Manganese reacts with hydrochloric acid to produce manganese(II) chloride and hydrogen gas.
Mn(s) + 2HCl(aq) → MnCl2 (aq) + H2(g)
When 0.605 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 23.7 °C to 29.2 °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 your answer using three significant figures.