| 1. | Safety |
| 2. |
Objectives/Overview |
| 3. |
Procedures |
| 4. | Observations |
|
5. |
Equipment |
| 6. | View
Techniques |
| 7. | |
| 8. | Calculations/Set-ups |
| 9. | Conclusions |
| 10. | Grading Scale |
|
11. |
Sample Report Forms |
|
11. |
Review Prelab Questions |
| 12. | Review Postlab Questions |
Experiment
7
Enthalpy
of Solution
POSTLAB QUESTIONS
SHOW SET-UP FOR ALL PROBLEMS
1. A student performs an experiment involving the neutralization of NH3(aq) with HCl(aq) using a coffee cup calorimeter having a heat capacity of 15.6 J/g °C. The student mixes 50.0 mL of 1.00 M HCl with 50.0 mL of 1.00 M NH3. The temperature of the reaction solution is found to increase 6.5°C. Assume that the heat capacities of the solutions are 4.184 J/g°C and that the densities of the solutions are 1.00 g/mL.
a) Determine the heat (J and kJ) evolved by the acid-base reaction.
b) Calculate the number of moles of HCl and the number of moles of NH3 used in the experiment.
c) Determine the molar heat of neutralization (kJ/mol) of NH3(aq) with HCl(aq). If the accepted value is -51.7 kJ/mol, determine the student's percent error.
2. Determine the heat capacity of a calorimeter if 75.15 kJ of heat causes the temperature of the calorimeter to rise from 21.04 °C to 28.54 °C.
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.
