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Introduction to Equilibrium

Total questions: 85

Worksheet time: 2hrs 51mins

Name
Class
Date
1.
Le Chaltelier's Principle states that if a chemical system at equilibrium is stressed,
a)
the system will adjust to increase the stress
b)
the system will adjust to reduce the stress
c)
the system will not adjust
2.
Which of the following is not a way to stress a chemical system?
a)
temperature
b)
pressure
c)
time
3.
A reaction that releases heat energy is known as
a)
endothermic
b)
exothermic
c)
isothermic
4.
When writing an endothermic reaction, heat energy is stated as
a)
product
b)
catalyst
c)
reactant
5.
An exothermic reaction is allowed to reach equilibrium. If heat energy is then removed, the equilibrium will shift
a)
toward the middle
b)
toward the reactant side
c)
toward the product side
6.
Changes in pressure will only affect substances that are in the __________ state.
a)
gaseous
b)
liquid
c)
solid
7.
An increase of concentration in a system at chemical equilibrium will cause the reaction to shift
a)
to the same side
b)
to the opposite side
c)
no shift will occur
8.
For the reaction...
heat  +  N2  +  O2  <−>  2NO
If  O2 is removed, the  concentration of N2 will _______.
a)
increase
b)
decrease
c)
remain the same
d)
double
9.
For the reaction...
heat  +  N2  +  O2  <−>  2NO
If  NO is removed  from the system, the concentration of N2 will _______.
a)
increase
b)
decrease
c)
remain the same
d)
double
10.
For the reaction...
heat  +  N2  +  O2  <−>  2NO
If the heat is added to the chemical system, the equilibrium will shift _______.
a)
left
b)
right
c)
left and right
d)
neither left nor right
11.
For the reaction...
heat  +  N2  +  O2  <−>  2NO
If the heat is removed to the chemical system, the equilibrium will shift _______.
a)
left
b)
right
c)
both left and right
d)
neither left nor right
12.
For the reaction...
H2 (g)  + Cl2 (g) <−>  2HCl (g)  +  heat
If the pressure in the system is increased, the equilibrium will _______.
a)
shift left
b)
shift right
c)
not shift
13.
For the reaction...
N2 (g) +  3 H2 (g) <−> 2 NH3 (g)

If the pressure in the system is increased,  _______ reaction will be favored.
a)
 the forward
b)
the reverse
c)
neither
14.
Changes in pressure will only affect substances that are in the __________ state.
a)
gaseous
b)
liquid
c)
solid
d)
plasma
15.

Consider the following reaction. What would be the equilibrium constant expression?

4Br2(g) + CH4(g) ↔ 4HBr(g) + CBr4(g)

a)

[Br2]4 [CH4]/ [HBr]4 [CBr4]

b)

[HBr]4 [CBr4]/ [Br2]4 [CH4]

c)

[HBr ]/ [Br2]4 [CH4]

d)

[HBr]4 [CBr4]/ [Br2]4 [CH4]4

16.

Such reactions which continue in both directions are called:

a)

Irreversible reactions

b)

Reversible reactions

c)

Non-reactive reactions

d)

dynamic reactions

17.
2SO2(g)+O2(g)⇌2SO3(g)
Decreasing volume of container will
a)
shift equilibrium right
b)
shift equilibrium left
c)
change K
d)
have no change
18.
What causes the reaction to go REVERSE
A  + B ↔ C + D + energy
a)
Decreasing D
b)
Increasing C
c)
Decreasing A
d)
Decreasing Temperature
19.
What causes the reaction to go FORWARD
A  + B ↔ C + D + energy
a)
Increasing D
b)
Increasing C
c)
Increasing B
d)
Increasing Temperature
20.
Define chemical equilibrium.
a)
A reaction is reversible.
b)
The concentration of the reactants is equal to the concentration of the products.
c)
The rate of a forward reaction is equal to the rate of the reverse reaction.
d)
The reaction stops and no further change in concentration occurs.
21.

A complete reaction is in which:

a)

All the reactants convert into products

b)

All the reactants do not convert into products

c)

Half reactants convert into products

d)

only 10% reactants convert into products

22.
2SO2(g)+O2(g)⇌2SO3(g)
Removing O2(g) will
a)
shift equilibrium right
b)
shift equilibrium left
c)
decrease temperature
d)
have no change
23.
2SO2(g)+O2(g)⇌2SO3(g)
Adding SO2(g) will
a)
shift equilibrium right
b)
shift equilibrium left
c)
increase rate of reaction
d)
have no change
24.

