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Form 5 Chapter 1
CHAPTER 1 : RATE OF REACTION
ANALYSIS OF PAST YEAR QUESTIONS FROM 2003 – 2008
Year
Paper
No.
Type of
question
Question
No
2003
P2
S
2004
P3
E
S
1
1
P2
E
S
2005
P3
E
S
P2
E
S
2006
P3
E
S
7
P2
E
S
3*
6
2007
P3
E
S
P2
E
S
2008
P3
E
10
S
P2
E
S
P3
E
S
E
5
STRUCTURED QUESTIONS
1. SPM 2006/P2/Q6
Diagram 6 shows two experiments to investigate one factor that influence the rate of a reaction.
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Form 5 Chapter 1
(a) What is the factor that influences the rate of reaction in both experiment?
……………………………………………………………………………………………………………
[1 mark]
(b) The reaction in the experiment is represented by the following equation :
CaCO3(s) + 2HCl(aq) → CaCl2(aq) + CO2(g) + H2O(l)
(i)
Among the products stated in the equation, which is the most suitable to be chosen to
determine the rate of reaction?
……………………………………………………………………………………………………..
[1 mark]
(ii)
(c)
State one reason for choosing the product in 6(b)(i).
……………………………………………………………………………………………………..
[1 mark]
State two controlled variables in both experiments.
1………………………………………………………………………………………………………….
2………………………………………………………………………………………………………….
[2 marks]
(d) The result for both experiments are represented by Graph 6.
Graph 6
Based on Graph 6 :
(i)
Experiment II has a higher rate of reaction.
How does the graph show this?
……………………………………………………………………………………………………..
……………………………………………………………………………………………………..
[1 mark]
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(ii)
Form 5 Chapter 1
What has happened to the reactants at time x?
……………………………………………………………………………………………………..
……………………………………………………………………………………………………..
[1 mark]
(iii)
Why are both curves at the same level after time x?
………………………………………………………………………………………………………
(e)
………………………………………………………………………………………………………
[1 mark]
What is the conclusion for both experiments?
………………………………………………………………………………………………………
………………………………………………………………………………………………………
[1 mark]
(f)
Another experiment is carried out using excess calcium carbonate powder and dilute
hydrochloric acid with different concentrations.
Sketch the curve of concentration of dilute hydrochloric acid against the time taken to collect a
fixed quantity of the product.
Concentration of dilute
hydrochloric acid
Time taken to collect a fixed
quantity of product
[2 marks]
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Form 5 Chapter 1
2. SPM 2008/P2/Q5
An experiment is carried out to investigate the rate of reaction of zinc with hydrochloric acid. Excess
zinc powder is added to 20 cm3 of 0.2 mol dm-3 hydrochloric acid. The volume of gas collected at
regular intervals is shown in Diagram 5.1.
Diagram 5.1
(a) State the meaning of the rate of reaction.
……………………………………………………………………………………………………...........
[1 mark]
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Form 5 Chapter 1
(b) From the graph in Diagram 5.1, determine :
(i)
The rate of reaction at 120 s.
………………………………………………………………………………………………………
[2 marks]
(ii)
(c)
The average rate of reaction between 60 s and 120 s.
………………………………………………………………………………………………………
[1 mark]
Explain why the rate of reaction decreases with time.
……………………………………………………………………………………………………...........
[1 mark]
(d) Another experiment is carried out to study the factors that affect the rate of the reaction. The
result of this experiment is shown in Diagram 5.2. Curve I represents the result of this
experiment using excess zinc powder and 50 cm3 of 1.0 mol dm-3 dilute hydrochloric acid.
Diagram 5.2
(i)
Suggest the factors that influence the rate of reaction to obtain the curves labeled II and
III.
Curve II : …………………………………………………………………………………………..
(ii)
Curve III : …………………………………………………………………………………............
[2 marks]
Describe briefly how to carry out the experiment to obtain the curve labeled III.
………………………………………………………………………………………………………
………………………………………………………………………………………………………
………………………………………………………………………………………………………
………………………………………………………………………………………………………
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(iii)
Form 5 Chapter 1
[3 marks]
Give one reason why the final volume of gas obtained in curve III is half the final volume of
gas in curve I.
……………………………………………………………………………………………………...
……………………………………………………………………………………………………...
