Manganese reacts with hydrochloric acid to produce manganese(II) chloride and hydrogen gas:

When 0.625 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 23.5 °C to 28.8 °C. Find ΔH_rxn 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.)

a) -195 kJ 

b) -3.54 kJ 

c) -1.22 kJ 

d) -2.21 kJ

Transcribed Image Text:

Mn(s) + 2 HCI(aq) → MnCl₂(aq) + H₂(8)