At elevated temperatures ammonium carbonate, NH2COONH4, is in equilibrium with NH3 and CO2 according to the equation;

NH2COONH4(s) ↔ 2 NH3(g) + CO2(g)

What is the equilibrium expression for this reaction?

a)

K = 2 [NH3][CO2]

[NH2COONH4]

b)

K = [NH3]2[CO2]

[NH2COONH4]

c)

K = 2 [NH3][CO2]

d)

K = [NH3]2[CO2]

25.
What is the equilibrium-constant expression for 
CO2(g) + H2(g) ↔ CO(g) + H2O(l)
a)
Kc= [CO][H2O] / [CO2][H2]  
b)
Kc= [CO2][H2] / [CO]
c)
Kc= [CO2][H2] / [CO][H2O]
d)
Kc= [CO] / [CO2][H2]  
26.
This symbol indicates that a reaction is ____________
a)
reversible
b)
irreversible
27.
2SO2(g)+O2(g)⇌2SO3(g)
Decreasing volume of container will
a)
shift equilibrium right
b)
shift equilibrium left
c)
change K
d)
have no change
28.
For the reaction...
heat  +  N2  +  O2  ↔  2NO
If the heat is added to the chemical system, the equilibrium will shift _______.
a)
left
b)
right
c)
left and right
d)
neither left nor right
29.
What are the two factors to look for when determining if the reaction is at equilibrium?
a)
Forward reaction rate is faster than the reverse and concentrations are equal
b)
Forward and reverse reaction rates are equal and concentration is constant
c)
Forward and revers reaction rates are equal and concentration is equal
d)
Forward reaction rate is faster than the reverse and concentration is equal
30.
When the rate of the forward reaction is equal to the rate of backward reaction, the system is said to be in
a)
Chemical Equilibrium
b)
Chemical Balance
c)
Stoichiometry
d)
Chemical Reaction
31.
Identify the labels (a) and (b) on the graph.
a)
a is concentration of reactants and b is the concentration of products
b)
a is concentration of product and b is the concentration of reactant
c)
a is the volume of reactants and b is the volume of product
d)
a is the mass of reactants and b is the mass of product
32.
Which of the following is NOT true at equilibrium?
a)
The forward and reverse reactions proceed at the same rate.
b)
The concentrations of reactants and products do not change.
c)
The concentration of the reactants is equal to the concentration of the products.
d)
The forward and reverse reactions continue to occur.
33.
The idea that when a system at equilibrium is stressed, it will react to relieve that stress and return to equilibrium is known as:
a)
Boyle's Law
b)
Le Chatelier's Principle
c)
Charles Law
d)
Switzer's Law
34.
2SO2(g)+O2(g)⇌2SO3(g)
Removing O2(g) will
a)
shift equilibrium right
b)
shift equilibrium left
c)
increase pressure
d)
have no change
35.
2SO2(g)+O2(g)⇌2SO3(g)
Adding O2(g) will
a)
shift equilibrium right
b)
shift equilibrium left
c)
decrease pressure
d)
have no change
36.
2SO2(g)+O2(g)⇌2SO3(g)
Adding SO3(g) will
a)
shift equilibrium right
b)
shift equilibrium left
c)
increase K
d)
have no change
37.
CH4 + 2 O2 ↔ CO2 + 2 H2O + 30 kJ
If CHwas removed, what happens to the [O2]
a)
Increase
b)
Decrease
c)
Left
d)
Right
38.
What causes the reaction to go REVERSE
A  + B ↔ C + D + energy
a)
Decreasing D
b)
Increasing C
c)
Decreasing A
d)
Decreasing Temperature
39.
What causes the reaction to go FORWARD
A  + B ↔ C + D + energy
a)
Increasing D
b)
Increasing C
c)
Increasing B
d)
Increasing Temperature
40.
Define chemical equilibrium.
a)
A reaction is reversible.
b)
The concentration of the reactants is equal to the concentration of the products.
c)
The rate of a forward reaction is equal to the rate of the reverse reaction.
d)
The reaction stops and no further change in concentration occurs.
41.
For the reaction...
H2 (g)  + Cl2 (g) <−>  2HCl (g)  +  heat
If the pressure in the system is increased, the equilibrium will _______.
a)
shift left
b)
shift right
c)
not shift
42.
An exothermic reaction is allowed to reach equilibrium. If heat energy is then removed, the equilibrium will shift
a)
toward the middle
b)
toward the reactant side
c)
toward the product side
43.
In an exothermic reaction, heat is ...
a)
taken in
b)
given out
44.
In an endothermic reaction, heat is 
a)
taken in
b)
given out
45.
Activation energy is required to start a chemical reaction. What is activation energy?
a)
The energy needed for a reaction to occur
b)
The minimum amount of energy needed for a reaction to potentially occur
c)
The energy added by a catalyst
d)
The energy possessed by the products
46.
For the reaction...
SO2 + O2 ↔ SO3
If the equilibrium shifts to the right, the concentration of SO3 will ___________.
a)
increase
b)
decrease
c)
remain the same
d)
double
47.
For the reaction...
heat  +  N2  +  O2  ↔  2NO
If the heat is added to the chemical system, the equilibrium will shift _______.
a)
left
b)
right
c)
left and right
d)
neither left nor right
48.
For the reaction...
N2 (g) +  3 H2 (g) ↔ 2 NH3 (g)

