Download Name: C2 Topic 5 Date: Time: Total marks available: Total marks

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C2 Topic 5
Date:
Time:
Total marks available:
Total marks achieved: ______
Questions
Q1.
Calcium carbonate
(a) Calcium carbonate reacts with dilute hydrochloric acid.
Complete the sentence by putting a cross (
In this reaction hydrochloric acid is
) in the box next to your answer.
(1)
A precipitated
B displaced
C neutralised
D combusted
(b) The equation for the reaction is
The diagram shows the heat energy contained in the reactants and the heat energy contained in the
products.
Use the diagram to explain why this reaction is as an exothermic reaction.
(2)
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(c) If dilute hydrochloric acid is heated before calcium carbonate is added, the rate of reaction
increases.
Explain, in terms of particles, why the rate of reaction increases.
(3)
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*(d) An experiment was carried out to compare the rates of reaction between calcium carbonate and
two different concentrations of hydrochloric acid.
Describe, in detail, how you would carry out this experiment.
(6)
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Q2.
Catalytic converters in the exhaust systems of cars contain catalysts.
(i) Explain what is meant by the term catalyst.
(2)
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(ii) This reaction takes place in a catalytic converter
carbon monoxide + oxygen → carbon dioxide
This reaction is exothermic.
On the axes below, draw labelled lines to show the relative energies of the reactants and products in
this reaction.
(2)
(iii) Another reaction in a catalytic converter is the reaction of hydrocarbons with excess oxygen to form
carbon dioxide and water.
Write the balanced equation for the reaction of the hydrocarbon heptane, C7H16, with excess oxygen.
(3)
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Q3.
(a) An experiment is carried out to measure the temperature change when solid ammonium chloride is
dissolved in water.
initial temperature of water = 19°C
final temperature of solution = 15°C
Explain what the temperature readings show about the type of heat change occurring when ammonium
chloride dissolves in water.
(2)
(b) When zinc reacts with copper sulfate solution, copper and zinc sulfate solution are formed.
Zn + CuSO4 Cu + ZnSO4
This reaction is exothermic.
Use this information to complete the diagram.
(2)
(c) Reactions are accompanied by heat changes.
The heat changes are the results of bonds being broken and bonds being formed.
Which row of the table shows the heat energy changes that occur when bonds are broken and when
bonds are formed?
Put a cross (
) in the box next to your answer.
(1)
*(d) Reactions can occur when particles collide.
Rates of reactions can be altered by changing conditions.
Explain how the rate of reaction between a solid and a liquid is altered by changing the size of the
pieces of solid and by changing the temperature of the liquid.
(6)
(Total for Question is 11 marks)
Q4.
A student investigated the rate of a reaction.
The student investigated the reaction between zinc and dilute sulfuric acid.
The products are zinc sulfate, ZnSO4, and hydrogen.
(i) Write the balanced equation for this reaction.
(2)
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*(ii) The student carried out two experiments.
The same mass of zinc and the same sized pieces of zinc were used in each experiment.
The results are shown in the table.
Evaluate these results, explaining the reasons why the rate of reaction in experiment 2 is faster than
the rate of reaction in experiment 1.
In your answer you should refer to the frequency and energy of collisions between particles.
(6)
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Q5.
(a) Zinc is a metal.
Zinc reacts with dilute hydrochloric acid to produce zinc chloride and hydrogen.
Edward used this apparatus to investigate the speed of the reaction between zinc and dilute hydrochloric
acid.
(i) Edward's results for 50 °C are shown on the graph.
Sketch a line on the graph to show the results that Edward should expect to obtain if he carried out the
experiment to completion at 30 °C.
(2)
(ii) When zinc powder is used, instead of larger pieces of zinc, the reaction is faster.
Explain, using ideas about particles, why the reaction is faster when zinc powder is used.
(2)
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(iii) Balance the equation for the reaction of zinc with dilute hydrochloric acid by putting a number in the
space
provided.
(1)
Zn + . . . . . . . . . . . . . HCl → ZnCl2 + H2
(iv) The reaction between zinc and dilute hydrochloric acid is exothermic.
Explain, in terms of breaking and forming bonds, why this reaction is exothermic.
(3)
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(b) Catalysts are added to some reactions.
State the effect of catalysts on reactions.
(1)
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(Total for Question is 9 marks)
Q6.
The apparatus shown was used by a student to investigate the reaction between strips of magnesium
ribbon and excess dilute hydrochloric acid.
The word equation for the reaction is
(a) States of substances in reactions can be shown by state symbols.
Explain the difference between magnesium chloride(aq) and magnesium chloride(l).
