Suppose that 31.4 J of heat is added to an ideal gas. The gas expands at a constant pressure of 1.40 × 104 Pa while changing its volume from 3.00 × 10-4 to 8.00 × 10-4 m3. The gas is not monatomic, so the relation Cp = 5/2 R does not apply.

(a) Determine the change in the internal energy of the gas.

(b) Calculate its molar specific heat capacity CP.