Equilibrium MINI Assessment
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Name: _____________________________
Complete by hand and email pictures to reidla@limestone.on.ca by June 15 at the latest. (Final marks are due a few
days later. This deadline must be observed to be included in the final grade.)
PART A: Multiple Choice
Identify the choice that best completes the statement or answers the question.
____
a.
b.
c.
d.
2.
Consider two reactants, A and B, that produce products C and D. Suppose the equilibrium constant is
very large. What does this indicate?
The production of products is favoured.
The reaction will not proceed.
The production of reactants and products is equal.
The production of reactants is favoured.
____
a.
b.
c.
d.
If the equilibrium constant, K, for a reaction is 2.5, which is the value of the equilibrium constant for the
reverse reaction?
2.5
6.25
1.0
0.4
____
a.
b.
c.
d.
1.
3.
106
10–6
10–1
10–1
3.4
2.9
9.8
1.5
____
Which of the following equilibrium constant values best represents a reaction where the concentration
of products is almost equal to the concentration of reactants?
4.
Which is the correct equilibrium law expression for the following reaction?
6 C (s) + 3 H2 (g)  C6H6 (l)
a. K =__ [C6H6 (l)]____
[C(s)]6[H2(g)]3
b. K =___1_____
[H2(g)]3
c. K =__ [C6H6 (l)]____
[C(s)][H2(g)]
d. K =__[C(s)]6[H2(g)]3
[C6H6 (l)]
PART B: True/False
Indicate whether the statement is true or false.
_______
5.
Equilibrium can only occur in a closed system.
_______
6.
The concentrations of solids are included in the equilibrium law equation when dealing with a
chemical equilibrium system.
_______
7.
Equilibrium reactions do not go to completion.
_______
8.
Heterogeneous equilibria have products and reactants in the same phase.
_______
9.
Chemical equilibrium means that all chemical reactions have stopped.
_______
10.
At equilibrium the concentration of the reactants is always equal to the concentration of the
products.
PART C: Short Answer
11.
Carbon monoxide gas reacts with hydrogen gas to form methanol gas.
a)
Write the equilibrium law expression.
[2 marks]
b)
Calculate the value of the equilibrium constant at 327 °C if an equilibrium mixture in a 2.0 L vessel
contains 1.60 mol of carbon monoxide gas, 2.50 mol hydrogen gas, and 0.500 mol of methanol gas.
[3 marks]
c)
Is the equilibrium formed reactant favoured or product favoured? How do you know? [1 mark]
12.
Write the equilibrium law expression for the reaction of solid aluminum with iron (II) chloride solution. [3 marks]
13.
Ammonia is formed according to the reaction:
N2 (g) + 3 H2 (g)  2 NH3 (g)
Nitrogen and hydrogen are introduced into a closed vessel. The initial concentration of nitrogen is
1.5 mol/L and the initial concentration of hydrogen is 5.0 mol/L. The concentration of nitrogen at
equilibrium is measured to be 0.005 mol/L. Calculate the equilibrium concentrations of hydrogen and
ammonia.
[5 marks]
14.
Write a balanced chemical equation for the following equilibrium law expression:
K=
[SO3 (g)]2____
[SO2 (g)]2[O2 (g)]
[2 marks]