Experiment 8
Enthalpy of Combustion

A double-sided, styrofoam coffee cup of known heat capacity (determined in Experiment 7) will serve as a calorimeter. The calorimeter and a temperature probe will be used to measure the heat changes resulting from the reaction of two chemicals, magnesium metal and magnesium oxide, with 1.0 M hydrochloric acid solution. Knowing the heat capacity of the calorimeter, the mass of solution, specific heat of the solution, and the change in temperature resulting from the reactions, the student will calculate enthalpies, DHº_rxn, for each of the reactions. The student can then use Hess' Law to combine the experimental enthalpies with the enthalpy of a third known reaction,
H₂(g) + ½O₂(g) ----> H₂O(l), to calculate an experimental value for the heat of combustion of magnesium metal, DHº_comb.

NOTE: Pre-lab questions are to be completed and submitted as part of the lab report. They will be scored as a pre-lab quiz.