Lab 8
Chemical Equilibrium
Unit 8⏱ 90 minGuided Inquiry
Overview
How can we use Le Chatelier’s Principle to explain phenomena of reversible reactions.
Objectives
- How can we use Le Chatelier’s Principle to explain phenomena of reversible reactions.
- Connect observations to AP Chemistry models and calculations.
⚠️ Wear protective goggles and an apron. Follow your teacher’s safety directions for all chemicals and equipment.
Materials Needed
Procedure
1
Clean four test tubes and label them 1, 2, 3 and 4.
2
Using a clean 10-mL graduated cylinder, pour 3.0 mL of 0.1 M CuSO4 to each of the test tubes.
3
Observe the color of the solutions.
4
Add 5 drops of ammonium hydroxide solution to test tube #2.
5
Shake the test tube.
6
Observe the reaction.
7
Note any changes.
8
Using a clean 10-mL graduated cylinder, add 3.0 mL of ammonium hydroxide solution to test tubes #3 and #4.
9
Shake the test tubes.
10
Compare this reaction to that of test tube #2.
11
To test tube #4, now add 10 drops of 1M sulfuric acid.
Pre-Lab Questions
1. In this experiment, would the same thing occur if we replaced sulfuric acid with hydrochloric acid? Explain why or why not. List the four stresses of Le Chatelier’s Principle and explain how each stress causes a shift in equilibrium. When would a change in pressure have no effect on an equilibrium reaction? Give two different situations where this would apply. In an exothermic reaction, what effect does increasing the temperature have on its equilibrium and why?