(2)
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(b) Describe what you would see when magnesium ribbon reacts with dilute hydrochloric acid.
(1)
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(c) Every 20 seconds, the student recorded the total volume of hydrogen produced in the reaction.
(i) Name a piece of apparatus the student should use to measure the volume of hydrogen produced.
(1)
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The results are shown on the graph.
(ii) After how many seconds had all the magnesium reacted?
(1)
........................................................... seconds
(iii) The experiment is repeated using the same volume of a more concentrated hydrochloric acid
solution.
All other conditions were kept the same.
On the graph draw a curve to show how the volume of hydrogen changes with time during this
experiment.
(2)
(d) A student repeated the original experiment using the same mass of magnesium as a powder instead
of as ribbon.
All other conditions were the same as in the first experiment.
Explain the effect on the rate of reaction of using magnesium powder instead of magnesium ribbon.
(2)
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(e) When magnesium reacts with dilute hydrochloric acid there is a change in temperature.
In an experiment the results were
temperature at start = 21 °C
temperature at end = 62 °C
Explain what conclusion can be made about the type of reaction, from these results.
(2)
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Q7.
Rates of reactions and energy changes
(a) Marble chips react with hydrochloric acid to produce carbon dioxide.
The equation for the reaction is
CaCO3 + 2HCl → CaCl2 + H2O + CO2
Which one of these changes would decrease the rate of this reaction?
Put a cross (
) in the box next to your answer.
(1)
A
use hydrochloric acid which is more dilute
B
use smaller sized marble chips
C
use marble chips which have a larger surface area
D
use a larger volume of the hydrochloric acid
(b) Explain why increasing the temperature of a reaction increases the rate of the reaction.
(2)
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(c) (i) The rate of decomposition of hydrogen peroxide can be increased by adding a catalyst.
Which of these graphs shows the mass of the catalyst during the reaction?
Put a cross (
) in the box next to your answer.
(1)
(ii) The decomposition of hydrogen peroxide, H2O2, produces oxygen and water.
Give the balanced equation for this reaction.
(2)
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(d) Explain, in terms of the energy involved in the breaking of bonds and in the making of bonds, why
some reactions are exothermic.
(2)
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(Total for question = 8 marks)
Q8.
(a) A technician made some dilute sodium hydroxide solution by carefully adding some solid sodium
hydroxide to pure water.
This is the hazard symbol on a bottle of solid sodium hydroxide.
(i) State what this symbol shows about sodium hydroxide.
(1)
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(ii) Sodium hydroxide solution reacts with dilute hydrochloric acid.
During the reaction heat is released.
What type of reaction is this?
Put a cross (
) in the box next to your answer.
(1)
A displacement
B endothermic
C neutralisation
D precipitation
(b) A catalyst is added to some reactions.
Explain the meaning of catalyst.
(2)
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(c) Dilute hydrochloric acid reacts with calcium carbonate to produce carbon dioxide gas.
Three different experiments were carried out using large pieces of calcium carbonate, small pieces of
calcium carbonate and powdered calcium carbonate.
The size of the calcium carbonate pieces was the only factor that was changed.
In each experiment the volume of carbon dioxide released in five minutes was measured.
The results are
Describe what this shows about the effect of the surface area of calcium carbonate on the rate of this
reaction.
(2)
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*(d) Hydrochloric acid reacts with magnesium metal to produce hydrogen gas.
magnesium + hydrochloric acid → magnesium chloride + hydrogen
Describe how you could use magnesium ribbon and a solution of hydrochloric acid to show that
decreasing the concentration of the hydrochloric acid changes the rate of this reaction.
(6)
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(Total for Question = 12 marks)
Q9.
(a) A student investigated the rate of a reaction.
The student investigated the reaction between zinc and dilute sulfuric acid.
The products are zinc sulfate, ZnSO4, and hydrogen.
(i) Write the balanced equation for this reaction.
(2)
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*(ii) The student carried out two experiments.
The same mass of zinc and the same sized pieces of zinc were used in each experiment.
The results are shown in the table.
Evaluate these results, explaining the reasons why the rate of reaction in experiment 2 is faster than
the rate of reaction in experiment 1.
In your answer you should refer to the frequency and energy of collisions between particles.
(6)
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(b) Zinc is reacted with copper sulfate solution.
The equation for the reaction is
Zn(s) + CuSO4(aq) → ZnSO4(aq) + Cu(s)
(i) What type of reaction is this?
(1)
Put a cross (
) in the box next to your answer.
A decomposition
B displacement
C dissolving
D neutralisation
(ii) This reaction is exothermic.
