Name:_____________________________
Date:______________________________
Equilibrium Quiz
Mulitple Choice [ marks]
1. At a state of dynamic equilibrium,
what is the rate of the production of
reactants compared with the rate of
production of the products?
a. much higher
b. much lower
c. the same
d. very much lower
2. The equilibrium system shown below
was analyzed and the concentrations
of H2(g), I2(g) and HI(g), were found,
in mol/L, to be 4.2, 3.8, 1.6
respectively. The equilibrium
constant must be which of the
a. 0.10
following?
H2(g) + I2(g) <=====> 2HI(g) + 65 kJ
b. 28
c. 0.16
d. 2.3
e. 1.4
3. Which equilibrium constant
represents a reaction that is
essentially a forward reaction with a
large quantity of products present at
equilibrium?
a. 1 x 10-10
b. 2 x 100
c. 1 x 10-7
d. 2 x 1018
e. 3 x 10-18
4. Which change listed below would
shift the following reaction to the
right?
4
a. addition of Cl2
HCl (g) + O2 (g) <====> 2 Cl2 (g) + 2 H2O (g)
b. removal of O2
c. removal of H2O
d. removal of HCl
Short Answer [10 Marks]
Chemical Systems and Equilibrium
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SCH 4U
e. a and c
Name:_____________________________
Date:______________________________
5. For the equilibrium system below,
predict the direction the reaction
would shift – left/right; towards
products/reactants – when the
following changes are made to the
system. [4]
PCl3(g) + Cl2(g)  PCl5(g) + 45 kJ
Change
Shift
a) taking away Cl2
________________________________
b) increasing the pressure
________________________________
c) adding a catalyst
________________________________
d) increasing the temperature
________________________________
6. The following chemical reaction
equation represents the reaction
that takes place during the
manufacture of lime:
CaCO3 (s)
Limestone
CaO(s) + CO2 (g)
∆H = 178 kJ/mol
Lime
a) Modern manufacturers have replaced older stationary reaction chambers with rotating
reaction chamber that constantly feed in limestone and draw of lime. Use Le Chatelier’s
principle to explain why this would increase lime production. [2]
b) Would you expect the process to be run at high temperatures or low temperatures? Explain
[2]
Calculations [26 Marks]
Chemical Systems and Equilibrium
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SCH 4U
Name:_____________________________
Date:______________________________
7. For the reaction
H2(g) + Br2(g)
2 HBr
K = 12.0
(g)
Calculate the concentrations of all three substances at equilibrium using an ice table, if the
following amounts of reactants are mixed in a 2.00 – L reaction container – 8.0 mol of hydrogen
and 8.0 mol of bromine. [6]
8. The balanced chemical equation for
the synthesis of ammonia gas is
shown below,
N2 (g) + 3 H2(g)
2NH3 (g)
K = 6.01 x 10-2
For the conditions below determine if the system is at equilibrium. If the system is not at
equilibrium, in which direction will the equilibrium shift? [4]
[NH3(g)]initial: 1.00 x 10-4 mol/L
[N2(g)]initial:
5.00 mol/L
[H2(g)]intial: 1.00 x 10-2 mol/L
Chemical Systems and Equilibrium
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SCH 4U
Name:_____________________________
Date:______________________________
9. Balance the redox reaction listed
below if it occurs in a basic solution.
[5]
3+
Cr (aq) + Cl2 (g) → Cr2O7
2-
(aq) + Cl- (aq)
10. A chemist’s pure silver ring
accidently falls into a solution of
nitric acid, HNO3(aq). Predict
whether the acid will damage
(spontaneously) the gold ring. If the
reaction is spontaneously write a
balanced equation representing the
reaction [6]
Chemical Systems and Equilibrium
Page 4 of 4
SCH 4U