A student has found the following results from an experiment

A student has found the following results from an experiment on an unknown ideal gas. The molecular weight, specific heat at constant volume and specific heat at constant pressure are 8.314 kg/kmol, 2 kJ/kg-K and 4kJ/kg-K, respectively.

Are these numbers possible? Please justify your answer with equation(s) and calculation(s).

Solution

Given Mol.wt = 8.314, Cv = 2, Cp= 4 . The gas constant of ideal gas is given by [R = (universal gas constant)/Mol.wt],

now we know that universal gas constant R\" = 8.314kg/kmol. therefore Gas constant of ideal gas is

R = R\"/Mol.wt or R = 8.314/8.314 =1 ie R= 1 .............(1)

and we know that

R= Cp - Cv

R= 4 - 2 ie R = 2............ (2)

from eqn 1 and 2 we get different value of gas constant R and so we conclude that the above data are not correct and these data are not possible.