of the application of organic fertilizers?
Answer:
Merits:

• Eco-friendly
• Preserve the inmate nature of the soil

Limitation:

• Biodegradation needs time so it cannot easy to absorbed by plants in time.
• Presence of microorganism is necessary.
• Storage and transportation not easy.

Question 54.
What are the other uses of nitrogen?
Answer:

• In production of nitrogenous fertilizers
• To fill in the tyres of vehicles
• Liquified nitrogen as a refrigerant
• Tc avoid the presence of oxygen in packed foods
• In the manufacture of ammonia

Question 55.
List out the chlorine compounds you are familiar with.
Answer:

• Hydrogen chloride (HCl)
• Sodium chloride (NaCl)
• Potassium chloride (KCl)

Question 56.
Draw the arrangement for the preparation of chlorine in the laboratory.
Answer:

Question 57.
Write the balanced chemical equation?
Answer:
2KMnO₄ +16HCl → 2KCl + 2MnCl₂ + 8H₂O + 5Cl₂

Question 58.
What are the reactants required for the preparation of chlorine?
Answer:
Potassium permanganate, Con. HCI

Question 59.
What are the products obtained?
Answer:
Potassium chloride (KCl)
Manganous chloride (MnCl₂)
Water (H₂O)
Chlorine (Cl₂)

Question 60.
In laboratory preparation of chlorine why chlorine gas is passed through water?
Answer:
Hydrogen chloride vapours conning along with chlorine is removed by passing it through water.

Question 61.
Which method is used to remove the water vapour formed along with chlorine?
Answer:
The chlorine gas formed can be passed through con. H₂SO₄ because it can absorb the water vapour formed along with chlorine.

Question 62.
Observe the figure and see the way in which chlorine is being collected in a gas jar? Why this method is used?
Answer:
The density of Cl₂ is greater than that of air hence it can be collected by the upward displacement of air.

Question 63.
Explain the physical properties of chlorine?
Colour – colourless
Odour – pungent smell
Density -greater than that of air

Question 64.
Describe an experiment to show the bleaching action of chlorine?
Answer:
Prepare and store dry chlorine in a gas jar. Put some moist petals of colour flowers and pieces of coloured paper in the jar. The observation is chlorine gas can decolourise coloured substances by bleaching.

Question 65.
Write the chemistry behind the bleaching action of chlorine?
Answer:
Chlorine gas reacts with the water to give hydrochloric acid hypochlorous acid (HClO)
Cl₂ + H₂O → HCl + HOCl
Hypochlorous acid decomposes and liberate atomic oxygen.
HClO → HCl + [O]
This atomic oxygen oxidises coloured substances.

Question 66.
Write the uses of chlorine?
Answer:

• For bleaching
• For the preparation of insecticides
• For removing stains in the fabric
• For purification of water
• For the preparation of bleaching powder

Question 67.
How bleaching powder is prepared?
Answer:
Bleaching powder is prepared by passing dry chlorine gas over dry slaked lime.

Question 68.
How bleaching powder act as a disinfectant?
Answer:
Chlorine, liberated when bleaching powder reacts with water, helps disinfection. Bleaching powder is a good source of chlorine.

Question 69.
How the presence of a chloride salt can be confirmed?
Answer:
When silver nitrate solution is added to the given salt solution, if a white curdy precipitate soluble in ammonium hydroxide solution, is formed the pres¬ence of a chloride salt can be confirmed.
NaCl + AgNO₃ → AgCl + NaNO₃

Question 70.
Analyse the chemical equation given below.
NaCl + AgNO₃ → AgCl + NaNO₃
Which is the ion combined with sodium ion in the
first reactant NaCl?
Answer:
Cl^–

Question 71.
To which metal ion, is this ion combined in the product?
Answer:
Ag+

Question 72.
To which metal ion is this nitrate ion combined now in the product.
Answer:
Na⁺

Question 73.
Are the ions interchanged here?
Answer:
Yes

Question 74.
What is double decomposition reaction?
Answer:
Double decomposition is a reaction in which two compounds when react with each other, interchange their ions to form two new compounds.
eg: 1) NaCl + AgNO₃ → AgCl + NaNO₃
2) H₂SO₄+BaCl₂ → 2HCl + BaSO₄

