Experiment 8

1.	Safety
2.	Objectives/Overview
3.	Procedures
4.	Observations
5.	Equipment
6.	View Techniques A. Calibration of Temperature Probe B. Enthalpy of Combustion of Magnesium C. Temperature Extrapolation from Graph
7.	Waste Disposal/Clean-up
8.	Calculations/Set-ups
9.	Conclusions
10.	Grading Scale
11.	Review Prelab Questions
12.	Review Postlab Questions

Experiment 8
Enthalpy of Combustion

POSTLAB QUESTIONS

SHOW SET-UP FOR ALL PROBLEMS

1. Use the following reactions and enthalpies of the reactions to determine the enthalpy for the reaction below:

NaOH(s) ----> Na⁺(aq) + OH^-(aq)

Na⁺(aq) + OH^-(aq) + H⁺(aq) + Cl^-(aq) ---> H₂O(l) + Na⁺(aq) + Cl^-(aq)

DH = -101 kJ/mol

NaOH(s) + H⁺(aq) + Cl^-(aq) ----> H₂O(l) + Na⁺(aq) + Cl^-(aq)

DH = -56.8 kJ/mol

2. Determine the molar enthalpy of reaction if 75.15 kJ is absorbed by the solution plus calorimeter when 0.639 g of compound X is reacted. The molar mass of compound X is 83.45 g/mol.

3. A student observes that the temperature rises slowly during the first ten minutes of the experiment (before reaction begins). Explain why the temperature is rising during this time.