[1 mark]
3. SPM 2003/P3/Q1
An experiment was conducted to find out the effects of temperature on the rate of reaction. 50 cm 3 of
sodium thiosulphate solution 0.05 mol dm-3 at 30 oC was put in into 250 cm3 conical flask. Then the
conical flask was placed on an ‘X’ sign on a piece of white paper.
10 cm3 of hydrochloric acid 1.0 mol dm-3 was added to the sodium thiosulphate solution and shaken.
At the same time, the stop watch was started. The stop watch was stopped as soon as the ‘X’ sign
was no longer visible.
The same steps of the experiment were repeated for sodium thiosulphate solution which was heated
to 35 oC, 40 oC, 45 oC and 50 oC.
Figure 1 shows the readings of the stop watch for each of the reactions at different temperatures.
(a) Record the time for each reaction in the spaces provided in Figure 1.
[3 marks]
(b) Construct a table and record temperature, time and 1/time for this experiment.
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Form 5 Chapter 1
[3 marks]
(c)
(i)
Draw a graph of temperature against 1/time on the graph paper.
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(ii)
Form 5 Chapter 1
Based on the graph in (c) (i), state the relationship between the rate of reaction and
temperature.
……………………………………………………………………………………………………….
……………………………………………………………………………………………………….
[3 marks]
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Form 5 Chapter 1
(d) Predict the time taken as soon as the sign ‘X’ to be no longer visible if this experiment is
repeated at 55o C.
………………………………………………………………………………………………………………
[3 marks]
(e) (i)
State the variable involved in this experiment.
Manipulated :
………………………………………………………………………………………………………
Responding variable :
………………………………………………………………………………………………………
Constant variable :
………………………………………………………………………………………………………
[3 marks]
(ii)
State how you would manipulate one variable while keeping the other variables constant.
………………………………………………………………………………………………………
………………………………………………………………………………………………………
………………………………………………………………………………………………………
[3 marks]
(f)
State the hypothesis for this experiment.
…………………………………………………………………………………………………………….
…………………………………………………………………………………………………………….
[3 marks]
(g) From the above experiment, the student found a relationship between temperature and rate of
reaction. The same situation can be applied in our daily lives, for example, keeping food that is
easily spoiled in the refrigerator.
Using your knowledge of chemistry, state the relationship between temperature and the rate at
which food turns bad.
…………………………………………………………………………………………………………….
…………………………………………………………………………………………………………….
[3 marks]
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Form 5 Chapter 1
CHAPTER 1 : RATE OF REACTION
1. SPM 2006/P2/Q6
(a) Total surface area of reactant
(b) (i)
(ii)
(c)
Carbon dioxide, CO2.
Because the changes in the volume of CO2 can be measured easily.
1. Concentration of hydrochloric acid.
2. Temperature of the reactants.
3. Mass of calcium carbonate.
* any two
(d) (i)
(ii)
Gradient of the curve of Experiment II is steeper than the gradient of the curve of
experiment I.
All the reactants have reacted completely within time x.
(iii) Both experiments produced the same amount of products.
(e) The greater the total surface area the higher is the rate of reaction.
(f)
Concentration of dilute
hydrochloric acid
Time taken to collect a fixed
quantity of product
- descending pattern of curve
- best fit curve
2. SPM 2008/P2/Q5
(a) Change of quantity of reactant/product
Time taken
(b) (i)
(ii)
Draw the tangent at 120 s
Rate of reaction = (0.12- 0.18) cm3s-1
0.267 cm3s-1
(c) Because the concentration of hydrochloric acid decreases
(d) (i) Curve II : catalyst/ temperature
Curve III : concentration
(ii)
Repeat the experiment as in set I
Reduce the concentration of hydrochloric acid
The volume of hydrochloric acid remains unchanged
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Form 5 Chapter 1
(iii) Because the number of mole of hydrochloric acid used is half of set I
3. SPM 2003/P3/Q1
(a) t1
t2
t3
t4
t5
= 55.0 s
= 48.0 s
= 42.0 s
= 37.0 s
= 33.0 s
(b)
Temperature/ oC
30
35
40
45
50
(c)
Time/ s
55.0
48.0
42.0
37.0
33.0
1/time/ s-1
0.018
0.021
0.024
0.027
0.030
(i)
Graph :
- X and Y axes labeled and unit
- Correct scale, size more than 50%
- All points transferred correctly
- Smooth graph
(ii)
Rate of reaction is directly proportional to the temperature
(d) Time = 30.3 s
(e) (i)
(ii)
(f)
Manipulated variable : temperature of sodium thiosulphate
Responding variable : time for the ‘X’ mark disappear from sight or rate of reaction
Controlled variable : volume and concentration of acid
Heat the sodium thiosulphate solution with different temperature while the volume and
concentration of sodium thiosulphate and acid remains constant.