Question 75.
Arrange the chemical reactions given below in the table under the heads combination reaction, decom¬position, displacement reactions and double decomposition.
a) 2KCl → 2K + Cl₂
b) CaCO₃ → CaO + CO₂
c) 2Hl → H₂+l₂
d) KCl + AgNO₃ → AgCl + KNO₃
e) Mg + 2HCl → MgCl₂ + H₂
f) 2H₂ + O₂ → 2H₂O
g) Mg + H₂SO₄ → MgSO₄ + H₂
h) Na₂SO₄ + BaCl₂ → BaSO₄ + 2NaCl
Answer:
a) Decomposition
b) Decomposition
c) Combination
d) Double decomposition
e) Displacement
f) Combination
g) Displacement
h) Double decomposition

Let’S Assess

Question 1.
Some chemicals are given in the box. Find out and write down the chemicals needed to prepare oxygen and hydrogen in laboratory.
Sulphuric acid, hydrochloric acid, sodium nitrate, zinc, potassium permanganate, ammonium chloride, water.
Answer:
Oxygen — Potassium permanganate
Hydrogen — Zinc, Hydrochloric acid

Question 2.
Find out to which gases are the following statements related?
a) The gas which is combustible and is formed through the electrolysis of water
b) The gas that is used for water purification.
c) The element inevitable for the growth of plants.
d) The gas formed by the thermal decomposition of KMnO.
Answer:
a) Hydrogen
b) Chlorine
c) Nitrogen
d) Oxygen

Question 3.
Certain nonmetals and their uses are given in the wrong order in the table below. Match them correctly.
Element — Uses
Hydrogen — Disinfectant
Oxygen — Refrigerant
Chlorine — Fuel
Nitrogen — Biodegradati
Answer:
Element — Uses
Hydrogen — Fuel
Oxygen — Biodegradati
Chlorine — Disinfectant
Nitrogen — Refrigerant

Question 4.
a) What are the chemicals used for the preparation of chlorine in the laboratory?
b) why is chlorine passed through sulphuric acid during its preparation?
c) how will you prepare bleaching powder?
d) Name the gas that comes out of bleaching powder in the presence of water?
Answer:
a) Potassium permanganate concentrated HCl
b) It can absorb water vapour in the chlorine gas obtained
c) Bleaching p[owder is prepared by passing dry chlorine over dry slaked lime.

Question 5.
“We should give up chemical fertilizers completely and promote the use of organic fertilizers”. Do you agree with this statement? Substantiate your answer.
Answer:
Yes

1. Organic fertilizers are echofriendly.
2. Preserve the inmate nature of the soil.
3. Does not create any health problem.

Question 6.
Classify the given chemical reactions in the table below.
a) Mg + O₂ → 2MgO
b) H₂ + l₂ → 2HI
c) 2H₂O → 2H₂ + O₂
d) NaCl + AgNO₃ → AgCl + NaNO₃
e) ZnSO₄ + BaCl₂ → BaSO₄ + ZnCl₂
f) Zn + H₂SO₄ → ZnSO₄ + H₂
g) FeSO₄ + Zn → ZnSO₄ + Fe
h) CaCO₃ → CaO + CO₂
Answer:
a) Combination
b) Combination
c) Decomposition
d) Double decomposition
e) Double decomposition
f) Displacement
g) Displacement

Extended Activities

Question 1.
Conduct a discussion on how nitrogen cycle benefits plants and animals.
Answer:
Nitrogen cycle helps to maintain the level of nitrogen in the atmosphere stable. During lightning nitro¬gen in the atmosphere combines with oxygen and forms nitric oxide. This nitric oxide combines with oxygen again to form nitrogen dioxide Nitrogen dioxide in the presence of oxygen dissolves in rainwater and reaches earth as nitric acid. This nitric acid combines with compounds present in earth and changes them to nitrates. Plants absorb this nitrates easily. Through plant products, nitrogen reacts animals also When plants and animals decay nitrogen again reaches the atmosphere this process goes on continuously. So the amount of nitrogen is kept constant.

Question 2.
Conduct a seminar on ‘Ozone Depletion and its Solutions’
Answer;
Ozone is present mostly in the stratosphere of the atmosphere. Atmosphere oxygen dissociates on absorption of high energy ultraviolet radiation. The oxy¬gen atoms thus formed combine together to form 03 molecule.

Ozone absorbs low energy ultraviolet radiations and decomposes back to oxygen as a result of this cyclic process the level of ozone remains constant. In the atmosphere.
The energy required for this process is obtained from the ultraviolet process is obtained form the ultraviolet radiations emitted by the sun. Due to this such harmful radiations doe not reach the earth excessively.

