Free Printable U3 Equilibrium

1.

An important industrial process is the conversion of carbon monoxide into carbon dioxide using steam.

CO(g) + H₂O(g) ↔ CO₂(g) + H₂(g); ΔH = -40 kJ mol^-1

Which of the following would increase the conversion of CO into CO₂?

a)

Increasing the pressure

b)

Increasing the temperature

c)

Increasing the concentration of water

d)

Increasing the volume of the container

2.

In the commercial production of methanol, CH₃OH, carbon monoxide and hydrogen are heated and passed over a catalyst. The following equilibrium is set up.

CO(g) + 2H₂(g) ↔ CH₃OH(g) ; ΔH = -95 kJ mol^-1

The reaction does not go to completion and the conditions have to be carefully adjusted to produce a maximum yield.

Which of the following would be expected to increase the yield of methanol?

a)

Condense the methanol and recycle the remaining gases

b)

Lower the pressure in the reaction vessel

c)

Use a more effective catalyst

d)

Increase the temperature in the reaction vessel

3.

When hydrogen (H₂) and iodine (I₂) react, hydrogen iodide (HI) is formed.

H₂ (g) + I₂ (g) ↔ 2HI (g)

In one experiment in a 2.0L vessel at a certain temperature, the equilibrium mixture contained 0.5 mol of HI, 0.25 mol of H₂ and 0.2 mol of I₂.

The value for the equilibrium constant at this temperature is:

a)

0.05

b)

0.1

c)

10

d)

20

4.

In the production of nitric acid, an important step is the conversion of nitric oxide (NO) into nitrogen dioxide (NO₂).

2NO (g) + O₂(g) ↔ 2NO₂ (g); ΔkJ mol^-1

Which of the following sets of conditions would be expected to give the best equilibrium yield of nitrogen dioxide?

a)

500°C and 4 atm pressure

b)

30°C and 4 atm pressure

c)

500°C and 1 atm pressure

d)

30°C and 1 atm pressure

5.

Oxygen reacts with haemoglobin(Hb₄) in the lungs to form a complex(Hb₄(O₂)₄). This complex is moved around the body to take oxygen to the tissues. The reaction is represented by the equilibrium shown below.

Hb₄ + 4O₂ ↔ Hb₄(O₂)₄

When equilibrium is established in the lungs, the equilibrium constant, Keq can be represented as:

a)

b)

c)

d)

6.

$Hb_4+4O_2\ ↔Hb_4(O_2)_4$
Even at low concentration carbon monoxide is poisonous. It reacts with haemoglobin(Hb₄)and thus prevents oxygen from being carried around the body. The body is deprived of oxygen. The equation that best represents this poisoning is:

a)

4 $CO(g)+Hb_4(O_2)_4\ \leftrightarrow\ Hb_4(CO)_4+4O_2(g)$

b)

$12CO(g)+Hb_4(O_2)_4\ ↔\ Hb_4(CO)_4+8CO_2(g)$

c)

$4CO(g)+Hb_4(O_2)_4\ ↔\ Hb_4(CO_2)_4+2O_2(g)$

d)

$4CO(g)+Hb_4(O_2)_4\ ↔\ Hb_4(CO_2)_4+2O_2(g)$ $4CO(g)+4H_2O(l)+Hb4\ \ ↔\ Hb_4(HCOOH)_4$

e)

Hb4

7.

Find the equilibrium expression for this reaction.

Fe(OH)₃(aq) ↔ Fe³⁺(aq) + 3OH^-(aq)

a)

b)

c)

d)

8.

HNO₂(aq) ↔ H⁺(aq) + NO₂^-(aq)

The aqueous equilibrium reaction above would NOT be affect by

a)

the addition of NaNO₃(s)

b)

an increase in H⁺concentration

c)

the addition of NaNO₂(s)

d)

a decrease in the HNO₂ concentration

9.

CrO₄^2-(aq) are yellow.

Cr₂O₇^2-(aq) are orange.

If acid is added to neutralise hydroxide ions in the following equilibrium system, what will be the colour change?

H₂O(l) + 2CrO₄^2-(aq) ↔ Cr₂O₇^2-(aq) + 2OH^-(aq)

a)

no change

b)

lighter orange

c)

darker orange

d)

darker yellow

10.

The graph shows changes in concentration over time at 350°C for the following reaction.

H₂(g) + I₂(g) ↔ 2HI(g).

Interpet the changes in the three curves between t=0 min and t=10 min.

4 lines

U3 Equilibrium

Total questions: 10

Worksheet time: 5mins

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