On the diagram below draw labelled lines to show the relative energies of the reactants and products in
this reaction.
(2)
(Total for Question = 11 marks)
Q10.
Zinc is a metal.
Zinc reacts with dilute hydrochloric acid to produce zinc chloride and hydrogen.
Edward used this apparatus to investigate the speed of the reaction between zinc and dilute hydrochloric
acid.
(i) Edward's results for 50 °C are shown on the graph.
Sketch a line on the graph to show the results that Edward should expect to obtain if he carried out the
experiment to completion at 30 °C.
(2)
(ii) When zinc powder is used, instead of larger pieces of zinc, the reaction is faster.
Explain, using ideas about particles, why the reaction is faster when zinc powder is used.
(2)
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(iii) Balance the equation for the reaction of zinc with dilute hydrochloric acid by putting a number in the
space
provided.
(1)
Zn + . . . . . . . . . . . . . HCl → ZnCl2 + H2
(iv) The reaction between zinc and dilute hydrochloric acid is exothermic.
Explain, in terms of breaking and forming bonds, why this reaction is exothermic.
(3)
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Mark Scheme
Q1.
Question
Number
(a)
Acceptable answers
(b)
Answer
Acceptable answers
An explanation
linking the following
points • products (of
reaction) contain less
heat energy than
reactants (1)
• difference in heat
energies given out
(1)
Question
Number
Mark
(1)
C
Question
Number
(c)
Answer
Answer
An explanation
linking three of the
following points
• particles have
more energy (1)
• (therefore) move
faster (1)
• (therefore) more
frequent collisions
(1) • (therefore)
more energetic
collisions (1)
• (therefore) more
collisions result in
Mark
(2)
Acceptable answers
Mark
(3)
reaction / are
successful (1)
QWC
Question
Number
*(d)
Level
1
0
1-2
2
3-4
3
5-6
Indicative content
Mark
A description
including some of
the following points
• known mass of
calcium carbonate
• known volume of
hydrochloric acid
• mix • determine
how fast reaction is
by suitable
measurements
(repeat with)
• same mass of
same calcium
carbonate • same
volume of acid of
different
concentration • at
same temperature
• determine how
fast reaction is
• compare results of
(6)
experiments
No rewardable material
• a limited description of how to carry out
the basic experiment / some relevant facts to
carry out the experiment • the answer
communicates ideas using simple language
and uses limited scientific terminology
• spelling, punctuation and grammar are
used with limited accuracy • spelling,
punctuation and grammar are used with
limited accuracy
• a possibly incomplete description of a
workable experiment indicating control of at
least one variable / a limited attempt at the
former with some comparison of the results
• the answer communicates ideas showing
some evidence of clarity and organisation
and uses scientific terminology appropriately
• spelling, punctuation and grammar are
used with some accuracy
• a clear description of a workable
experiment indicating the control of most
variables and how the correct comparison
will be obtained • the answer
communicates ideas clearly and coherently
uses a range of scientific terminology
accurately • spelling, punctuation and
grammar are used with few errors
Q2.
Q3.
Answer
(a)
(b)
(c)
An explanation
linking two of the
following
temperature
decreases (1)
heat / energy
taken in (1)
(so process)
endothermic (1)
Shown correctly on
diagram: horizontal
line to right of
reactant (1)
product line below
reactant line (1)
D : heat energy is
required heat energy
is released
Acceptable
answers
(2)
ignore references to
bond breaking /
making heat given
out / exothermic = 1
max.
(2)
ignore any
connecting lines
product label not
needed
(1)
Indicative Content
*(d)
Mark
An explanation
including some of
the following points
smaller pieces of
solid
of same mass
larger surface
area
more frequent
collisions
higher rate of
Mark
(6)
Level
1
0
1-2
reaction higher
temperature
particles move
faster
more frequent
collisions
particles have
more energy
more collisions
have required
energy to react /
activation energy
more collisions
successful
higher rate of
reaction ORA
No rewardable content
 a limited explanation of one of factors
e.g. at higher temperature higher rate
e.g. when particles smaller size higher rate
 the answer communicates ideas using
simple language and uses limited scientific
terminology
 spelling, punctuation and grammar are
used with limited accuracy
2
3-4
 a simple explanation e.g. at higher
temperature particles move faster, more
collisions so higher rate
e.g. smaller sized particles (of same mass)
have greater surface area so higher rate
 the answer communicates ideas
showing some evidence of clarity and
organisation and uses scientific terminology
appropriately
 spelling, punctuation and grammar are
used with some accuracy
3
5-6
 a detailed explanation e.g. (when
particles collide they) only react when they
have sufficient energy/activation energy and
at a higher temperature more of the particles
have sufficient energy/activation energy so
more collisions will be successful and when
particles smaller size higher rate
 the answer communicates ideas clearly
and coherently uses a range of scientific
terminology accurately
 spelling, punctuation and grammar are
used with few errors
Q4.
