Investigating Rates of Reaction
Aim
This resource covers a series of 5 lessons during which time students will investigate 5 factors
affecting the rate of a chemical reaction, and three methods of investigating rates of reaction. They
will be challenged to observe and identify the causes and effects of these factors, as well as to
apply How Science Works skills including graph drawing and interpretation, description and
explanation of observations.
Learning Outcomes
Each practical has it’s own learning outcomes, specified below. In addition the following learning
outcomes apply:
Define rate of reaction
Define collision theory
List ways of finding the rate of a reaction
Explain why a particular method of finding the rate is suitable for a specified reaction
Administration
Students should work in pairs, and the class should be split into 4 groups. Groups should work on
a different practical task, and should rotate through each over 4 hours of lesson time.
This should alleviate pressure on equipment, and should allow all students to participate equally.
Students will need copies of the instruction sheets and graph paper.
Students should be reminded of all safety implications before every session. Some techniques will
need to be demonstrated before students attempt them (e.g. use of gas syringes).
Suggested timetable:
Lessons 1-4: practical tasks on rotation (sheets attached). Students should be encouraged to work
independently, to identify patterns in reactivity under the different conditions. They should be
encouraged to think about why changing conditions causes the differences they observe. Allow
students to come to their own conclusions, but facilitate with questioning – encourage them to
think critically about their work.
Lesson 5: This lesson should serve as a synoptic session, identifying students ideas about the
rates of reaction and introducing collision theory in a more formalised way. Following this, it may
be useful for students to return to the explanation part of the practical sheets to include details of
collision theory in their explanations of their observations.
Name: __________________________
Date: ____________________________
Specification Link:
AQA GCSE Chemistry C2.4 Rates of Reacton
Edexcel GCSE C2 Chemical Reactions
OCR GCSE 21st Century Chemistry A C6 Chemical Synthesis
OCR GCSE Gateway Chemistry B C3 Chemical Economics
Safety:
The teacher should ensure students observe the usual lab safety precautions, with consideration
for any additional aspects the group in question might require.
Hazcards:
50
Hydrogen peroxide Harmful
60
Manganese and its compounds
47A
Hydrochloric acid
95C
Sodium thiosulfate
19B
Calcium an strontium salts (2) Low Hazard
Harmful
Corrosive
Name: __________________________
Date: ____________________________
Equipment
Practical station:









A
B
Effect of catalysts
Effect of temperature
Hydrogen peroxide
Manganese(IV)
oxide
Finely chopped
potato
Finely chopped
liver
Stopwatches (4)
Conical flasks (4)
Gas syringes with
bungs & tubing(4)
Clamps & stands
Measuring
cylinders (25cm3)

Hydrochloric acid
(0.2mol/dm3)
 Sodium thiosulfate
(0.2mol/dm3)
 Stopwatches (4)
 Conical Flasks (4)
 Water baths at 30,
40 & 50°C
 Ice bath
 Measuring
cylinders (10cm3)
 Cotton wool
 Thermometers
Please set up with
samples of both
solutions in each
water/ice bath.
C
Effect of
concentration/pressure
 Hydrochloric acid
(0.2mol/dm3, 0.5
mol/dm3 &
1mol/dm3)
 Marble chips
 Stopwatches (4)
 Conical Flasks (4)
 Top pan balances
(4)
 Measuring
cylinders (25cm3)
 Cotton wool
D
Effect of surface area








Hydrochloric acid
(1mol/dm3)
Marble chips (small
& large)
Stopwatches (4)
Conical Flasks (4)
Top pan balances
(2)
Gas syringes with
bungs & tubing(4)
Clamps & stands
Measuring
cylinders (25cm3)
Learning Objectives
Effect of
Effect of surface area
concentration/pressure
State what effect
Describe how
increasing the
Describe how
increasing the
pressure of
surface area
| Define catalyst
||| temperature
|
|||
reacting gases
affects the rate of
affects the rate of
has on the rate of
reaction
reactions
reaction
Apply collision
Describe the
Apply collision
theory to explain in
effect of
theory to explain
Describe how a
detail how and why
increasing
in detail how

||| catalyst affects the 
|||
temperature
concentration on
surface area
rate of a reaction
changes the rate
the rate of
affects the rate of
of reaction
reaction
reaction
Apply collision
Explain in detail
Predict how
theory to explain
Suggest which
why a catalyst
temperature would
in detail the effect
collisions would
 would be used in
 affect a reaction
 of changing

