The dissociation of I2 can be monitored by measuring the total pressure, and three sets of results are as follows: T/K 973 1073 1173 100p/atm 6.244 7.5 9.181 104n 2.4709 2.4555 2.4366 where n is the amount of I atoms per mole of I2 molecules in the mixture, which occupied 342.68 cm3. Calculate the equilibrium constants of the dissociation and the standard enthalpy of dissociation at the mean temperature.