EXAM CHEMICAL REACTIONS TOTAL MARKS FOR EXAM: 150
Q1.
A metal is added to copper(II) sulfate solution.
A displacement reaction only occurs if the metal added is more reactive than copper.
metal + copper(II) sulfate → metal sulfate + copper
Displacement reactions are exothermic. The more reactive the metal added, the greater the
temperature rise.
A student uses the following method in an experiment to compare the reactivities of different
metals:
· pour some copper(II) sulfate solution into a boiling tube and record its temperature using a
thermometer
· add some metal to the tube and stir with the thermometer
· record the maximum temperature of the contents of the tube.
He repeats the method using the same amount, in moles, of different metals.
(a) To make the experiment valid, he starts with the copper(II) sulfate solution and the added
metal at the same temperature.
State two other variables that must be controlled if the experiment is to be valid.
(2)
1 ..........................................................................................................................................
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2 ..........................................................................................................................................
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(b) Another student uses the same method three times for each of the metals E, F, G and H. The
table shows her results for these metals.
, (i) The student calculates the mean temperature increase for metals E and F.
She does not include anomalous values in her calculations.
Calculate the mean temperature increase for metals G and H, ignoring any anomalous
values. Write your answers in the table.
(2)
(ii) Explain which metal is the most reactive.
(2)
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(iii) Explain which metal is less reactive than copper.
(2)
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(Total for question = 8 marks)
,Q2.
Hydrogen peroxide solution decomposes slowly at room temperature to form water and oxygen.
The equation for the reaction is
2H2O2 → 2H2O + O2
(a) A catalyst increases the rate of this reaction.
State one other property of a catalyst.
(1)
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(b) A student has samples of three solids, X, Y and Z.
The student uses this apparatus to find out which solids act as catalysts in the decomposition
of hydrogen peroxide solution.
Describe the method that the student should use to find out which solids act as catalysts.
(6)
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(c) The decomposition of hydrogen peroxide solution is exothermic.
On the diagram, draw and label the reaction profiles for the reaction
· without a catalyst
· with a catalyst
(2)
(d) The equation for the reaction can be shown using displayed formulae.
The table gives the bond energies for two of the bonds.
Q1.
A metal is added to copper(II) sulfate solution.
A displacement reaction only occurs if the metal added is more reactive than copper.
metal + copper(II) sulfate → metal sulfate + copper
Displacement reactions are exothermic. The more reactive the metal added, the greater the
temperature rise.
A student uses the following method in an experiment to compare the reactivities of different
metals:
· pour some copper(II) sulfate solution into a boiling tube and record its temperature using a
thermometer
· add some metal to the tube and stir with the thermometer
· record the maximum temperature of the contents of the tube.
He repeats the method using the same amount, in moles, of different metals.
(a) To make the experiment valid, he starts with the copper(II) sulfate solution and the added
metal at the same temperature.
State two other variables that must be controlled if the experiment is to be valid.
(2)
1 ..........................................................................................................................................
.............................................................................................................................................
2 ..........................................................................................................................................
.............................................................................................................................................
(b) Another student uses the same method three times for each of the metals E, F, G and H. The
table shows her results for these metals.
, (i) The student calculates the mean temperature increase for metals E and F.
She does not include anomalous values in her calculations.
Calculate the mean temperature increase for metals G and H, ignoring any anomalous
values. Write your answers in the table.
(2)
(ii) Explain which metal is the most reactive.
(2)
.............................................................................................................................................
.............................................................................................................................................
(iii) Explain which metal is less reactive than copper.
(2)
.............................................................................................................................................
.............................................................................................................................................
(Total for question = 8 marks)
,Q2.
Hydrogen peroxide solution decomposes slowly at room temperature to form water and oxygen.
The equation for the reaction is
2H2O2 → 2H2O + O2
(a) A catalyst increases the rate of this reaction.
State one other property of a catalyst.
(1)
.............................................................................................................................................
.............................................................................................................................................
(b) A student has samples of three solids, X, Y and Z.
The student uses this apparatus to find out which solids act as catalysts in the decomposition
of hydrogen peroxide solution.
Describe the method that the student should use to find out which solids act as catalysts.
(6)
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
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, .............................................................................................................................................
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.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
(c) The decomposition of hydrogen peroxide solution is exothermic.
On the diagram, draw and label the reaction profiles for the reaction
· without a catalyst
· with a catalyst
(2)
(d) The equation for the reaction can be shown using displayed formulae.
The table gives the bond energies for two of the bonds.