The higher the temperature the higher the rate of reaction
(g) The lower the temperature the lower the rate of food turns bad
3. SPM 2003/P3/Q1
(a) t1
t2
t3
t4
t5
= 55.0 s
= 48.0 s
= 42.0 s
= 37.0 s
= 33.0 s
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Form 5 Chapter 1
(b)
Temperature/ oC
30
35
40
45
50
(c)
Time/ s
55.0
48.0
42.0
37.0
33.0
1/time/ s-1
0.018
0.021
0.024
0.027
0.030
(i)
Graph :
- X and Y axes labeled and unit
- Correct scale, size more than 50%
- All points transferred correctly
- Smooth graph
(ii)
Rate of reaction is directly proportional to the temperature
(d) Time = 30.3 s
(e) (i)
Manipulated variable : temperature of sodium thiosulphate
Responding variable : time for the ‘X’ mark disappear from sight or rate of reaction
Controlled variable : volume and concentration of acid
(ii)
Heat the sodium thiosulphate solution with different temperature while the volume
and concentration of sodium thiosulphate and acid remains constant.
(f)
The higher the temperature the higher the rate of reaction
(g) The lower the temperature the lower the rate of food turns bad
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Form 5 Chapter 1
CHAPTER 1 : RATE OF REACTION
ANALYSIS OF PAST YEAR QUESTIONS FROM 2003 – 2008
Year
Paper
No.
Type of
question
Question
No
1.
2003
P2
S
2004
P3
E
S
1
1
P2
E
S
2005
P3
E
S
P2
E
S
2006
P3
E
S
7
P2
E
S
3*
6
2007
P3
E
S
P2
E
S
2008
P3
E
S
P2
E
10
S
P3
E
S
5
SPM 2003/P2/Q1 (SECTION B)
The rate of reaction is affected by several factors. One of the factors is the size of
particles.
One kilogram of meat, cut into big pieces, takes a longer time to cook compared
to one kilogram of meat cut into small pieces.
(a)
Explain the above statement based on the size of the particles.
(b)
[2 marks]
A student carried out three experiments to investigate the effects of the factors
influencing the rate of reaction. Table I shows the results of the experiments.
Experiment
I
II
III
30
40
40
50
20
15
Setup of
apparatus
Temperature/C
Time taken for
all the
magnesium to
dissolve
Table 1
(i)
Write the chemical reaction equation for the reaction between magnesium
and hydrochloric acid. Calculate the maximum volume of hydrogen gas
produced. [relative atomic mass : Mg, 24; molar gas volume ; 24 dm3 mol-1
at room condition]
[4 marks]
(ii)
Sketch the graphs for the volume of hydrogen gas against time for
Experiments I, II and III on the same axes.
[3 marks]
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2.
Form 5 Chapter 1
(iii)
Calculate the average rate of reaction for Experiment I, II and III in cm3 s-1.
[3 marks]
(iv)
Compare the rate of reaction for experiment I and Experiment II and between
Experiment II and Experiment III.
With reference to collision theory, explain why there are differences in the
rates of reaction in the experiments.
[8 marks]
SPM 2005/P2/Q7 (SECTION B)
(a)
Food stored in refrigerator lasts longer than food stored in a kitchen cabinet.
Explain why.
[4 marks]
(b)
A group of pupils carried out three experiments to investigate the factors affecting
the rate of reaction.
Table 7 shows information about the reactants and the temperature used in each
experiment.
Experiment
Reactants
I
Excess calcium carbonate chips and 30 cm3 of 0.5
mol dm-3 hydrochloric acid
Excess calcium carbonate chips and 30 cm3 of 0.5
mol dm-3 hydrochloric acid
Excess calcium carbonate powder and 30 cm3 of
0.5 mol dm-3 hydrochloric acid
II
III
Table 7
Graph 7 shows the results of these experiments.
