One mole of a gas occupies 22.4 lit at N.T.P Calculate the difference between two molar specific heates of the gas . J = 4200 J / K cal :

Options

A. 2.378 k cal / kmol K
B. 3.028 k cal / kmol K
C. 1.979 k cal / kmol K
D. 4.569k cal / kmol K

Answer

C

Explanation

V = 22.4 litre = `22.4 xx10^(-3) m^3` ,
J = 4200 J/K cal by ideal gas equation for one mole of a gas.
`R=(PV)/T`
`=(1.013xx10^5xx22.4xx10^(-3))/273`
`C_P-C_V=R/J=(1.013xx10^5xx22.4)/(273xx4200)`
`=1.979kcal //kmolK`