This page's specimen run (seed 20261004), written up in full, with its exam answers ticked against the mark scheme. Simulated data from the Study Hack practical engine. Get the blank write-up
Specimen lab book: Temperature changes
A4. Choose “Save as PDF” as the printer to keep a copy. Page breaks are set when it prints.
Study Hack Lab
RP 4 · Chemistry
Temperature changes
Lab book
Name
Specimen
Date
2 November 2026
Course
GCSE Chemistry
Board and specification
AQA GCSE Chemistry (8462), 4.5.1.1AQA GCSE Combined Science: Trilogy (8464), 5.5.1.1Apparatus and techniques: AT 1, AT 3, AT 5, AT 6
Run
C29HO
Status
Finished: every stage done
Exam questions
30/30 marks
Aim
Investigate how the volume of sodium hydroxide solution added to hydrochloric acid affects the temperature of the mixture, and use the graph to find the volume that neutralises the acid.
Contents
Plan and risk assessment
Apparatus
Method
Results
Graph
Analysis
Conclusion and evaluation
Make safe and clear up
Exam questions on your data
Simulated data produced by Study Hack Lab from the student's own run (seed 20261004). Every reading, value and mark here is from that run; nothing has been retyped. Layout v1, practical v2. Original material; not affiliated with AQA, which has not reviewed it.
1 Plan and risk assessment
Neutralisation is exothermic: it transfers energy to the surroundings, here the solution itself, so the temperature rises with each portion of alkali until all the acid has reacted. After the end point no more reaction happens, and the extra, cooler alkali and energy lost to the surroundings make the temperature fall. Where the two straight lines cross is the end point.
HCl(aq) + NaOH(aq) → NaCl(aq) + H₂O(l)
Variables
Independent (you change)
Volume of sodium hydroxide solution added in cm³
Dependent (you measure)
Highest temperature of the mixture in °C
Control (you keep the same)
Volume of hydrochloric acid; Concentration of the acid and the alkali; Starting temperature of the solutions; Container, lid and stirring
Prediction
When sodium hydroxide solution neutralises hydrochloric acid, what will happen to the temperature of the mixture?
It will rise: the reaction transfers energy to the surroundings (exothermic).Right first time
Your first run went from 22.8 °C to 35.0 °C. Neutralisation is exothermic: it transfers energy to the surroundings, here the solution itself, so the temperature rises.
You add the sodium hydroxide 5 cm³ at a time, up to 40 cm³. What shape will your graph of highest temperature against volume be?
It rises, then falls once all the acid has reacted.Right first time
Each portion reacts with acid and releases energy until all the acid has reacted. After that no more reaction happens: the extra alkali only adds cooler liquid, and the mixture loses energy to the surroundings, so the temperature falls.
The acid and the alkali have the same concentration. After how much sodium hydroxide will the temperature be highest?
About 30 cm³: the same volume as the acid.Right first time
Your lines crossed at 26.4 cm³. HCl + NaOH → NaCl + H₂O: one mole of acid reacts with one mole of alkali. With equal concentrations, equal volumes contain equal numbers of moles, so 30 cm³ of alkali neutralises 30 cm³ of acid.
Wear goggles throughout; pour at bench level; wash any splash off at once with plenty of water.Right first time
Hydrochloric acid, 2.0 mol/dm³ (irritant)
Irritates the eyes and skin
Wear goggles; wash any splash off with plenty of water.Right first time
Polystyrene cup tipping over
Corrosive solution spilt onto skin and the bench
Stand the cup inside a 250 cm³ beaker so it cannot tip.Right first time
Glass thermometer used to stir
Cuts from broken glass
Stir gently, do not lean on the thermometer, and report any breakage to the teacher.Right first time
2 Apparatus
✓Eye protection (goggles) Protects the eyes from corrosive splashes.
✓Dilute hydrochloric acid, 2.0 mol/dm³ (irritant) The acid: 30 cm³ for each run.
✓Sodium hydroxide solution, 2.0 mol/dm³ (corrosive) The alkali, added 5 cm³ at a time.
✓Expanded polystyrene cup and lid with a hole Insulated container for the reaction.
✓250 cm³ glass beaker Holds the cup steady (or is the container, if you choose).
✓Measuring cylinders: 50 cm³ and 10 cm³ (resolution 1 cm³ and 0.2 cm³) Measure the acid and the portions of alkali.
✓Thermometer: digital, or glass 0–110 °C (resolution 0.1 °C (digital), 1 °C divisions (glass)) Measures the temperature of the mixture; also used to stir.
3 Method: your choices
Check the thermometer: DoneA thermometer that reads high (or low) adds the same error to every temperature.
Let both solutions reach room temperature: DoneThe temperature change only comes from the reaction if the acid and the alkali start at the same temperature.
Put on eye protectionSafety: DoneSodium hydroxide solution is corrosive: a splash in the eye can cause serious, permanent damage.
Choose what to do the reaction in: Polystyrene cup with a lidPolystyrene is a good thermal insulator and has almost no heat capacity, so the highest temperatures are close (about 85–95 %) to what the reaction could give.
Stand the cup in a beakerSafety: DoneA polystyrene cup is light and tips over easily, spilling corrosive solution.
Choose a measuring cylinder for the 5 cm³ portions: 10 cm³ measuring cylinder (0.2 cm³ divisions)Each portion is 5.0 cm³ to within about 0.1 cm³, so the volumes on your graph are right.