Answer
(i)
QWC
Zn +H2SO4 →ZnSO4
+ H2
reactants (1)
products (1)
*(ii)
Acceptable
answers
Accept multiples
If not correctly
balanced max 1
Must be subscripts
where relevant
Mark
Indicative Content
Mark
A description
including some of
the following points
general points
 reactions occur
when particles
collide
 more frequent
collisions cause
higher rate of
reaction
 mass and size of
zinc pieces same so
no effect on rate of
reaction
 because same
surface area
 two factors have
been altered in the
same experiment
 cannot be certain
of effect of
eachconcentration
 experiment 2
higher/triple
concentration of acid
 so more particles
(in same volume)
 so more frequent
collisions between
particles
 more successful
collisionstemperatur
e
 experiment 2
higher temperature
 particles move
faster
 particles have
more energy
 so more frequent
collisions between
particles (so
increased rate)
 more successful
collisions
(6)
(2)
Level
1
2
0
1-2
3-4
 so more
energetic collisions
between particles
 more particles
have enough energy
to react (activation
energy) when they
collide
No rewardable content
 a limited description e.g. temperature is
higher and concentration is higher so
reaction is faster
e.g. temperature is higher so particles move
faster so reaction is faster
 the answer communicates ideas using
simple language and uses limited scientific
terminology
 spelling, punctuation and grammar are
used with limited accuracy
a simple description
e.g. temperature is higher so particles move
faster and concentration is higher so more
particles so reaction is faster
eg when concentration is higher there will
be more particles so more frequent collisions
so faster reaction
e.g. when temperature is higher particles
move faster so more successful collisions so
faster reaction
 the answer communicates ideas
showing some evidence of clarity and
organisation and uses scientific terminology
appropriately
 spelling, punctuation and grammar are
used with some accuracy
3
5-6
 a detailed description e.g. higher
concentration of acid so more particles so
more frequent collisions so faster reaction
and higher temperature so particles have
more energy so more successful collisions
so faster reaction
 the answer communicates ideas clearly
and coherently uses a range of scientific
terminology accurately
 spelling, punctuation and grammar are
used with few errors
Q5.
Answer
(a)(i)
(a)(ii)
(a)(iii)
(a)(iv)
(b)
Q6.
Independent marking
points
 a curve/line
starting at the origin
showing a lower
gradient than the 50°
curve (1)
 levels out at the
same volume as the
50° curve (1)
An explanation
linking the following
 (zinc powder)
has a larger surface
area (1)
 therefore there
are more (frequent)
collisions (between
the particles) (1)
2
An explanation
linking the following
 breaking bonds
requires/needs
heat/energy /
breaking bonds is an
endothermic process
(1)
 forming bonds
produces/releases
heat/energy / forming
bonds is an
exothermic process
(1)
 more
heat/energy is given
out than is taken in
(1)
makes the reaction
go faster/increases
speed/increase rate
Acceptable
answers
Mark
(2)
reject particle size is
smaller more
particles in contact
more successful
collisions reject
increase in energy
for 2nd marking point
(2)
(1)
(3)
lower activation
energy
(1)
Q7.
Q8.
Answer
(a)(i)
(a)(ii)
(b)
(c)
QWC
corrosive
C neutralisation
An explanation to
include
 (substance that)
increases rate /
speeds up reaction
(1)
 without being
used up / changed
itself (1)
A description to
include
 smaller pieces
have larger surface
area / ORA (1)
 larger surface
area, higher / faster
rate (1)ORA
*(d)
Acceptable
answers
damages skin /
clothes causes burns
Mark
(1)
(1)
ignore slows down a
reaction lowers
activation energy
reject provides
energy / heat (for 2nd
mark)
(2)
smallerpieces give
fasterrate (1) ORA
allow 'bigger surface
area produces more
carbon dioxide' (or
similarly phrased) for
one mark
(2)
Indicative Content
Mark
A description /
comparison/
explanation / etc
including some of
the following points
method – what
needs to be carried
out
 dilute the acid
 (to make)
different
concentrations /
stated concentration
values
 add magnesium
to acid
 in suitable
container
 equal volumes of
the acids
 equal lengths of
magnesium
observations – to
make
 observe/ count
bubbles
 highest
concentration
magnesium reacts,
lowest concentration
magnesium does not
(6)
Level
1
0
1-2
react
 observe/ time
magnesium
disappearing
 use of timer
 measure volume
gas produced
 measure
decrease in
massconclusion –
evidence gathered
or seen
 formed bubbles
faster
 magnesium
disappears faster
 gas produced
faster
 mass lost faster
No rewardable content
 a limited description e.g. add magnesium
to acid and time the reaction
 the answer communicates ideas using
simple language and uses limited scientific
terminology
 spelling, punctuation and grammar are
used with limited accuracy
2
3-4
 a simple description e.g. dilute the acid,
add magnesium to both acid solutions and
more concentrated one bubbles faster or
magnesium reacts quicker
 the answer communicates ideas
showing some evidence of clarity and
organisation and uses scientific terminology
appropriately
 spelling, punctuation and grammar are
used with some accuracy
3
5-6
 a detailed description e.g. add
magnesium to different concentrations of
acids in beakers: lower concentration longer
time therefore slower reaction
 the answer communicates ideas clearly
and coherently uses a range of scientific
terminology accurately
 spelling, punctuation and grammar are
used with few errors
Q9.