Chloroflouro carbons are responsible for the depletion of the ozone layer. Chlorofluorocarbon released into the atmosphere reach the stratosphere and breakdown by the action of ultraviolet radiation releasing chlorine the chlorine decomposes ozone molecules into oxygen. This disturbs the equilibrium in the ozone – oxygen cyclic process. Hence the depletion of ozone in the atmosphere reduces the absorption of ultraviolet rays.

Today the use of CFC is being controlled in most of the countries. Harmful CFC are replaced nowadays with safer substances this has helped in reducing the rate of depiction of ozone layer.

Question 3.
Take 5 ml hydrogen peroxide (H202) solution in a test tube. Add a little manganese dioxide to it. Bring a burning matchstick into the test tube. What do you observe? Find reason for your observation?
Answer:
Observation: The burning matchstick flares up. Reason: In the presence of manganese dioxide, hydrogen peroxide decomposes quickly and liberates oxygen gas. The presence of oxygen flaring up of the match stick.
2H₂O₂ → 2H₂O + O₂

Non-Metals More Questions and Answers

Question 1.
Certain gases are given below Hydrogen oxygen-nitrogen chlorine, carbon dioxide
a) Which is a combustible gas?
b) Which gas support combustion?
c) Which gas has the tendency to limit combustion?
d) Which gas resist combustion?
Answer:
a) Hydrogen
b) Oxygen
c) Nitrogen
d) Carbondioxide

Question 2.
Classify the following gases into molecules having single bond, double bond and triple bond
a) Nitrogen
b) Chlorine
c) oxygen
Answer:
Single bond – Chlorine
double bond – Oxygen
Triple Bond-Nitrogen

Question 3.
Which one of the following doesn’t belong to the group?
Carbohydrates, protein, polythene, Fats
Answer;
Polythene

Question 4.
The components in food materials are given below. Filling the missing ones
a) Carbohydrate – Carbon, Hydrogen, …………
b) Protein – Carbon, Hydrogen, Oxygen,
c) Fats – Carbon, Hydrogen,
Answer:
a) Oxygen
b) Nitrogen
c) Nitrogen

Question 5.
Identify the relation in the first pair and fill up the missing ones in the second pair
a) PVC: Carbon, Hydrogen, Chlorine
…………..: Carbon, Hydrogen
b) Aqueous solution of CO2: H2CO3
Aqueous solution of SO2:
c) Na₂CO₃.10.H₂O : Washing soda
NaHCO₃ :…….
Answer;
a) Polythene
b) H2SO3
c) Baking soda

Question 6.
Certain gases are given in column A. Chemicals required to produce the gases are given in column B. Match them suitably.

Answer:

You can Download Breathing for Energy Questions and Answers, Summary, Activity, Notes, Kerala Syllabus 9th Standard Biology Solutions Part 1 Chapter 4 help you to revise complete Syllabus and score more marks in your examinations.

Kerala State Syllabus 9th Standard Biology Solutions Chapter 4 Breathing for Energy

Breathing for Energy Textual Questions and Answers

……… is essential for releasing energy from nutrients.
Answer:
Oxygen

Kerala Syllabus 9th Standard Biology Notes Chapter 4 Question 2.
Oxygen from the atmospheric air is taken into the body through the ………. system.
Answer:
Respiratory

Breathing For Energy Class 9 Kerala Syllabus Question 3.
List of important parts of the respiratory system in humans?
Answer:
Nostril, Nasal Cavity, Trachea, Bronchus, Bronchiole, Alveolus, Pleura, and Diaphragm

Breathing For Energy Class 9 Notes Kerala Syllabus Question 4.
……….. is the pathway which extends from the external nostrils to the internal alveoli.
Answer:
The respiratory tract

Kerala Syllabus 9th Standard Biology Notes Chapter 4 English Medium Question 5.
An opening through which air passes in and out of the body is called
Answer:
Nostril

Class 9 Biology Chapter 4 Notes Kerala Syllabus Question 6.
……….. connects nostrils with the pharynx
Answer:
Nasal cavity

Class 9 Biology Chapter 4 Kerala Syllabus Question 7.
State whether true or false
There are no cartilaginous rings in the bronchioles
Answer:
True

Biology 9th Class Chapter 4 Notes Kerala Syllabus Question 8.
Which part of respiratory system takes place in the exchange of gases?
Answer:
Alveoli

9th Class Biology Notes Chapter 4 Kerala Syllabus Question 9.
……… is the double-layered protective membrane of the lungs.
Answer:
Pleura

