Sania:

I understand you to say that you know the “Normal” volume of a gas and want to know the actual volume at a specific temperature and pressure (both different from “Normal” conditions). If that is what you mean, then you can use the Ideal Gas Equation PV = nRT – but only if you know the molecular weight of the gas. A more conventional method of converting the volume is to use the result of combing simultaneous equations:

V_{2} = V_{1} (Z_{2}/Z_{1}) (P_{1}/P_{2}) (T_{2}/T_{1})

Where,

V_{2} = gas volume at the new condition, m^{3};

V_{1} = “Normal” gas volume, m^{3};

P_{1} = 1.0 atm, absolute;

P_{2} = pressure at the new condition, atm., absolute;

T_{1} = 273 ^{o}K;

T_{2} = absolute temperature at new condition, ^{o}K.

The above equation is derived dividing one of the following equations by the other:

P_{2} V_{2} = Z_{2} n R T_{2}

P_{1} V_{1} = Z_{1} n R T_{1}

I hope this helps you out.