14
Temperature
/oC
30
40
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Form 5 Chapter 1
Graph 7
(i)
Calculate the average rate of reaction for Experiment I.
[2 marks]
(ii)
Based on Table 7 and Graph 7, compare the rate of reaction between :
 Experiment I and Experiment II
 Experiment II and Experiment III
In each case explain the difference in the rate of reaction with reference to
the collision theory.
[10 marks]
(iii)
The chemical equation below shows the reaction between calcium carbonate
and hydrochloric acid.
CaCO3 + 2HCl → CaCl2 + CO2 + H2O
Given that the relative atomic mass of C=12, O=16, Ca=40 and the molar
volume of any gas is 24 dm3 mol-1 at room temperature and pressure.
Calculate the maximum volume of carbon dioxide gas produced in
Experiment II.
[4 marks]
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3.
Form 5 Chapter 1
SPM 2007/P2/Q10 (SECTION C)
Table 10 shows the data from Experiment I and Experiment that were carried out to
study the rate of reaction of zinc with two acids, P and Q.
Experiment
Reactants
I
2.6 g of zinc and 50 cm3 of
acid P 2.0 mol dm-3
Products
Zinc chloride and
hydrogen gas
2.6 g of zinc and 50 cm3 of
acid Q 2.0 mol dm-3
Zinc sulphate and
hydrogen gas
II
Observation
The temperature of
the mixture
increases
The temperature of
the mixture
increases
Table 10
(a)
(i)
(ii)
By choosing either Experiment I or Experiment II, state the name of the acid
used.
Write the chemical equation for the reaction of this acid with zinc.
[2 marks]
Draw an energy profile diagram for the reaction in 10 (a)(i).
On the energy profile diagram show the :
 Heat of reaction, ∆H
 Activation energy without catalyst, Ea
 Activation energy with a catalyst, E’a
Explain the energy profile diagram.
[10 marks]
(b)
The graph in Diagram 10 shows the results of Experiment I and Experiment II.
Diagram 10
Based on the graph :
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Calculate the average rate of reaction for either Experiment I or Experiment
II.
[2 marks]
Explain the difference in the rate of reaction between Experiment I and
Experiment II before 160 s.
Use the collision theory in your explanation.
[6 marks]
(i)
(ii)
4.
Form 5 Chapter 1
SPM 2005/P3/Q3
Choose one of the following tasks:
Tasks 1
The copper wire in an electric cable can be easily bent by hand, A one-cent
coin made of an alloy of copper with tin and zinc cannot be bent easily.
Referring to the situation above, plan a laboratory experiment to investigate
the effect of alloy formation on the hardness of a metal.
[For answer to this task, please refer to F5 Chapter 9 Manufactured Substances
In Industry]
Tasks 2
Buildings in industrial areas are more corroded than those in housing areas.
This is because the concentration of acid in rain water is higher in industrial
areas.
Referring to the situation above, plan a laboratory experiment to investigate
the effect of concentration on the rate of reaction between a named acid and a
named metal.
Your planning must include the following items:
(i)
Statements of the problem
(ii)
All the variables
(iii)
Lists of substances and apparatus
(iv)
Procedure
(v)
Tabulation of data
[17 marks]
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Form 5 Chapter 1
CHAPTER 1 : RATE OF REACTION
1.
SPM 2003/P2/Q1(SECTION B)
1. Small size has bigger total surface area
2. the rate of reaction is higher
(a)
(b)
(i)
Mg + 2HCl → MgCl2 + H2
Mole of Mg = 0.2
= 0.0083 mol
24
1 mol Mg produce 1 mol H2
Volume of H2 = 0.0083 x 24000
= 199.2 cm3
(ii)
199.2
Experiment II
Experiment I
Time/s
(iii)
(iv)
Average rate of reaction :
Experiment I = 199.2
50
= 3.984 or 4 cm3 s-1
Experiment II = 199.2
20
= 9.96 or 10 cm3 s-1
Experiment III = 199.2
15
= 13.28 or 13 cm3 s-1
1.
2.
3.
4.
5.
6.
7.
8.
9.
rate of reaction in experiment II is higher than experiment I
the temperature of experiment II is higher than experiment I
the kinetic energy of particles increase
the collision between H+ ion and magnesium occur
frequency of effective collision increase
rate of reaction in experiment III is higher than experiment II
CuSO4 is used as a catalyst in experiment III
The presence of catalyst lower the activation energy
frequency of effective collision increase
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2.
