Magnesium metal reacts with hydrochloric acid according to the balanced equation:

In an experiment to determine the enthalpy change for this reaction, 0.158 g of Mg metal is combined with enough HCl to make 100.0 mL of solution in a coffee-cup calorimeter. The HCl is sufficiently concentrated so that the Mg completely reacts. The temperature of the solution rises from 25.6 °C to 32.8 °C as a result of the reaction. Find ΔH_rxn for the reaction as written. Use 1.00 g/mL as the density of the solution and C_{s, soln} = 4.18 J/g · °C as the specific heat capacity of the solution.

Transcribed Image Text:

Mg(s) + 2HCl(aq) MgCl₂(aq) + H₂(8)