The temperature of 5 mol of a gas which was held at constant volume was changed from 100^oC to 120^oC. The change in internal energy was found to be 160 J. The total heat capacity of the gas at constant volume will be equal to : 

8 J/K

At constant volume the total energy will be utilized in increasing the temperature of gas :

i.e. \((\Delta Q)_v = \mu C_v \Delta T = \mu C_v (120-100) = 160\)

\(\Rightarrow \mu C_v = \frac{160}{20} = 8\) J/K