Form 5 Chapter 1
SPM 2005/P2/Q7 (SECTION B)
(a)
Refrigerator
Low temperature
Low bacterial activity
Less toxin produced by bacteria
Rate of food spoilage decreases
(b)
(i)
(ii)
Kitchen Cabinet
High temperature
High bacterial activity
More toxin produced by bacteria
Rate of food spoilage is high
Average rate of reaction for Experiment I
= 50
= 0.909 cm3s-1
55
1. The rate of reaction for Experiment II is higher than Experiment I.
2. The temperature for Experiment II is higher than Experiment I.
3. High temperature causes the reactants particles to have more kinetic
energy.
4. Hydrogen ions, H+ and calcium carbonate collide with one another
more rapidly.
5. The frequency of effective collision between hydrogen ions and
calcium carbonate increases.
6. The rate of reaction for Experiment III is higher than Experiment II.
7.
The calcium carbonate in Experiment III have a bigger total surface
area.
8. The frequency of collision between hydrogen ions and calcium
carbonate increases.
9. Therefore, hydrogen ions and calcium carbonate can collide with each
other more rapidly.
10. The frequency of effective collision between hydrogen ions and
calcium carbonate increases.
(iii)
Number of moles HCl = 0.5 x 30
1000
= 0.015 mol
2 moles of HCl produces 1 mole of CO2
Therefore, the number of moles CO2
= 0.015
2
= 0.0075 mol
Volume of CO2 = 0.0075 x 24 = 0.18 dm3
3.
SPM 2007/P2/Q10 (SECTION C)
(a)
(i)
Experiment I :
P is hydrochloric acid.
Zn + 2HCl → ZnCl2 + H2
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Form 5 Chapter 1
(ii)
1. label of energy on vertical axis
2. the position of the energy level of the reactants is higher than the
energy of the product.
3. correct position for ∆H
4. correct position for Ea
5. correct position for Ea’
1.
2.
3.
4.
5.
6.
7.
(b)
(i)
The reaction is exothermic reaction.
The reactants contains more energy than the products.
∆H is the energy difference in the reactants and in the products.
Heat given out during bond formation is greater than heat absorb during
bond breaking.
Activation energy must be overcome in order for the reaction to take
place.
The use of catalyst reduces the activation energy.
The use of a catalyst increases the frequency of effective collisions.
Experiment I
Rate = 960 cm3
240 s
= 4 cm3 s-1
Experiment II
Rate = 960 cm3
160 s
= 6 cm3 s-1
(ii)
4.
1. The rate of reaction for experiment II is higher than experiment I.
2. This is because the H2SO4 is a diprotic acid whereas HCl is monoprotic
acid.
3. Diprotic acid has higher concentration of H+ ion.
4. The frequency of collision between H+ ion and zinc in experiment II is
higher than in experiment I.
5. The frequency of effective collisions in experiment II is higher than in
experiment I.
SPM 2005/P3/Q3
Statements of problem :
(i)
Does the increase in concentration of acid will increase the rate of reaction?
(ii)
All the variables :
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Form 5 Chapter 1
Manipulated variable : concentration of acid
Responding variable : rate of reaction
Controlled variables : volume of acid, temperature.
(iii)
Lists of substances and apparatus :
Materials : hydrochloric acid with concentration 0.5 mol dm-3 and 1.0 mol
dm-3, zinc granule.
Apparatus : 100 cm3 measuring cylinder, 10 cm3 measuring cylinder,
stopwatch.
(iv)
Procedure :
1. Using a measuring cylinder, 50 cm3 of 0.5 mol dm-3 of hydrochloric
and pour into a conical flask.
2. Weigh 2 g of zinc granule and drop into the conical flask.
3. Immediately close the conical flask with the stopper connected to a
inverted burette filled with water.
4. At the same time start the stopwatch.
5. The time taken to collect 50cm3 of hydrogen gas is recorded.
6. The time required for all the metal dissolved is recorded.
7. Step 1 to 5 is repeated by replacing 1.0 mol dm-3 of hydrochloric acid.
(v)
Tabulation of data :
Concentration of acid/
mol dm-3
21
Time taken to collect 50 cm3
of the hydrogen gas