An experiment is performed to measure the molar heat capacity of a gas at constant pressure using Regnault's method. The gas is initially contained in a cubical reservoir of size ` 40 cm xx 40 cm xx 40 cm xx at 600 kPa at 27^0C`. A part of the gas is brought out, heated to 100^0C and is passed through a calorimeter at constant pressure. The water equivalent of the calorimeter and its contents increases from `20^0C to 30^0C` during the experiment and the pressure in the reservoir decresases to `525 kPa`. Specific heat capacity of water =`4200 J kg^(-1) K^(1). Calculate the molar heat capacity Cp from these data.