When you add 0.295 g of sodium metal to an excess of hydrochloric acid, you find that 3070 j of heat are produced. what is the enthalpy of the reaction as written below?

Since the following can have this reaction:

2Na(s) + 2 HCl (aq) → 2NaCl(aq) + H2(g)

0.295 g Na = 0.295 / 23 = 0.0128 mol

0.0128 mol ---> 3070 J, so 2 mol Na ---> 3070 j / 0.0156 mol x 2 mol = 393589.74 j

"record the time to complete a chemical reaction" would most likely be part of a lab procedure.