Question

Specific heat capacity of a monoatomic gas at constant volume is 315J/kgK and at constant pressure is 525J/kgK . Find molar mass of gas in gram.

Answer 1

Dear Student,

Suppose molar mass = x g/mol
specific heat at constant volume = Cv = 315 J/kg.K = 0.315 J/g.K = (0.315x) J/mol.K
specific heat at constant pressure = Cp = 525 J/kg.K = (0.525x) J/mol.K
For monoatomic gas, Cp - Cv = R
0.525x - 0.315x = R
0.210x = 8.314
x = 39.59 g/mol
​Molar mass = 39.59 g/mol

​Regards