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Chemical Equilibrium STPM Term 1

Total questions: 15

Worksheet time: 28mins

Name
Class
Date
1.
Changes in pressure will only affect substances that are in the __________ state.
a)
gaseous
b)
liquid
c)
solid
d)
plasma
2.
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
3.

For the reaction...

SO2 + O2 ⇌ SO3

If the concentration of SO2 is increased, the equilibrium of the reaction will shift ___________.

a)

left

b)

right

c)

left and right

d)

neither left nor right

4.

For the reaction...

N2 (g) + 3 H2(g) ⇌ 2 NH3 (g)


If the pressure in the system is increased, which substance(s) will increase in concentration?

a)

N2

b)

H2

c)

N2 and H2

d)

NH3

5.

What is the effect of increasing the pressure on the following equilibrium: 2NO(g) + O2 (g) ⇌2NO2(g)?

a)

The yield of NO2 increases

b)

The yield of NO2 decreases

c)

The reaction is slower

d)

The concentration of O2 increases.

6.

H2(g)+Cl2(g)⇌2HCl(g)

Removing Cl2(g) will

a)

shift equilibrium right

b)

shift equilibrium left

c)

increase pressure

d)

have no change

7.

H2(g)+Cl2(g)⇌2HCl(g)

The forward reaction is exothermic. What will happen to the equilibrium if the temperature is increased?

a)

equilibrium shifts right

b)

equilibrium shifts left

c)

You cannot predict the effect

d)

no change

8.
At what time the reaction reached equilibrium?
a)
t1
b)
t2
c)
t3
d)
t4
9.
How do catalysts increase the rate of reaction?
a)
The frequency of collisions is the increased
b)
the activation energy is lowered
c)
the energy of collisions is increased
d)
Both the frequency and energy of collisions is increased
10.

For the following reaction: H2(g) + Cl2 (g) ↔ 2HCl(g), calculate the concentration of HCl when Keq= 2.3x10-5, [H2]= 0.0056mol, [Cl2]= 0.0048mol.

a)

6.2 x 10-10 M

b)

2.5 x 10-5 M

c)

1.1 M

d)

1.2 M

11.

For the following reaction: H2(g) + Cl2 (g) ↔ 2HCl(g), calculate the concentration of HCl when Keq= 2.3x10-5, [H2]= 0.0056mol, [Cl2]= 0.0048mol.

a)

6.2 x 10-10 M

b)

2.5 x 10-5 M

c)

1.1 M

d)

1.2 M

12.

When pressure decreases, in which direction does the equilibrium shift?

a)

The equilibrium shifts in the direction that increases the number of moles of gas.

b)

The equilibrium shifts in the direction that decreases the number of moles of gas.

c)

The equilibrium does not shift.

d)

The equilibrium shifts always shifts to the right.

e)

The equilibrium shifts always shifts to the left.

13.

Consider this system:

2CCl4(g) + O2(g)<->2COCl2(g) + 2Cl2(g) ΔH = -35 kJ/molrxn

Predict the effect of increasing temperature.

a)

Speed up forward reaction.

b)

Speed up reverse reaction.

c)

No change.

14.
A system at equilibrium means it is still reacting.
a)
True
b)
False
15.
The picture shows a reversible chemical reaction taking place. How can equilibrium be reached?
a)
Stopper the flask.
b)
Add more reactants.
c)
Add more products.
d)
Cool the contents.