Answer
(a)(i)
QWC
Zn +H2SO4 →ZnSO4
+ H2
reactants (1)
products (1)
*(a)(ii)
Acceptable
answers
Accept multiples
If not correctly
balanced max 1
Must be subscripts
where relevant
Mark
Indicative Content
Mark
A description
including some of
the following points
general points
 reactions occur
when particles
collide
 more frequent
collisions cause
higher rate of
reaction
 mass and size of
zinc pieces same so
no effect on rate of
reaction
 because same
surface area
 two factors have
been altered in the
same experiment
 cannot be certain
of effect of
eachconcentration
 experiment 2
higher/triple
concentration of acid
 so more particles
(in same volume)
 so more frequent
collisions between
particles
 more successful
collisionstemperatur
e
 experiment 2
higher temperature
 particles move
faster
 particles have
more energy
 so more frequent
collisions between
particles (so
increased rate)
 more successful
collisions
(6)
(2)
Level
1
0
1-2
2
3-4
 so more
energetic collisions
between particles
 more particles
have enough energy
to react (activation
energy) when they
collide
No rewardable content
 a limited description e.g. temperature is
higher and concentration is higher so
reaction is faster
e.g. temperature is higher so particles move
faster so reaction is faster
 the answer communicates ideas using
simple language and uses limited scientific
terminology
 spelling, punctuation and grammar are
used with limited accuracy
a simple description
e.g. temperature is higher so particles move
faster and concentration is higher so more
particles so reaction is faster
eg when concentration is higher there will
be more particles so more frequent collisions
so faster reaction
e.g. when temperature is higher particles
move faster so more successful collisions so
faster reaction
 the answer communicates ideas
showing some evidence of clarity and
organisation and uses scientific terminology
appropriately
 spelling, punctuation and grammar are
used with some accuracy
3
5-6
 a detailed description e.g. higher
concentration of acid so more particles so
more frequent collisions so faster reaction
and higher temperature so particles have
more energy so more successful collisions
so faster reaction
 the answer communicates ideas clearly
and coherently uses a range of scientific
terminology accurately
 spelling, punctuation and grammar are
used with few errors
Answer
(b)(i)
(b)(ii)
B displacement
Shown on diagram
 horizontal
reactant line above
product line (1)
Acceptable
answers
Mark
(1)
lines must be
correctly labelled
eg reactants/Zn +
CuSO4 and products/
(2)
 horizontal
product line to right
of reactant line (1)
CuSO4 and Cu
ignore any extra
lines/curves/labels if
not drawn lines but
just labels in correct
relative positions
max 1 If two lines
drawn in correct
positions but no
labels max 1
Q10.
Answer
(i)
(ii)
(iii)
(iv)
Independent marking
points
 a curve/line
starting at the origin
showing a lower
gradient than the 50°
curve (1)
 levels out at the
same volume as the
50° curve (1)
An explanation
linking the following
 (zinc powder)
has a larger surface
area (1)
 therefore there
are more (frequent)
collisions (between
the particles) (1)
2
An explanation
linking the following
 breaking bonds
requires/needs
heat/energy /
breaking bonds is an
endothermic process
(1)
 forming bonds
produces/releases
heat/energy / forming
bonds is an
exothermic process
(1)
 more
heat/energy is given
out than is taken in
(1)
Acceptable
answers
Mark
(2)
reject particle size is
smaller more
particles in contact
more successful
collisions reject
increase in energy
for 2nd marking point
(2)
(1)
(3)