Question

Which is heavier nitrogen or air?

Answer 1

We know that the air is a mixture of gases of Nitrogen, oxygen, carbon dioxide etc. because the presence of these gases makes the air heavy. These gases increase the air density. The percentage of nitrogen, oxygen on an average is $80$ and $20$ percent.

Complete answer:
Here, first of all, we will see the definition of atomic mass. Then calculate the atomic mass of given compounds. Assuming that air consists mainly of nitrogen 78%. The Gases which have less atomic mass than that of air will be lighter than the air. The constituent of the atmosphere is a mixture of gases. The prominent ones are Nitrogen, Oxygen, Argon, Carbon dioxide. Hydrogen, Helium, and other noble gases are present in very insignificant proportions. Water vapor is also present at an average of one percent at sea level. These are mainly the by-products of life that the Earth itself sustains. The contribution of Nitrogen gas in the composition of Earth's atmosphere is about seventy-eight 78%
The density is just the molecular weight of the gas, divided by the volume of a given number of molecules. Since a given number of molecules always takes up the same volume for a gas, the higher the molecular weight, the heavier the gas is or the heavier the density. We have been asked about the gas which is heavier than air. So, for that we need to calculate the density of the gas. The density of a gas is roughly proportional to its molecular weight. Air has an average molecular weight of about $29\text{ }g/mol,$ so any gas with a molecular weight heavier than this will be denser than air. Air is heavier than nitrogen. Pure nitrogen is 3% lighter than air.

Note:
Remember that when calculating the weight of dry air molar mass is considered and calculated other than density or vapor density. Also, while calculating the density of air use the formula: the mass per unit volume of earth’s atmosphere.