Main Components

Q.

Why do living things need air?

Q.

How do humans use nitrogen?

Q. Is gun powder a homogeneous or a heterogeneous mixture? Explain.

Q.

Write two properties of air.

Q.

Name the gases which are present in the air. Also give the percentage of oxygen and nitrogen in the air.

Q.

Nitrogen dioxide reacts with carbon dioxide to form nitric acid.

1. False

2. True

Q. List any five activities which are possible due to the presence of air. [5 MARKS]

Q.

$\mathrm{Oxygen}$ is a monoatomic gas.

1. True
2. False

Q.

Name the electromagnetic spectrum which cause greenhouse effect.

Q.

Air is a mixture of elements and compounds.

1. True
2. False

Q.

Statement I: Policemen regulating traffic at a crowded crossing often wear a mask.

Statement II: Mask filters carbon dioxide and sends pure oxygen inside.

1. Statement I is True and Statement II is not the correct explanation.

2. Statement I is True and Statement II is false

3. Statement I is True and Statement II is the correct explanation.

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

Q.

Question 6

Which of the following components of air is present in the largest amount in the atmosphere?

a) Nitrogen

b) Oxygen

c) Water vapour

d) Carbon Dioxide

Q. Mention five important properties of air. [5 MARKS]

Q.

Carbon monoxide is heavier than air.

1. True
2. False

Q.

A group is given with four examples, write down the category of the group and identify the odd one out.

Sulphur dioxide, Carbon monoxide, Oxygen, Nitrogen dioxide.

Q. What is nitrogen gas used to manufacture on large scale?

Q.

Which bacteria are used in soil and agricultural microbiology?

Q. What is carbon dioxide's content in air

Q.

The composition of air was discovered by Lavoisier.

1. True
2. False

Q. The cover of air around the earth is known as_____.

1. Biosphere
2. Hydrosphere
3. Atmosphere
4. Lithosphere

Q.

A list of words is given in a box. Use appropriate words to fill up the blanks in the following statements.

[Air, oxygen, wind, water vapor, mixture, combination, direction, road, bottles, cylinders]

Air is a ______ of some gases.

Q. Explain the following observation very briefly.
Breathing through mouth may harm you.

Q.

Nitrogen is used in chips packets because it has non-oxidative properties.

1. The agents called antioxidants prevent oxidation of oils and fats in food.

2. Nitrogen is used to flush bags of chips beacuse it slows down the oxidation of chips.

Q.

The most abundant constituent of air is

1. Oxygen

2. Nitrogen

3. Water vapour

4. Impurities

Q. Why can we not see air even though it is counted as a material and a homogeneous mixture?

Q.

Statement I: Policemen regulating traffic at a crowded crossing often wear a mask.

Statement II: Mask filters carbon dioxide and sends pure oxygen inside.

1. Statement I is true and statement II is false

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

3. Both statements are true

4. Both statements are false

Q. Which of the following gases burns in air?

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

Q. Evaporation is slower when wind blows faster.

1. True
2. False

Q.

How is the balance of oxygen and carbon dioxide maintained in the atmosphere?

Q.

Air is required only for respiration and photosynthesis.

1. True
2. False