If the pressure in the system is increased,  _______ reaction will be favored.
a)
 the forward
b)
the reverse
c)
neither
49.
When K is large, 
a)
There are more products than reactants when the reaction reached equilibrium.
b)
There are more reactant than products when the reaction reached equilibrium.
c)
The amount of reactants is equal to the amount of products.
50.
What is the proper K for the following reaction? 
   2 NO(g)  +  O2(g)  2 NO2(g)
a)
K = [NO2]2 / [NO]2[O2]
b)
K =  [NO]2[O2] / [NO2]2
c)
K = [NO]2[O2][NO2]2
d)
K = 2[NO][O2] / 2[NO2]
51.
What is n and m?
a)
Coefficient of Products in the Balanced Reaction
b)
Coefficient of Reactants in the Balanced Reaction
c)
Order of Reaction with respect to the products
d)
Order of Reaction with respect to the Reactants
52.
True or False: The value of Keq is constant at ANY temperature.
a)
True
b)
False, it is only constant at a SPECIFIC temperature
53.
Keq < 1
a)
There are more products than reactants when the reaction reached equilibrium.
b)
There are more reactant than products when the reaction reached equilibrium.
c)
The amount of reactants is equal to the amount of products.
54.
What is equilibrium?
a)
Reaction stops once products are formed.
b)
Reactants and products are being formed constantly.
c)
Reaction uses up all of the reactants.
55.
T/F: At equilibrium, the amount of reactants and products are the same.
a)
True
b)
False
56.
T/F: At equilibrium, the rate of transfer between the reactants and products is unequal.
a)
True
b)
False
57.
T/F: At equilibrium, the rate of transfer between the reactants and products is equal.
a)
True
b)
False
58.
T/F: A reaction must start with the same amount of reactants as products to reach equilibrium.
a)
True
b)
False
59.
CH4 is added. The reaction will shift:
a)
Right
b)
Left
c)
No Shift
60.
H2O is removed. The reaction will shift:
a)
Right
b)
Left
c)
No Shift
61.
The reaction is cooled. The reaction will shift:
a)
Right
b)
Left
c)
No Shift
62.
Ne (neon) is added. The reaction will shift:
a)
Right
b)
Left
c)
No Shift
63.
What time is equilibrium reached?
a)
0 s
b)
2000 s
c)
6000 s
64.
What are the two types of stresses that can shift equilibrium?
a)
Concentration and Catalyst
b)
Concentration and Temperature
c)
Catalyst and Temperature
65.

Consider the reaction:

4NH3 (aq) + 7O2 (G) => 4NO2 (g) + 6H20 (L)

the equilibrium constant,Kc for the reaction should be written as?

a)

[NO2}4

[NH3]4[O2]7

b)

[NO2][H2O]

c)

[NO2]4[H2O]6

d)

[NO2]4[H2O]7

66.

