Ch - Air and Water

CBSE Grade 5 Ch  - Air and Water Practice Questions

Q1) What is the atmosphere.
 
Q2) Name the various layers of the atmosphere.

Q3) Name any three impurities that make water unfit for use.

Q4) The two types of impurities in water? Give examples.

Q5) Differentiate between sedimentation and decantation.

Q6) Differentiate between boiling and distillation.

Q7) List few examples where concept of air pressure helps in our everyday life.

Q8) Describe the different ways by which insoluble impurities can be removed from water.

Q9) Describe the different ways by which soluble impurities can be removed from water.

Q10) Describe the layers of atmosphere.

Q11) Name the layer of atmosphere

a) layer nearest to earth's surface
b) layer in which living things can breathe normally
c) layer in which jet planes fly
d) layer that fades into space
e) layer that extends to about 500 to 600 km above the earth. 
F) Meteors burn in this layer

Important Questions with Answer.

Question: What is the atmosphere?

Answer: Air is a layer around the earth. This layer is called the earth’s atmosphere.

Question: Name the various layers of the atmosphere.

Answer: The various layers of the atmosphere are:

  1. Troposphere
  2. Stratosphere
  3. Mesosphere
  4. Thermosphere
  5. Exosphere

Question: How does the atmosphere protect us from meteoroid hits?

Answer: The atmosphere protects us from meteoroid hits by burning them up in the mesosphere before they can hit the surface of the earth.

Question: What is air pressure.

Answer: The weight of air pushes everything around it in all directions is called air pressure.

Question: Name any three impurities that make water unfit for use.

Answer: The three impurities that make unfit for use are:

  1. Sand
  2. Mud
  3. Dirt

Question: The two types of impurities in water? Give examples.

Answer: The two types of impurities in water are:

  1. Impurities that dissolve in water are called soluble impurities.
  2. Eg: salt, sugar.
  3. Impurities that do not dissolve in water are called insoluble impurities.
  4. Eg: sand, mud

Question: Differentiate between sedimentation and decantation.

Answer:

Sedimentation: If the mixture of insoluble impurities. For e.g. mud and water is allowed to stand undisturbed in a beaker. After some time, the mud settles down at the bottom of the container as sediments. This processes is called sedimentation.

Decantation: Clean water obtained from the process of sedimentation can then be poured out into a separate container without disturbing the sediments. this process is called decantation.

Question: What is loading?

Answer: The rate of sedimentation can be increased by adding special chemicals like alum. This process is called loading.

Question: Differentiate between boiling and distillation.

Answer:

Boiling:

  1. In this process a liquid vaporized by heating it to its boiling point.
  2. In this process the valour is released into the atmosphere.
  3. It is a simple process and can be easily carried at home.
  4. Boiling can take place in a short time (for eg 10 mins).
  5. Boiling kills all the germs like bacteria, virus.
  6. Boiled water can be used for drinking.

Distillation:

  1. In this process soluble impurities are removed from a solution by evaporation and condensation.
  2. In this process the vapour is collected to cool it down and form a pure liquid.
  3. It is a complex process and cannot be carried at home.
  4. Distillation will occur in a long period of time. ( for eg 1-3 hrs).
  5. Distillation not only kill the germs but also kill all the minerals in water.
  6. Distilled water cannot be used for drinking as it has no muscles.

Question: Describe with examples how air pressure helps in our everyday life.

Answer: Air pressure helps us in our everyday life. We would not be able to do many things if there is no air pressure. some examples are:-

  1. Filling up fountain pens.
  2. Filling up a syringe.
  3. Drinking through a straw.
  4. Using droppers.

For example if we try to open a juice can and we make a small slit on one side, the juice will flow out slowly. But if we make another slit the juice will flow out rapidly. This happens because air enters the juice can from the second slit and air pressure pushes the juice out of the can.

Question: Describe the different ways by which insoluble impurities can be removed from water.

Answer: the different ways by which insoluble impurities can be removed from water are the following:

  1. Filtration
  2. Sedimentation and Decantation
  3. Loading

Floating:

In this process insoluble impurities are removed from water by passing the impure water through a filter paper. A circular piece of filter paper is taken and folded twice to make a cone and this is kept inside a funnel. A flask is kept below the funnel and the mixture is houred into the flask through the funnel. Sand is retained on the filter paper and clean water is obtained in the flask.

Sedimentation and Decantation:

  1. The mixture of insoluble impurities for example, (mud ) and water is allowed to stand undisturbed in a beakker.
  2. After some time the mud settles down at the bottom of the container as sediments. This process is called sedimentation.
  3. Clean water can then be poured out into a seperate container without disturbing the sediments. This process is called decantation.

Question: Describe the different ways by which soluble impurities can be removed from water.

Answer: The different ways by which soluble impurities can be removed from water are:

  1. Evaporation: In this process a solution containing soluble impurities like common salt or sugar is heated. After some time water will change into steam and the soluble impurity will be left behind in the container.
  2. Distillation: This process involves the following steps:
    (i) Impure water is taken in a round bottomed flask and heated.
    (ii) On heating, water changes into steam and the impurities are left behind. Whwn the steam through the condenser, it cools and turns into water (liquid).
    (iii)Pure water is collected in a flask.

Question: Describe the different ways by which water can be purified.

Answer: The different ways by which water can be purified are:

  1.     Boiling
  2.     Sedimentation and decantation
  3.     Distillation
  4.     Filtration
  5.     Chlorination

Chlorination: In this method chlorine is added to kill the germs in water. Chlorine tablets are also available in the market which can be used for this process.

Purification Of Water 

  1. Large impurities are removed by sedimentation and decantation. Alum is added to increase the rate of sedimentation (loading).
  2.  Finer impurities are removed by filtration.
  3.  Chlorine is added to kill germs (chlorination).
  4.  Water is stored in big storage tanks to supply to users.
  5.  Clean water is supplied to users.

Question: Describe the layers of atmosphere.

Answer: The different layers of atmosphere are:

 

Troposphere:

 

    This is the first layer of atmosphere.

    The weather phenomenon like rain, cloud formation and wind happens in this layer.

    Living things can survive in this layer.

 

Stratosphere:

 

    This is the second layer of atmosphere.

    Ozone layer is present in stratosphere which protect us from harmful UV rays radiations that can cause health problems like skin cancer

    Many jet airplains fly in this layer.

 

Mesosphere:

 

    This is the third layer of atmosphere.

    It protect us from meteroids by burning them before they can reach the surface of the earth.

 

Thermosphere:

 

    It is the fourth layer of atmosphere.

    Space shuttles can revolve in this layer.

 

Exosphere:

 

    It is the last layer of atmosphere.


Q11) Name the layer of atmosphere

a) layer nearest to earth's surface -Troposphere
b) layer in which living things can breathe normally - Troposphere
c) layer in which jet planes fly - Stratosphere
d) layer that fades into space - Exosphere
e) layer that extends to about 500 to 600 km above the earth. - Thermosphere
F) Meteors burn in this layer - Mesosphere