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Under standard conditions (pressure 1 atm (101325 Pa) and temperature 298,

3
15 К or 25 °С) the molar volume of gas is not equal to 22, 4 and 24, 4 dm /mol.
The ratio of the mass of a certain volume of one gas to a mass of the same

volume of another gas (taken under the same conditions) is called the relative

density of the first gas after the second. D
1 2

If the volumes of gases that are compared with each other are the same, then

the relative density is determined by the formula:

where m 1 and m 2 – masses of equal volumes of gases 1 and 2 at the same

temperature and pressure.

Accordingly, we can write that:

where M 1 and M 2 are the molar masses of gases 1 and 2.

where ρ 1 and ρ 2 - density of gas 1 and gas 2.

Thus, the density of different gases, taken under identical conditions,

proportional to their molar masses

If the conditions are different from the normal ones, the Clapeyron-

Mendeleev equation is used to calculate the gas parameters:

where M - is the molar mass of gas, g / mol;
m - gas mass, g;

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