NAME :
DAY, DATE :
1
In which of these equilibria is
the forward reaction favoured by an increase in pressure?
A 2HI(g) <=> H2(g) + I2(g)
B N2O4(g) <=> 2NO2(g)
C 2NO(g) + O2(g) <=> 2NO2(g)
D PCl 5(g) <=> PCl 3(g) + Cl 2(g)
2
Methanol is made in
industry by a reaction between carbon monoxide and hydrogen.
CO(g) + 2H2(g) <=> CH3OH(g) ∆H = –90 kJ / mol
The process is
usually carried out at a temperature of 400 °C.
Which row correctly shows the effect on both the position of the
equilibrium and on the rate of the reaction of increasing the temperature to
above 400 °C?
|
|
position of equilibrium |
rate of reaction |
|
A B C D |
moves to left moves to
left moves to right moves to right |
decreases increases decreases increases |
3
Chlorine can be manufactured by
the following reaction.
4HCl
(g) + O2(g) <=> 2H2O(g) + 2Cl 2(g) ∆H is negative A mixture in
dynamic equilibrium is formed.
Which change to
the mixture will increase the amount of chlorine at equilibrium?
A
adding a catalyst
B
adding more HCl (g)
C
decreasing the pressure
D
increasing the temperature
4
When bismuth(III) chloride, BiCl 3, is added
to water, a white precipitate of BiOCl is formed.
BiCl 3(aq) + H2O(l) <=> BiOCl (s) + 2HCl (aq)
If this
reversible reaction is at equilibrium and hydrochloric acid is added, what will
happen?
A The position of equilibrium moves to the left and more white precipitate is formed.
B The position of equilibrium moves to the left and the white precipitate disappears.
C The position of equilibrium moves to the right and more white precipitate is formed.
D The position of
equilibrium moves to the right and the white precipitate disappears.
5
The following reversible
reaction takes place in a closed vessel at constant temperature.
P(g) + Q(g) + R(g) <=> S(g) +
T(g)
When the system has reached equilibrium, more T is added. Which
increases in concentration occur?
A
P, Q, R and S
B P and Q only
C P, Q and R only
D S only
6
When a solution containing
silver ions is added to a solution containing iron(II) ions, an equilibrium is
set up.
Ag+(aq) + Fe2+(aq) <=> Ag(s) +
Fe3+(aq)
The addition
of which substance would not affect the amount of silver precipitated?
A Ag+(aq) B Fe2+(aq) C Fe3+(aq) D H2O(l)
7
The equation shows the
formation of sulfur trioxide in the Contact
process.
2SO2(g) + O2(g) <=> 2SO3(g) ∆H = –95 kJ / mol
What would decrease
the yield of sulfur trioxide in a given time?
A addition of more oxygen
B an increase in pressure
C an increase in temperature
D removal of SO3(g) from the
reaction chamber
8
The equation shows a reversible reaction.
N2O4(g) <=> 2NO2(g)
The forward
reaction is endothermic.
Which of
these changes will increase the yield of NO2?
9
In the Contact process for
making sulfuric acid, one step involves the oxidation of sulfur dioxide to
sulfur trioxide.
2SO2(g) + O2(g) <=> 2SO3(g)
The forward
reaction is exothermic.
Which change
would increase the amount of sulfur trioxide produced at equilibrium?
A adding a catalyst
B decreasing the pressure
C decreasing the temparature
D increasing the temperature
10
At 400 °C the reaction between
hydrogen and iodine reaches an equilibrium.
H2(g) + I2(g) <=> 2HI(g) ∆H = –13 kJ
Which change in
conditions would increase the percentage of hydrogen iodide in the equilibrium
mixture?
A
a decrease in pressure
B
a decrease in temperature
C
an increase in pressure
D
an increase in temperature
11 In the Haber process, nitrogen and hydrogen react to form ammonia.
N2(g) + 3H2(g) 2NH3(g) ∆H = –92 kJ
Which factor
increases both the speed of reaction and the amount of ammonia produced?
A addition of a catalyst
B decreasing the temperature
C increasing the pressure
D increasing the temperature
12
The equation shows the reaction
for the formation of sulphur trioxide.
2SO2(g) + O2(g) <=> 2SO3(g) ∆H = –197 kJ
Which change
in reaction conditions would produce more sulphur trioxide?
A adding more catalyst
B decreasing the pressure
C increasing the temperature
D
removing some sulphur trioxide
13
The reversible reaction below
has reached dynamic equilibrium.
N2O4(g) <=> 2NO2(g)
What does the
term dynamic equilibrium mean?
A The reaction has stopped.
B The rate of the forward reaction is now zero.
C The concentrations of NO2 and N2O4 are equal.
D The rates of the forward and backward reactions are equal.
14
Ammonia is made by a reversible
reaction between nitrogen and hydrogen.
The equation for
the reaction is shown.
