The constant pressure molar heat capacity, C_{p,m}C p,m ​ , of methane gas, CH_4CH 4 ​ , is 35.31\text{ J K}^{-1}\text{ mol}^{-1}35.31 J K −1 mol −1 at temperatures close to 298\text{ K}298 K. Calculate the enthalpy change when 1.6\text{ kg}1.6 kg of methane gas is heated from a temperature of 280\text{ K}280 K to 320\text{ K}320 K.