Question

State whether the following statements are true or false.
(a) Air consists of a single substance.
(b) When water is poured into a glass, air is pushed out of the glass.
(c) Trees need oxygen for photosynthesis.
(d) When we exhale, we give out the carbon dioxide produced in the body.
(e) The amount of water vapour in the air is always the same.
(f) Nitrogen is required by plants to make proteins.
(g) Aircrafts fly in the ionosphere as there is less friction in this zone.
(h) One per cent of air contains carbon dioxide, argon, helium, argon and krypton-all of which are inert gases.
(i) LPG and CNG burn using oxygen gas and release carbon dioxide gas.
(j) Nitrogen in the air also helps in burning.

Answer 1

(a) False. Air is a mixture of gases.

(b) True.

(c) False. Trees need carbon dioxide for photosynthesis.

(d) True.

(e) False. Water vapour in atmosphere keeps on changing.

(f) True.

(g) False. They fly in stratosphere.

(h) False. Carbon dioxide is not an inert gas.

(i) True.

(j) False. Oxygen helps in burning.