9th Class Biology Chapter 4 Kerala Syllabus Question 10.
What is the function of pleura?
Answer:
Pleural fluid seen in between the membraneous layers prevents friction between lungs and walls of the thoracic cavity. ‘

Kerala Syllabus 9th Standard Biology Notes Question 11.
Complete the word relation
Bronchus: cartilaginous rings
………..: no cartilaginous rings
Answer:
Bronchiole

Class 9 Biology Chapter 4 Kerala Syllabus Question 12.
……… is a long tube strengthened by ‘C’ shaped cartilaginous rings
Answer:
Trachea

Biology Class 9 Chapter 4 Notes Kerala Syllabus Question 13.
Which is the muscular wall that separates thoracic and abdominal cavities?
Answer:
Diaphragm

Class 9 Biology Notes Chapter 4 Kerala Syllabus Question 14.
Prepare a table of parts and functions of the respiratory system.
Answer:

9th Biology Chapter 4 Kerala Syllabus Question 15.
Complete the flow chart of the pathway of atmospheric air from the nostrils to the alveoli
Answer:
Nostrils → Nasal cavity → Trachea → Bronchus Bronchiole → Alveoli

Atmospheric Air In To Lungs

9th Class Biology Chapter 4 Notes Kerala Syllabus Question 16.
What helps in variation in volume of the thoracic cavity?
Answer:
The combined working of intercostal muscles and the diaphragm help in increasing and decreasing the volume of the thoracic cavity.

9 Class Biology Chapter 4 Kerala Syllabus Question 17.
In humans, tidal volume is about …….. ml
Answer:
500ml

Biology Class 9 Chapter 4 Kerala Syllabus Question 18.
Complete the table given below

Answer:

Biology Chapter 4 Class 9 Kerala Syllabus Question 19.
What is the surface area of the skin that covers the entire body?
Answer:
2 sq. mtrs

Kerala Syllabus 9th Standard Biology Notes Malayalam Medium Chapter 4 Question 20.
Surface area of both the lungs together turn up to be at least…. sq. mtrs.
Answer:
70

Exchange Of Gases In The Alveoli

Biology Chapter 4 Class 9 Notes Kerala Syllabus Question 21.
How far is the structure of alveoli suitable for the exchange of respiratory gases like oxygen and carbon dioxide?
Answer:
Alveoli increase the respiratory surface area in lungs. The large surface area help in the easy exchange of respiratory gases.

Class 9 Chapter 4 Biology Notes Kerala Syllabus Question 22.
Explain the exchange of gases in alveoli?
Answer:
Alveoli increase the respiratory surface area in lungs. This large surface area help in the easy exchange of respiratory gases. Alveoli are surrounded by numerous capillaries. The inner wall of the alveoli is always kept moist. During inspiration, the concentration of oxygen inside the alveoli is higher than that of blood capillaries whereas the concentration of carbon dioxide in blood capillaries is higher than that of alveoli. As a result oxygen from the alveoli diffuses to the capillaries and carbon dioxide from capillaries diffuses to the alveoli

Biology Class 9 Chapter 4 Question Answers Kerala Syllabus Question 23.
The average amount of hemoglobin in a healthy man is
Answer:
15gm/100 ml blood

Chapter 4 Biology Class 9 Notes Kerala Syllabus Question 24.
15gm/100 ml blood : Haemoglobin: man
……… : Haemoglobin: Woman
Answer:
13 gm/100ml blood

Chapter 4 Biology Class 9 Kerala Syllabus Question 25.
Complete the flow chart given below

Answer:

Question 26.
What is the compound formed by the combination of oxygen and hemoglobin?
Answer:
Oxyhaemoglobin

Question 27.
……….. is caused when the amount of hemoglobin in the blood decreases.
Answer:
Anemia

To Release Energy

Question 28.
What do you mean by cellular respiration?
Answer:
The process by which energy is released from glucose in cells is called cellular respiration.

Question 29.
Energy is released mainly from
Answer:
Glucose

Question 30.
Name the first phase in cellular respiration
Answer:
Glycolysis

Question 31.
Glycolysis: Cytoplasm
………: Mitochondria
Answer:
Krebs’’ cycle

Question 32.
Complete the table

Answer:

Question 33.
“Food containing iron should be taken included in diet,” said Sabari. Do you agree with this opinion? Why?
Answer:
Yes. I agree with this opinion because iron molecules
are essential for the synthesis of hemoglobin

Question 34.
Complete the worksheet of cellular respiration?

