Using data from the following reactions and applying Hess's law, calculate the heat change for the slow reaction of zinc with water (answer must be in kJ/mol Zn):
Zn(s) + 2 H2O(l) ----> Zn^2+(aq) + 2 OH-(aq) + H2(g) (ΔHrxn = ?)
H+(aq) + OH-(aq) ----> H2O(l) (ΔHrxn,1 = -56 kJ/mol H2O)
Zn(s) ----> Zn^2+(aq) (ΔHrxn,2 = -153.9 kJ)
1/2 H2(g) ----> H+(aq) (ΔHrxn,3 = 0.0 kJ)