Which of the following equilibrium equation would be shifted toward the right when the pressure is raised at constant temperature

a)

PCl5 => PCl3 + Cl2

b)

O2 + 4F2 => F4 + 2F2O

c)

NH4HS => NH3 + H2S

d)

3Fe + 4H2O=> F3O4 + 4h2

67.

An equilibrium is represented by the following equation:

2SO2 + O2 = 2SO3 H=-yKj mol-1


Which of the following changes would effect the value of equilibrium constant,Kp and the proportion of sulfur trioxide present at equilibrium?

a)

Reducing the temperature

b)

Adding the catalyst

c)

Increasing the pressure

d)

Increasing the mass of oxygen

68.

Which statement describe a system at equilibrium?

a)

Kforward = Kreverse

b)

Amount of reactant and product are equal

c)

When the reactant used up,the reaction stop.

d)

The rate of forward reaction equal the rate of reverse reaction

69.
What are [A] and [B]?
a)
concentration of reactants
b)
concentration of products
c)
energy of reactants
d)
energy of products
70.
For the reaction...
H2 (g)  + Cl2 (g) <=>  2HCl (g)  +  heat
If the pressure in the system is increased, the equilibrium position will _______.
a)
shift to the left
b)
shift to the right
c)
not shift position at all as 2 mol gas <=> 2 mol gas
71.

2 SO2(g) + O2(g)↔️ 2SO3(g) +198kJ

Which side would the equilibrium shift if the temperature is increased?

a)

To the right

b)

To the left

c)

Stays the same

72.

2 SO2(g) + O2(g)↔️ 2SO3(g) +198kJ

Which side would the equilibrium shift if the temperature is decreased?

a)

To the left

b)

To the right

c)

Stays the same

73.

2 SO2(g) + O2(g)↔️ 2SO3(g) +198kJ

Which side would the equilibrium shift if the pressure is increased?

a)

To the right

b)

To the left

c)

Stays the same

d)

It can shift both sides

74.

2 SO2(g) + O2(g)↔️ 2SO3(g) +198kJ


Which side would the equilibrium shift if SO2 is added?

a)

To the right

b)

To the left

c)

Stays the same

d)

It can shift both sides

75.

2 SO2(g) + O2(g)↔️ 2SO3(g) +198kJ


Which side would the equilibrium shift if SO2 is added?

a)

To the right

b)

To the left

c)

Stays the same

d)

It can shift both sides

76.

2 SO2(g) + O2(g)↔️ 2SO3(g) +198kJ

Which side would the equilibrium shift if SO2 is removed?

a)

To the right

b)

To the left

c)

Stays the same

d)

It can shift both sides

77.

SO2(g) + O2(g)↔️ 2SO3(g) +198kJ

How would the equilibrium shift if SO3 is removed?

a)

To the left

b)

To the right

c)

Stays the same

d)

It can shift both sides

78.

2 SO2(g) + O2(g)↔️ 2SO3(g) +198kJ

What kind of reaction is this?

a)

Endothermic

b)

Exothermic

c)

Ecothemic

d)

None of the above

79.

How do you know when a reaction has reached equilibrium?

a)

When the particles are the same on both sides

b)

When the reaction is endothermic

c)

When a reaction is exothermic

d)

When the concentration of the reactants and products no longer changes- the rate of forward reaction is equal to the rate of reverse reaction.

80.

Which of these does not affect equilibrium?

a)

Concentration

b)

Temperature

c)

Catalyst

d)

Pressure

81.

Which side would an exothermic reaction favor if there is an increase in temperature.

a)

Both the reactants and the products

b)

Reactants

c)

Products

82.

Which side would an endothermic reaction favor if there is an increase in temperature.

a)

Both the reactants and the products

b)

Reactants

c)

Products

83.

Which side would an exothermic reaction favor if there is an decrease in temperature.

a)

Both the reactants and the products

b)

Reactants

c)

Products

84.

Which side would an endothermic reaction favor if there is an decrease in temperature.

a)

Both the reactants and the products

b)

Reactants

c)

Products

85.

Increasing pressure....

a)

Decreases volume and favors the side with more moles

b)

Increases volume and favors the side with more moles

c)

Decreases volume and favors the side with fewer moles

d)

Increases volume and favors the side with fewer moles