Answer:

Question 35.
Find the relation between respiration and photosynthesis and complete the table.

Answer:

1. Food production, energy released from glucose
2. Dark reaction and light reaction, Glycolysis and Krebs’ cycle
3. CO2 + water, Glucose + Oxygen
4. Glucose + Oxygen, CO2 + water + 30 ATP

Expulsion Of Carbon Dioxide

Question 36.
Water is eliminated from the body in the form of…. & …..
Answer:
Sweat and urine

Question 37.
What are the major byproducts of respiration?
Answer:
Carbon dioxide and water

Question 38.
The …… & ………. changes back to carbon dioxide in the lungs.
Answer:
Carbamino hemoglobin and bicarbonate.

When Carbon Dioxide Becomes Excessive

Question 39.
What is Homeostasis?
Answer:
Maintenance of internal equilibrium by removal of harmful materials is called homeostasis.

Question 40.
How does increased amount of carbon dioxide affect the internal environment of our body?
Answer:
Carbon dioxide formed by the cellular respiration combines with water present in and out of the cell to form carbonic acid and this increases the activity in the body, which in turn changes the internal environment.

Question 41.
What is the role of the respiratory system in maintaining homeostasis?
Answer:
The respiratory system helps in the maintenance of homeostasis by eliminating carbon dioxide.

Respiration Without Oxygen

Question 42.
Prepare a flow chart relating to Anaerobic respiration
Answer:

Question 43.
Name some microorganisms live without oxygen?
Answer:
Bacteria, yeast, etc.

Question 44.
What is fermentation?
Answer:
Fermentation is the process of the production of lactic acid or alcohol from glucose by anaerobic respiration.

Question 45.
Merits of Anaerobic respiration – prepare a flow chart
Yeast  Fermenting batter to soften it
↑
Anaerobic
respiration
↓
Lactobacillus bacteria  Curding milk

Question 46.
Describe a circumstance anaerobic respiration takes place in human beings
Answer:
During straneow exercise, energy utilization in muscles increases and the oxygen availability decreases. In such situations muscle cells produce energy by anaerobic
respiration and lactic acid is formed in the muscle cells.

Question 47.
How does butter become soft and puffy?
Answer:
Fermentation helps the batter rise, become lighter and increase in volume making it double in size, thicker and fluffier.

Do Not Damage The Respiratory System

Question 48.
………. is an army in the lungs?
Answer:
Macrophages

Question 49.
……… is the specialized cells seen in the alveoli that engulf dust particles and germs.
Answer:
Macrophages

Question 50.
What are the instances that are harmful to lungs?
Answer:
Dust, germs, chemicals, etc. which are contained in the air we breathe in.

Question 51.
Find out the protective mechanism of the respiratory system? Explain.
Answer:
Nose, nasal cavity:

• Small hairs prevent dust and germs from entering the lungs.
• Dust particles and germs get entangled in the mucus secreted by the mucous membrane.
• Lysozyme present in the mucous destroys germs.
• Ciliary cells transport mucus that contains dust and germs to the pharynx and from there to the digestive tract.

Trachea:

• The germs and dust particles get entangled in the mucus secreted by the mucous cells(Goblet cells) and mucus glands seen throughout the tracheal wall.
• The cilia of ciliary cells in the tracheal wall move the mucus containing dust and germs to pharynx.

Alveoli:

• Macrophages, the specialized cells seen in the alveoli, engulf dust particles and germs.

Question 52.
‘Smoking is injurious to health’ Rekha reminded Rajeev. Do you agree with Rekha? Justify your answer.
Answer:
I agree with Rekha’s statement. Smoking is a bad habit that harmfully affects the human race. It not only affects the person who smokes but also affects the nearby persons who breathe the smoke. Carcinogens present in tobacco cause lung cancer. Alveoli rupture due to the loss of elasticity by the deposition of toxic substances contained in tobacco. This reduces the respiratory surface and reduces vital capacity. This stage is emphysema. The tar, carbon monoxide, etc. in tobacco leads to the deposition of mucus and the swelling of lungs due to the proliferation of germs in the alveoli. This stage is known as bronchitis.

Question 53.
Prepare a poster relating to anti-smoking
Answer:

Vital Capacity

Question 54.
What do you mean by Tidal volume?
Answer:
Tidal volume is the volume of air we breathe in and out during a normal breathing.

