The rise in temperature is 298.45 K - 298.0 K = 0.45 K. Energy released at constant volume due to combustion of 3.5 g of a gas = 2.5 × 0.45. Hence energy released due to combustion of 28 gram (i.e., 1 mole) of a gas = 2.5 × 0.45 × 28/3.5 = 9 KJ/mol.