Manganese reacts with hydrochloric acid to produce manganese(II) chloride and hydrogen gas.
Mn(s)+2HCl(aq) → MnCl2(aq)+H2(g)
1. When 0.630 g Mn is combined with enough hydrochloric acid to make 100.0 mL of solution in a coffee-cup calorimeter, all of the Mn reacts, raising the temperature of the solution from 24.0 ∘C to 28.1 ∘C.
Find ΔHrxn for the reaction as written. (Assume that the specific heat capacity of the solution is 4.18 J/g∘C and the density is 1.00 g/mL.) (express answer in 3 sig figs)