Question 55.
What is vital capacity?
Answer:
Vital capacity is the volume of air that can be breathed out by forceful expiration after maximum or forceful inspiration. ,

Question 56.
What can be taken as an indicator of normal and healthy respiratory capacity?
Answer:
Vital capacity

Question 57.
What is the vital capacity of men?
Answer:
It is about 4.5 liters

Question 58.
What is the vital capacity of women?
Answer:
about 3 liters

Respiration In Other Organism

Question 59.
Collect data on respiratory diversity in organisms and complete the table.
Answer:

Do Plants Breathe

Question 60.
State whether true or false.
Plants also utilize glucose for the production of energy.
Answer:
True

Question 61.
The oxygen needed for the oxidation of glucose is absorbed from ………….
Answer:
Atmospheric air

Question 62.
………. are the centers of exchange of gases in plants.
Answer:
Stomata

Question 63.
Exchange of carbon dioxide and oxygen takes place in stems and roots through ………….
Answer:
Lenticels

Question 64.
Prepare a poster for environment day observation.
Answer:
Plant trees
Plant generations

Let Us Assess

Question 65.
Reason for the diffusion of oxygen from alveoli to blood.
a) Low concentration of oxygen in blood.
b) As the walls of the alveoli and blood vessels are thin.
c) High concentration of oxygen in alveoli.
d) All of the above,
Answer:
d) All of the above.

Question 66.
Observe the two reactions given below
Reaction 1:
C₂H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + energy Reaction

a) Identify the process occurring in plants and in animals.
b) Which is the process that takes place only in plants?
Answer:
a) C₂H₁₂O₂ + 6O₂ → 6CO₂ + 6H₂O + energy

You can Download Structure of Atom Questions and Answers, Summary, Activity, Notes, Kerala Syllabus 9th Standard Chemistry Solutions Part 1 Chapter 1 help you to revise complete Syllabus and score more marks in your examinations.

Kerala State Syllabus 9th Standard Chemistry Solutions Chapter 1 Structure of Atom

Structure of Atom Textual Questions and Answers

Kerala Syllabus 9th Standard Chemistry Chapter 1 Question 1.
Explain the postulates of Rutherford model of atom?
Answer:

• An atom has a center called nucleus
• Compared to the size of an atom the size of the nucleus is very smell
• All the positively charged particles and most of the mass are concentrated in the nucleus of atoms.
• Negatively charged electrons revolve around the nucleus in circular path.
• This atom model is known as planetary model of atom because sun at the center is compared to the nucleus planets revolving around the sun is compared to electrons.

Kerala Syllabus 9th Standard Chemistry Notes Question 2.
Explain the limitations of Rutherford’s model of atom?
Answer:
According to James Clerk Maxwell’s electromagnetic theory, a charged body in circular motion continuously emits energy as radiations. Electrons which revolve around the nucleus are negatively charged. Hence while electrons revolve around the nucleus, they should emit electromagnetic radiations lose energy and come closer to the nucleus Finally the negatively charged electrons should collapse into the nucleus. But this does not happen in an atom. It Rutherford’s model failed to explain this.

9th Chemistry Notes Kerala Syllabus Question 3.
Explain Bohr model of atoms?
Answer:

• Electrons revolve around the nucleus in fixed paths called orbit or shells.
• Electrons in each shell have a definite energy hence shells are also called energy levels.
• As long as an electron revolves in a particular orbit its energy remains constant.
• The energy of the shell increases as the distance form the nucleus increases
• The shells.around the nucleus can be numbered from near the nucleus 1,2, 3,4…. or represented by the letters K, L, M, N

Kerala Syllabus 9th Standard Chemistry Guide Pdf Question 4.
Explain the discovery of chargeless particles too- within an atom?
Answer:
The actual mass of an atom should be equal to the sum of the mass of particles present in it. Scientists realized the fact that there is no relation between the total mass of particle, ie., electrons, and protons in an atom and the actual mass of an atom.

From this, it can be inferred that nucleus may contain neutral particles having mass equal to that of protons predicted by Rutherford. In 1932 James Chad Wick-confirmed the presence of neutral particles within the nucleus of an atom. These particles are called neutrons. The mass of neutron is determined slightly higher than that of protons.

Fundamental particles of an atom

Answer:

Mass Number and Atomic Number

Kerala Syllabus 9th Standard Notes Chemistry Question 5.
Which are the fundamental particles whose masses are mainly responsible for the mass of an atom?
Answer:
Protons and neutrons

Kerala Syllabus 9th Standard Chemistry Solutions Question 6.
Is there any relation between the total number of protons and neutrons in an atom and its mass?
Answer:
Same

Chemistry Notes Class 9 Kerala Syllabus Question 7.
Define mass n u m ber of an atom?
Answer:
The total number of protons and neutrons in an atom is called the mass number it is represented by the Letter ‘A’.

