when 1L of 1M Ba(NO3)2 solution at 25 celsius is mixed with 1 L of 1M Na2SO4 solution at 25 celsius in a calroimeter, the white solid BaSO4 forms and the temperature of the mixture increases to 28.1 celsius. assuming that the calorimeter absorbs only a negligible quantity of heat capacity of the solution is 4.18J/celsius.g and that the density of the final solution is 1 g/mL, calculate the enthaply change per mole of BaSO4.