not cause a
an industrial
where particles are
concentration or
reaction
process
in a solid state
pressure on the
rate of reaction
Effect of catalysts
Effect of temperature
Name: __________________________
Date: ____________________________
Experiment A - Measuring the effect of a catalyst on the rate of a reaction
Equipment:
 Hydrogen peroxide
 Manganese(IV) oxide
 Potato
 Liver (optional)
 Stopwatch
 Gas syringe & delivery
tubes
 Conical flask
 25cm3 measuring cylinder
 Clamp & stand
 Safety spectacles
Results:
Time (s)
Procedure:
1. Set up the gas syringe and delivery tubes in a clamp &
stand.
Gas syringes are delicate, you must have their use
demonstrated.
2. Add 25cm3 hydrogen peroxide to the conical flask
3. Add finely chopped potato
4. Swiftly and carefully connect the flask to the gas syringe
5. Start the stopwatch
6. Record the volume of gas released every 10 seconds
for 2 minutes.
7. Repeat with a spatula of manganese(IV) oxide and then
chopped liver (optional)
Draw and label a diagram of your experiment.
3
Volume of gas produced (cm )
Potato
Liver
MnO2
0
10
20
30
40
50
60
70
80
90
100
110
120
Plot these results on a graph.
Variables:
Independent variable:
Dependent variable:
Control variables:
Describe your results:
Explain what caused the observed effects:
Name: __________________________
Date: ____________________________
Experiment B - Measuring the effect of temperature on the rate of a reaction
Equipment:
 Hydrochloric acid
(0.2mol/dm3)
 Sodium thiosulfate
(0.2mol/dm3)
 Stopwatch
 Conical Flask
 Water baths at 30, 40 &
50°C
 Ice bath
 Measuring cylinder
(10cm3)
 Cotton wool
 Thermometer
Results:
Procedure:
1. Place 10cm3 of room temperature 0.2mol/dm3
hydrochloric acid into a conical flask
2. Record the temperature of the solutions
3. Draw an X with a pencil on a piece of plain paper &
place underneath the conical flask
4. Add 10cm3 of sodium thiosulfate
5. Start the stopwatch
6. Record how long it takes for the X to be obscured
7. Repeat the experiment with reactants at different
temperatures
Draw and label a diagram of your experiment.
Temp of
solutions
(°C)
Time taken
for solution
to go
cloudy (s)
Plot these results on a graph.
Variables:
Independent variable:
Dependent variable:
Control variables:
Describe your results:
Explain what caused the observed effects:
Name: __________________________
Date: ____________________________
Experiment C – Measuring the effect of concentration on the rate of a reaction
Equipment:
Procedure:
1. Add about 5 marble chips to the conical flask
 Hydrochloric acid
2. Add 25cm3 of 0.5 mol/dm3 hydrochloric acid
(0.2mol/dm3, 0.5 mol/dm3
3. Place a plug of cotton wool in the neck of the flask
& 1mol/dm3)
4. Place the flask on the balance, record the mass and
 Marble chips
start the stopwatch.
 Stopwatch
5. Record the mass every 10 seconds for 2 minutes.
 Conical Flask
6. Repeat for 0.2mol/dm3 and 1mol/dm3 concentrations of
 Top pan balance
hydrochloric acid.
 Measuring cylinder
3
(25cm )
 Cotton wool
Results:
Draw and label a diagram of your experiment.
Mass of reaction vessel (g)
Time
(s)
0.5mol/dm3 0.2mol/dm3 1mol/dm3
0
10
20
30
40
50
60
70
80
90
100
110
120
Plot these results on a graph.
Variables:
Explain what caused the observed effects:
Independent variable:
Dependent variable:
Control variables:
Describe your results:
Name: __________________________
Date: ____________________________
Experiment D – Measuring the effect of surface area on the rate of a reaction
Equipment:
Procedure:
1. Set up the gas syringe and delivery tubes in a clamp &
 Hydrochloric acid
stand.
(1mol/dm3)
Gas
syringes are delicate, you must have their use
 Marble chips (small &
demonstrated.
large)
2. Add 1g of marble chips to the conical flask
 Stopwatch
3. Add 25cm3 hydrochloric acid
 Conical Flask
4. Connect the gas syringe and start the stopwatch
 Top pan balance (shared)
5. Record the volume of gas produced every 10 seconds
 Gas syringes with bungs &
for 2 minutes.
tubing
6. Repeat for different sized marble chips
 Clamps & stands
 Measuring cylinders
(25cm3)
Results:
Draw and label a diagram of your experiment.
Volume of gas produced (cm3)
Time
(s)
Small chips Large chips Powdered
0
10
20
30
40
50
60
70
80
90
100
110
120
Plot these results on a graph.
Variables:
Explain what caused the observed effects:
Independent variable:
Dependent variable:
Control variables:
Describe your results:
Name: __________________________
Date: ____________________________