Tag: is air present everywhere around us?

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Multiple choice evs atmosphere- wind importance of oxygen is air present everywhere around us? air as a natural resource

Which of the following statement is true?

  1. Hot air expands on heating.

  2. Hot air contracts on cooling.

  3. Cold air contracts on heating.

  4. None of the above.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Air is a mixture which is composed of several gases like oxygen 21%, nitrogen 78%, carbon dioxide 0.03% and water vapors. The air molecules are held by strong intermolecular forces. When air is heated up, the air molecules absorb the heat and the intermolecular forces between the air molecules become weak and its kinetic energy increases. The air molecules move apart and become less dense and thus they expand on heating.
So, the correct answer is option A.
Multiple choice evs atmosphere- wind importance of oxygen is air present everywhere around us? air as a natural resource

Choose the correct answer from the alternatives given.
The largest reservoir of nitrogen on earth is:

  1. soil

  2. oceans

  3. air

  4. granite rocks
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

It is true that 70% or so of the Air is nitrogen but that it needs to be the largest reservoir. Nitrogen is an essential part of most living organisms. Most of the bodily fluids and enzymes have nitrogen in a bonded form. This is true even in the case of plants. So, the correct answer is "Air".

Multiple choice chemistry air around us importance of oxygen is air present everywhere around us? air as a natural resource

Ozone hole means :

  1. thinning of the ozone layer

  2. a large sized hole in ozone layer

  3. small hole scattered in the ozone layer

  4. thickening of ozone in ozone layer
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

"Ozone hole" means thinning of the ozone layer.


The ozone hole is not technically a “hole” where no ozone is present but is actually a region of exceptionally depleted ozone layer.

Hence the option A is correct.

Multiple choice chemistry air around us importance of oxygen is air present everywhere around us? air as a natural resource

Choose the correct answer form the alternatives given.
Scuba divers are at high risk due to high concentration of dissolved gases while breathing air at high pressure under water. The tanks used by Scuba divers are filled with :-

  1. Air diluted with helium

  2. 02

  3. N

  4. A mixture of nitrogen and helium
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Scuba divers use a mixture of gases to avoid nitrogen narcosis and oxygen toxicity at high pressures. Helium is often used to dilute the mixture because it is inert and less soluble in blood than nitrogen.

Multiple choice chemistry air around us importance of oxygen is air present everywhere around us? air as a natural resource

The nitrogen molecules present in the air can be converted into nitrates and nitrites by :

  1. nitrogen fixation

  2. carbon fixation

  3. industries in the form of by ctprodu

  4. cereal plants
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The nitrogen molecules present in the air can be converted into nitrates and nitrites by nitrogen fixation.


Hence the option A is correct.