Question

Give reasons:
i) We should breathe through nose not through mouth
ii) Formation of clouds is a physical change.
iii) Is air a mixture or a compound.
iv) Mountaineers carry oxygen cylinders.

Answer 1

Answer:

4.mountaineers carry oxygen cylinders because they have some breathing problem at high altitude.

Answer 2

Explanation:

1.we should breathe through our nose not from the mouth because our nose has small hairs inside our nose which don't allow the dust particles to enter in our body. whereas in mouth their is no such protection and we can inhale many dust particles while breathing from our mouth and can cause many health diseases.

2.Formation of clouds is a physical change as it is phase transformation of water from liquid to gas during water cycle and then, gas to liquid. Hence, the physical property of water undergoes change in the formation of clouds.

3.Air is a mixture and not a compound because of following reasons: Air can be separated into its constituents such as oxygen, nitrogen etc. by fractional distillation of liquid air. Air shows the properties of all the gases present in it

4.Mountaineers carry an oxygen cylinder along with them. It is because when they climb mountains, as altitude increases, the amount of oxygen level in the atmospheric air decreases as trees are not found at higher altitudes. As a result, mountaineers suffer from dizziness.