Kerala Syllabus 9th Standard Chemistry Notes Pdf Question 8.
Which is the particle of an atom- that has the possibility of changing of position, which can be exchanged when atoms rub against each other collide or chemically react with other atoms?
Answer:
Electrons

9th Class Chemistry Notes Kerala Syllabus Question 9.
Atoms are electrically Neutral” Justify it?
Answer:
The number of protons and electrons are equal in an atom.

Chemistry 9th Class Notes Kerala Syllabus Question 10.
Define atomic number of an element?
Answer:
The total number of protons in an atom is called atomic number it is represented as Z.

Chemistry Notes For Class 9 Kerala Syllabus Question 11.
Which are the particles whose numbers you can find out if you know the atomic number of an atom?
Answer:
No. of protons and electrons

Kerala Syllabus 9th Standard Chemistry Notes English Medium Question 12.
Why?
Answer:
Because the number of protons and electrons in an atom are equal.

Hsslive Guru Chemistry Class 9 Kerala Syllabus Question 13.
How to write the mass number and atomic number of an element if the symbols are known?
Answer:
Mass number on the left side above the symbol and atomic number on the left side below the symbol.
Eg. Sodium atom can be represented as \(\begin{array}{l}{23 \mathrm{Na}} \\ {\text { 11 }}\end{array}\)

Question 14.
Symbol of certain atoms are given in the table complete the table

Answer:

Electronic Configuration in Atom

Question 15.
Analyze the electronic configuration of atoms of element 1 – 18 in the following table:

Question 16.
What is maximum electrons that can be accommodated in K shell?
Answer:
2

Question 17.
What is maximum electrons in that can be accommodated in L shell?
Answer:
8

Rules for filling electrons in shells
1. The maximum electrons that can be accommodated in any given shell can be calculated by the equation 2n² where ‘n’ represents the number of shells.

2. Shells with lower energy will be filled with maximum number of electrons first. Thereafter shells having higher energy will get filled.
3. The maximum number of electrons that can be contained the outermost shell of an atom is 8.

Question 19.
Write down the electron configuration of the following elements Draw its Bohr model.

Answer:
1. \(\frac{14}{7} \mathrm{N}\) Atomic No.: -7
Electron configuration – 2, 5

2. \(\frac{24}{12} \mathrm{Mg}\) Atomic No.: 12
Electron configuration – 2, 8,2

3. \(\frac{32}{16} \mathrm{S}\) Atomic No.: -16
Electron configuration – 2, 8,6

Question 20.
Bohr model of atoms of certain elements are given below (Fig 1.9) asess their electronic configuration.

Question 21.
The symbol of the aluminum atom is \(\frac{27}{13} \mathrm{AI}\) Bohr model of the atom is given in Fig. 1.10 analyze these and complete the table

Answer:

Isotopes

Question 22.
You would have understood that the number of protons in an atom determines the element. Analyze the given Bohr models.

Question 23.
Complete the table providing details related to these atoms.

Answer:

Question 24.
Among these atoms which is the particle that is differs in numbers?
Answer:
Neutrons

Question 25.
Which inferences can you arrive at when you examine the atomic number and mass number of these elements?
Answer:
They are atoms of the same element with same atomic number. But different mass numbers.

Question 26.
What is meant by Isotopes?
Answer:
Isotopes are atoms of the same element with same atomic number but different mass number.

Question 27.
Which isotope of Hydrogen is used in atomic reactors?
Answer:
Deuterium

Question 28.
Write the isotopes of carbon?
Answer:

Question 29.
Which are the isotopes is used as tracers for identifying the nutrient exchange in plant?
Answer:
Phosphorous-31

Question 30.
Which isotope of Uranium is used in atomic reac¬tors as fuel?
Answer:
Uranium – 235

Question 31.
What is meant by isobar?
Answer:
Isobars are atoms having the same mass number but different atomic number
e.g. \(_{20}^{40} \mathrm{Ca}, \quad_{18}^{40} \mathrm{Ar}\)

Question 32.
Symbols of certain isotopes are given in table 1.9. Complete the table writing their atomic number, mass number, number of protons, electrons and neutrons.

Answer:

Let Us Assess

Question 1.
Name of some scientists and their contributions are given in in the following table. Match them suitably in the chronological order.

