A quantity of 2.00 ( 102 mL of 0.862 M HCl is mixed with 2.00 (102 mL of 0.431 M Ba(OH)2 in a constant-pressure calorimeter of negligible heat capacity. The initial temperature of the HCl and Ba(OH)2 solutions is the same at 20.48°C. For the process
H+(aq) + OH-(aq) -→ H2O(l)
The heat of neutralization is 256.2 kJ/mol. What is the final temperature of the mixed solution?