Air Is Everywhere

Q.

Question 4

Mountaineers carry oxygen cylinders with them because :

a) There is no oxygen on high mountains.

b) There is deficiency of oxygen on mountains at high atltitude.

c) oxygen is used for cooking.

d) oxygen keeps them warm at low temperature.

Q.

Question 1

Which of the following statements is incorrect?

a) All living things require air to breathe

b) We can feel air but we cannot see it.

c) Moving air makes it possible to fly a kite.

d) Air is present everywhere but not in soil.

Q. The activity which show " air contains water vapour" can you please explain that....

Q.

Question 5

Boojho took an empty plastic bottle, turned it upside down and dipped its open mouth into a bucket filled with water. He then tilted the bottle slightly and made the following observations.

(i) Bubbles of air came out from the bottle.
(ii) Some water entered the bottle.
(iii) Nitrogen gas came out in the form of bubbles and oxygen got dissolved in water
(iv) No bubbles formed, only water entered the bottle.

Which observations is /are correct?

a) (i) and (ii) only

b) (iv) only

c) (iii) and (iv)

d) (i) only

Q.

Air at high altitude has a higher percentage of oxygen as compared to that at low altitude.

1. Ocean

2. Caves

Q.

Differentiate between wind and string type musical instruments

Q.

28 List some uses of oxygen.

Q.

Which gas is required for combustion?

1. Oxygen

2. Nitrogen

3. Carbon dioxide

4. Hydrogen

Q.

Lump of cotton shrink in water because

1. Water does not occupy any space.

2. Air present in lump of cotton is replaced by water which occupies less space.

3. Space occupied by water is more than that of the space occupied by air.

4. Air doesn't occupy space but water does.

Q.

Question 9.4

State whether the following statements are true or false. If false, correct them.

Air does not occupy any space.

Q.

When we heat water, we find bubbles coming from it. This shows that

1. water contains air.

2. air contains water

3. water itself converts into bubbles.

4. water contains dissolved minerals.

Q.

The process of burning a substance in the presence of oxygen is called ___.

1. combustion

2. decomposition

3. respiration

4. condensation

Q. Why the animals living deep inside the soil come out during heavy rains?

Q.

What is rusting?

Q.

Is fire 🔥 living or nonliving

Q. The correct ascending order of gases as per their composition in air is:

1. hydrogen < oxygen < nitrogen
2. nitrogen < hydrogen < oxygen
   
3. oxygen < carbon dioxide < nitrogen
4. oxygen < carbon dioxide <hydrogen

Q.

Question 19.2

Paheli kept some water in a beaker for heating. She observed that tiny bubbles appeared before the water started to boil. She boiled the water for about 5 minutes and filled it in a
bottle up to the brim and kept the bottle air tight till it cooled down to room temperature.
Do you think tiny bubbles will appear on heating the water taken out from the bottle? Justify your answer.

Q.

Question 3

What is not true about air?

a) It makes the windmill rotate.

b) It helps in the movements of airplanes.

c) Birds can fly due to the presence of air.

d) It has no role in the water cycle.

Q.

Question 8

Usha took a lump of dry soil in a glass and added water to it till it was completely immersed. She observed bubbles coming out. The bubbles contain

a) Water vapour

b) Only oxygen gas

c) Air

d) None of these

Q. Arrange the following gases in ascending order of their percentages in the air.

1. Oxygen < Nitrogen < Hydrogen
2. Nitrogen < Hydrogen < Oxygen
3. Nitrogen < Oxygen < Hydrogen
4. Hydrogen < Oxygen < Nitrogen

Q. _______ gas is present in air in a very small quantity and is important for plants.

1. Hydrogen
2. Carbon monoxide
3. Nitrogen
4. Carbon dioxide

Q.

Write any four uses of oxygen?

Q.

Name the three categories of musical instruments.

Q.

Usha took a lump of dry soil in a glass and added water to it till it was completely immersed. She observed bubbles coming out. The bubbles contain:

1. Water vapour

2. Oxygen gas

3. Air

4. None of these

Q. Which property of nitrogen is responsible for its extensive use in the food packaging industry?

1. Colourless
2. Odourless
3. Inert
4. Tasteless

Q.

When a person's clothes catch fire, he or she is wrapped in a thick blanket so as to

1. cut off the nitrogen supply.

2. keep the body cool.

3. cut off the inert gas supply.

4. cut off the oxygen supply.

Q.

Question 17.3

Explain the following observations very briefly

An empty glass in fact is not empty.

Q.

Statement I: When water is heated, we see bubbles in it.

Statement II: The bubbles are due to air present inside the water.

1. Statement I is true and statement II is the correct explanation.

2. Statement I is true and statement II is not the correct explanation.

3. Statement I is rrue and statement II is false.

4. Statement I is false and statement II is true.

Q.

91 We are able to see air but we cannot feel its presence. Is it correct? If not, correct it?

Q. Which amongst the following does not contain air in it?

1. A glass of water
2. A deflated ballon
3. A sponge doll
4. An empty jar