When 0.712 g of Ca metal is added to 200.0 mL of 0.500 M HCl(aq), a temperature increase of 116C 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.
(Note: Pay attention to significant figures. Do not round until the final answer.)
The molar heat of reaction, H rxn, for the reaction of

You didn't complete the question.

If I assume the reaction is
Ca + 2HCl ==> CaCl2 + H2
Then heat rxn = mass x specific heat x delta T.
That will be delta Hrxn for 0.712 g Ca. If you want J/g or kJ/g leave it like that, if you want kJ/mol multiply kJ/g x molar mass Ca.