When 0.969 g of CaO is added to 200.0 mL of 0.500 M HCl(aq), a temperature increase of 397C is observed.
Assume the solution's final volume is 200.0 mL, the density is 1.00 g/mL, and the heat capacity is 4.184 J/gC.
Delta Hrxn, for the reaction of
CaO(s) + 2H+(aq) Ca2+(aq) + H2O(l)
is ________________ kJ/mol.