Equilibrium and Le Chatelier’s Principle

Table 1

Quantity of Reagents    Quantity of Reagents    Quantity of Reagents    Quantity of Reagents    Quantity of Reagents

Reagent Test Tube #1, Control Test Tube #2 Test Tube #3 Test Tube #4 Test Tube #5
Copper (II) Chloride 2.0 mL 2.0 mL 2.0 mL 2.0 mL 2.0 mL
Sodium Chloride 0.0 mL
1.0 mL

2.0 mL

4.0 mL

4.0 mL

Color of Solution
Silver Nitrate N/A N/A 1.0 mL N/A N/A
Color of Solution N/A N/A N/A N/A
Water N/A N/A N/A 3.0 mL N/A
Color of Solution N/A N/A N/A N/A

 
Activity 4

Table 2

Stress Water Bath Temperature (°C) Solution Temperature
(°C) Solution Color Direction of Shift
(reactants or products) ( or )
Test tube #4
(Control Solution)
Hot Water Bath
Cold Water Bath

Photos

Place the tubes on a white paper with adequate light. Use of white paper as a background will assist with view and color comparisons. Color changes may be subtle. Labels and colors of the liquid must be visible

Photo 1
Insert the photo of test tubes #1-5 from Activity 1. Compare the colors of the solutions in test tubes #2–5 to that in test tube #1.

Photo 2
Insert the photo of test tubes #1 and #3 from Activity 2.

Photo 3
Insert the photo of test tubes #4 and #5 from Activity 3.

Photo 4
Insert the photo of test tubes #4 and #5 from Activity 4, step 8.

Photo 5
Insert the photo of test tubes #4 and #5 from Activity 4, step 13.

Lab Questions

1. What is the “common ion” that you added to test tubes #2–5, and how it affect the equilibrium reaction?
2. Write an equation showing what happens when AgNO3 is added, and explain why the equilibrium shifts. Provide the experimental observation.
3. Explain the equilibrium shift that occurs when water is added to the original equilibrium reaction. Provide the experimental observation.
4. Write “heat” on either the left or right side of this equation, based upon Activity 4.
   _ + Cu(H2O)62+(aq) + 4Cl–(aq)  CuCl42–(aq) + 6H2O(l) + _

Blue
Green

5. Consider the chemical reaction: N2 + 3H2 yields 2NH3. The equilibrium constant is K = 6.0 x 10-2, and concentrations are as follows [H2] = 2.5 x 10-1 M, [N2] = 4.0 M, and [NH3] = 1.0 x 10-4 M. Is the reaction at equilibrium? If not, which direction would it shift? Show your calculations.
6. Given this reaction at equilibrium, C(s) + CO2(g)  2CO(g) (∆H° = 119kJ), explain the changes that would occur when the following stresses are applied:
   (a) CO is removed.

(b) Heat is removed.

(c) CO2 is added.

7. Describe sources of error in this experiment.

Conclusions

Sample Solution