Guide
1
gas regardless of its composition, has three main parameters: the mass, volume and density.In most applications operate on a so-called ideal gas, so they must rely only on the condition given in the mass, pressure and temperature.For example, in the problem can be specified nitrogen gas N2 with a temperature of 60 degrees, a pressure of 30 kPa and a mass of 0.05 g Knowing these three parameters and gas composition, according to the equation Mendeleyev-Clapeyron can find its scope.To do this, you must alter the equation as follows:

pV = mRT / M.

implement further conversion formula, get the amount of nitrogen:

V = mRT / pM.

the molar mass M can be found on Table D.
Mendeleev.In nitrogen, it is 12 g / mol.Then:

V = 0,05 * 12 * 8.31 * 333/30 * 12≈4,61.
2
If you know the volume under normal conditions, and the volume under different conditions is desired, apply the laws of Boyle and Gay-Lussac:

pV / T = pnVn / Tn.

In that case, convert the formula as follows:

pV * Tn = pnVn * T.

From volume V is:

V = pnVn * T / p * Tn.

index n denotes the value of a parameter under normal conditions.
3
If we consider the volume of gas from the thermodynamic point of view, we can see that the gases may act forces, due to which the volume changes.The pressure of gas is constant, which is characteristic of isobaric processes.During such processes, the volume changes from one value to another.They can be described as V1 and V2.In the context of a number of problems described by some gas, which is under the piston in the vessel.Upon expansion of the gas piston is moved by a distance dl, whereby the work is carried out:

A = pdV = p (V2 -V1).

This formula relates the change in gas volume and performance.As is known, if a given final volume V2, then we can find the initial volume V1:

V1 = pV2-A / p.
4
Finally, the most easy to find the volume of gas from two other physical parameters - mass and density.If the conditions specified gas with a density and mass, its volume should be calculated according to the formula:

V = m / ρ.

Each gas has a particular density, as with any solid or liquid substance.Therefore, finding a volume of gas in the first place it is necessary to consider this option.