A STUDY OF EQULIBRIUM
EVALUATION
The following assignment will be your evaluation for the lab: A Study of Equilibrium.
You will not be required to hand in a separate lab write up.
The lab process therefore will be the following:
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You are required to work through the lab during your lab section.
You will use the information you collect during the lab to complete the following assignment.
The assignment will be due at the end of class.
The lab will be graded on a negative basis. Unless otherwise specified, one mark will be
deducted for each error or omission. Your response must be logical and clear. You may use
equations, diagrams, or point form in your responses.
EQUILIBRIUM LAB ASSIGNMENT
NAME: ________________________________________________________________________
The following questions are general questions related to the laboratory.
1.
What is required for dynamic equilibrium. (1 mark)
2.
State LeChatelier’s Principle. (1 mark)
3.
Describe simultaneous equilibria. (1 mark)
4.
If hydrochloric acid was added to an acidic equilibrium system, what effect did it have upon the
hydrogen ion concentration? (1 mark)
5.
If sodium hydroxide was added to an acidic equilibrium system, what effect did it have upon the
hydrogen ion concentration? Explain. (2 marks)
The questions on this portion of the assignment correspond to the laboratory procedure. For example,
the first set of questions below, correspond to Procedure I, Indicator Equilibria in the lab handout.
I.
Indicator Equilibrium
6.
What is an indicator and how is it used? (1 mark)
7.
Use the equation for the equilibrium to show what happens when HCl (aq) is added to the
system. (1 mark)
8.
If the equilibrium system indicated in this procedure is yellow, what change would need to be
imposed to shift the equilibrium to blue? Explain. (2 marks)
II.
Chromate-Dichromate Equilibrium
9. Use the equation for the equilibrium to show what happens when sodium hydroxide is added to
the equilibrium. In your response include the color change, if applicable. (2 marks)
10. If the equilibrium is yellow, what change would need to be imposed to shift the equilibrium to
orange? Explain. (2 marks)
III.
Solubility Equilibrium and Simultaneous Equilibria
11. What is the common substance in this equilibrium system? (1 mark)
12. Which substance is indicated by the presence of a white precipitate? (1 mark)
13. Use the equilibrium equations to explain the change that occurs when NaOH (aq) is added to
the system. ( 2 marks)
14. If a white precipitate is not present in this simultaneous equilibrium system, what change would
you need to impose to remove the precipitate? Explain. (2 marks)
IV.
Equilibrium in Ammonia Solution
15. Part A of this procedure involved proving the presence of all the components of the equilibrium
system.
a. What indicated the presence of the hydroxide ion? (1 mark)
b.
What indicated the presence of the ammonia? (1 mark)
16. In Part B of this procedure, you are testing for the presence of ammonia and the presence of
the hydroxide ion. One is a reactant and one is a product. What is the relevance of testing for
the presence of a reactant and a product? (1 mark)
17. In Part C of this procedure.
a. What change is noted when you sequentially add copper (II) nitrate, ammonia, and
hydrochloric acid? ( 1 mark)
b.
What does this demonstrate? (1 mark)