N2(g) + 3H2(g) <=> 2NH3(g) ∆H is negative What is the
effect of increasing the pressure in this process?
A
Less ammonia is formed.
B Less heat is produced.
C More ammonia is formed.
D The reaction slows down.
15 Nitrogen reacts with oxygen.
N2(g) + O2(g) <=> 2NO(g) ∆H = +170 kJ / mol
At equilibrium,
which statement is true?
A The concentration of nitrogen present will change with time.
B The forward and backward reaction are taking place at the same rate.
C The forward reaction releases heat
energy.
D There are more molecules on the left hand side of the equation than
on the right.
16
In the Haber process, nitrogen
and hydrogen react to form ammonia.
What is the source of the hydrogen?
A
A. air
B
B. oil
C
C. limestone
D
D. sulphuric acid
17 Nitrogen dioxide, NO2, is a dark brown gas that decomposes as shown by the equilibrium equation.
2NO2(g) <=> 2NO(g) + O2(g)
dark brown colourless
The diagram shows a glass flask containing a mixture of the three
gases. The mixture is pale brown.
More oxygen is
forced into the flask.
What colour
change is seen in the mixture?
A
there is no change
B
it turns colourless
C
it becomes darker brown
D
it becomes a paler brown
18
The diagram shows processes
that take place in the manufacture of ammonia.
What are
substances W and X and catalyst Y?
|
|
W |
X |
Y |
|
A B C D |
air air oil oil |
oil oil air air |
iron vanadium(V) oxide iron vanadium(V) oxide |
19
Which statement about the
manufacture of ammonia by the Haber Process is
correct?
A The reactants and product are elements.
B The reactants and product are gases.
C The reactants and product are compounds.
D The reactants are both obtained from the air.
20
The diagram shows a flow chart for the
manufacture of fertiliser.
In the flow chart, what are W, X, Y
and Z?
|
|
W |
X |
Y |
Z |
|
A B C D |
H2 O2 O2 N2 |
N2 SO2 SO2 H2 |
high high low high |
NH3
SO3
SO3 NH3 |
21
In a closed system a reversible reaction will
form an equilibrium mixture.
(a) Which of the following statements are true for a reversible reaction at equilibrium? Tick (✓) the two correct answers.
The rate of the forward reaction is faster than the rate of the
backward reaction.
The position of equilibrium will not change if more product is
added.
The concentration of the reactants does not change.
The rate of the forward reaction is the same as the rate of the
backward reaction.
The concentration of the reactants is the same as the concentration
of the products.
The position of equilibrium moves to the left when product is
removed from the equilibrium.
[2]
(b) 
Methane is a fuel that can be made by
the reaction between carbon dioxide and hydrogen.
CO2(g) + 4H2(g) <=> CH4(g) + 2H2O(g)
Paul predicts that
•
the reaction is exothermic
•
there are more moles of gas on the right-hand side of the equation.
Look at the two graphs.
Do the graphs support Paul’s predictions? Explain your answer.
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[1]
(b) Ammonia is produced in industry by the Haber process which is illustrated in the diagram below.
(i)
Name the gas X used in the Haber process.
[1]
(ii)
Name the gas Y used in the Haber process.
[1]
(iii) State
the pressure to which the gases are compressed.
[1]
(iv)
Write a balanced
symbol equation for the reaction which occurs in the reactor.
[3]
(v)
Name the catalyst used in the reactor.
[1]
(vi)
State the temperature used in the reactor.
[1]
(vii) Choose
the correct word from the box below to complete the sentence.
In the condenser, the gases are to
separate ammonia as a liquid.
[1]
23
Nitrogenous fertilisers contain ammonium
compounds such as ammonium nitrate
which is produced when ammonia reacts with nitric acid.
(a)
(i) Write a balanced symbol equation for the reaction of ammonia with nitric acid.
[2]
(ii)
Describe how you
would carry out a chemical test for the presence of ammonia gas, stating the
observations you would make for a
positive test.
[4]
(iii) State
one disadvantage of using nitrogenous fertilisers.
[1]
(b)
In industry ammonia
gas is produced by the Haber process which involves
a reversible reaction between the gases nitrogen and hydrogen.
N2 + 3H2 2NH3
(i)
Explain
what you understand by the term reversible reaction.
[1]
(ii) Name
the catalyst used in the Haber process.
[1]
(c)
The percentage yield
of ammonia produced in the Haber Process is
affected by both the temperature and the pressure. The graph below shows how
the percentage yield of ammonia changes with temperature and pressure.
Use
the graph to answer the following questions.
 |
[1]
(ii)
450 °C and 250 atm
are commonly used conditions for the Haber Process. What is the percentage
yield of ammonia using these conditions?
[1]
(iii) Suggest why industry uses 450 °C and 250 atm when it is possible to obtain a higher yield of ammonia using a lower temperature and a higher pressure.
 |
 |
[1]
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