Answer:

Question 2.
Atomic number of an atom Z=17, Mass number 35.
a) Find the number of protons, electrons, and neutrons in the atom.
b) Write the electronic configuration of different shells.
c) Draw the Bohr model of atom.
Answer:
a) No. of protons -17
No. of electrons -17 No. of neutrons = 35 – 17 =18
b) 2, 8, 7

Question 3.
The mass number of an atom is 31. The M shell of this atom contains 5 electrons.
a) Write the electronic configuration.
b) What is the atomic number of this atom?
c) How many neutrons does this atom have?
d) Draw the Bohr model of the atom.
Answer:
a) 2, 8, 5
b) 15
c) 31 – 15 = 16

Question 4.
Bohr models of atoms A, B, C, D are given (Symbols are not real).
a) Write the atomic number, mass number and electronic configuration of the atoms.
b) Among these, which are isotopes? Why?



Answer:

Question 5.
Symbols (not real symbols) of some atoms are given.
\(_{17}^{8} \mathrm{P}, \quad_{40}^{18} \mathrm{Q}\)\(_{8}^{16} \mathrm{P}, \quad_{40}^{20} \mathrm{R}\)
a) Find the atomic number and mass number of these elements.
b) Which among these are isotopic pairs?
c) Draw the Bohr model of atom Q
Answer:
a)
b) Isotopes P, R

Structure of Atom Model Questions and Answers

Question 1.
Write the atomic number of an atom is 18 and mass number is 40
a) Find the number of protons, electrons, and neutrons in the atom.
b) Write the electronic configuration of different shells
c) Draw the Bohr model of the atom
Answer:
a) No. of protons -18
No. of electrons -18
No. of neutrons – 40 – 18 = 22
b) 2, 8, 8

Question 2.
The 3^rd shell ie. M shell of an atom contains 3 electrons. The mass number is 27.
a) Write the atomic number of this atom.
b) Write the electronic configuration.
c) How many electrons, neutrons does this atoms have?
d) Draw the Bohr model of atom?
Answer:
a) 13
b) 2, 8, 3
c) No. of protons -13 No. of electrons -13
No. of neutrons – 27 – 13 = 14

Question 3.
Write the uses of the following isotope
a) Carbon – 14
b) Phosphorous – 31
c) Iodine – 131 and cobalt 60
d) Uranium – 235
Answer:
Isotope Uses
a) Carbon-14 — Used to determine the age of fossils and prehistoric objects
b) Phosphorous-31 — Used as tracers for identifying the nutrient exchange in plants
c) Iodine -131 or cobalt – 60 — In medical sciences for the diagnosis and treatment of cancer and tumor
d) Uranium – 235 — Used in atomic reactor as fuel

Question 4.
Write the electronic configuration and draw the Bohr model?
Answer:
1) \(_{35}^{17} \mathrm{CI}\)
Electron configuration : 2, 8, 7
No. of neutrons = 35 – 17 = 18

2) \(_{23}^{11} \mathrm{Na}\)
No. of neutrons = 23 – 11 = 12
Electron configuration -2,8,1

Question 5.
\(\frac{12}{6} \mathrm{C}, \frac{14}{6} \mathrm{C}\)
Find the isotopes and isobars pairs among them. Justify it?
Answer:
\(\frac{40}{18} \mathrm{Ar}, \frac{40}{20} \mathrm{Ca}\) are Isotopes. Because they are atoms of the same element with same atomic number but different mass numbers.
1840Ar, 2040Ca are Isobars because they are atoms of different elements with different atomic numbers but same mass number.

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Kerala State Syllabus 9th Standard Maths Solutions Chapter 10 Real Numbers in Malayalam Medium

Real Numbers Questions and Answers in Malayalam

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Adisthana Padavali Malayalam Standard 9 Solutions Answers Guide Notes

Adisthana Padavali Malayalam Standard 9 Guide

Unit 1 Pookal Okkeyum Vakkukal Kumpol

• Chapter 1 Ate Prarthana
• Chapter 2 Haritha Mohanam
• Chapter 3 Vellachattattinte Idimulakkam

Unit 2 Kalcayute Sangitam

• Chapter 1 Kotiyerram
• Chapter 2 Velichathinte Viralukal

Unit 3 Oru Kudanna Velichamayi

• Chapter 1 Ajagajantaram
• Chapter 2 Saphalamee Yathra
• Chapter 3 Kaviyum Samuhajivi
• Chapter 4 Buddhante Upadesam

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