The volume of a gas at constant T and P is directly proportional to the amount of the gas, which is just the number of moles, n.

V = an

But the number of moles n is just the mass divided by the molecular weight;

n = g/MW

Where g is the number of grams and MW is the molecular weight.

Combining these equations gives:

V = a*g/MW

This says we can relate the volume, mass, and molecular weight of gases if we keep the temperature and pressure constant.

(c) Copyright 2000. All rights reserved.