Fit the lid after each addition: DoneWarm air and water vapour escape from an open top, carrying energy away.
Choose a thermometer: Digital thermometer (resolution 0.1 °C)Reads to 0.1 °C and responds in a few seconds.
Stir after each addition: DoneUntil it is stirred, the cold alkali and the warm mixture are in layers, and the thermometer reads only the part around it.
Wait for the highest temperature: DoneThe thermometer needs a few seconds to catch up with the mixture.
4 Results
18 of 18 readings taken.
Highest temperature after each addition · 30 cm³ of hydrochloric acid in a polystyrene cup; sodium hydroxide added 5 cm³ at a time. Means to 2 decimal places.
Volume of sodium hydroxide added in cm³
Highest temperature, run 1 in °C
Highest temperature, run 2 in °C
Mean highest temperature in °C
0
22.8
22.2
22.50
5
26.4
26.3
26.35
10
29.5
29.3
29.40
15
31.0
31.0
31.00
20
30.5 (anomalous, left out)
32.9
32.90
25
33.9
33.8
33.85
30
35.0
34.8
34.90
35
34.1
34.4
34.25
40
33.1
33.5
33.30
0.0 Ringed: the anomaly, left out of the mean.
Anomaly: Highest temperature, 20 cm³ added, run 1, left out of the mean. Likely cause: the solution had not been stirred: the cold alkali had not mixed in when the thermometer was read.
5 Graph
Temperature against volume of sodium hydroxide
6 Analysis
Shape of the graph
Describe the shape of your graph.
The temperature rises steadily, then falls once all the acid has reacted.Right first time
Volume where the lines cross
the volume of sodium hydroxide that exactly neutralises the 30 cm³ of acid
26.4 cm³Right first time
Temperature where the lines cross
the highest temperature the mixture would reach if no energy were lost
35.5 °CRight first time
Temperature rise
temperature rise = temperature where the lines cross − starting temperature
Use your graph to work out the greatest temperature rise in the reaction.
13.0 °CRight first time
7 Conclusion and evaluation
Quantity
Your value
Accepted value
Volume that neutralises the acid (where your lines cross; reference from the 2.0 mol/dm³ labels)
26.4 cm³
30.0 cm³
Temperature rise if no energy were lost (reference for 2.0 mol/dm³ solutions)
13.03 °C
13.39 °C
Conclusion
What do your results show?
The temperature rose while the acid reacted, then fell once it had all reacted. The lines of best fit cross at about 26 cm³: about 26 cm³ of sodium hydroxide neutralised the 30 cm³ of acid.Right first time
Neutralisation is exothermic. Energy is released with each portion until all the acid has reacted; the extra alkali after that only cools the mixture. The end point is where the two lines cross.
Sources of error
Energy transferred to the surroundings through the sides and top of the container: systematic or random?
SystematicRight first time
Every highest temperature is lower than the reaction could give, and the temperature falls faster after the end point.
Not stirring, or reading before the temperature stopped rising: systematic or random?
RandomRight first time
Some readings are lower than they should be, by different amounts, so the points scatter about the lines.
The solutions starting at different temperatures: systematic or random?
RandomRight first time
A cold alkali lowers the temperature of the mixture, so the two runs give different highest temperatures.
The rising points curve over (each 5 cm³ warms a bigger volume of solution, and a hotter mixture loses energy faster): systematic or random?
SystematicRight first time
The two straight lines cross a little before the true end point (about 27 cm³ instead of 30 cm³) and a little above the highest reading.
Resolution of the thermometer: systematic or random?
RandomRight first time
A glass thermometer with 1 °C divisions can only be read to the nearest 0.5 °C, so small changes are lost.
Measuring the 5 cm³ portions in a large measuring cylinder: systematic or random?
RandomRight first time
The portions are not all 5 cm³, so the volumes on the graph are wrong and the end point moves.
A thermometer that reads high (a zero error): systematic or random?
SystematicRight first time
Every temperature is too high by the same amount; temperature changes are not affected, because the error cancels.
Improvement
Which change would most improve your results?
Stir after every addition and wait until the reading stops changing before recording it.Right first time
Repeatable or reproducible
You repeat the whole run with fresh acid and your highest temperatures agree with the first run to within 0.3 °C. This shows your results are…
RepeatableRight first time
Repeatable: the same person, method and equipment give similar results.
Another group uses a temperature probe and data logger and finds the lines cross at almost the same volume. This shows the result is…
ReproducibleRight first time
Reproducible: a different person or a different method gives similar results.
8 Make safe and clear up
Pour the neutral salt solution down the sink with plenty of water
Rinse the thermometer and the measuring cylinders with water
Put the used cup in the bin and wipe up any spills
Put the lids back on the stock bottles, then take off your goggles last
9 Exam questions on your data
On your own readings, self-marked against the mark scheme, with error carried forward where it applies. Total 30/30.
01.1[1 mark]
A student added sodium hydroxide solution 5 cm³ at a time to 30 cm³ of hydrochloric acid in a polystyrene cup and recorded the highest temperature after each addition.
Give the independent variable in this investigation.
Your answer
The volume of sodium hydroxide solution added
1/1 self-marked
Volume of sodium hydroxide (solution) added; do not accept "amount"
Self-marked: 1 of 1 mark. This is your own judgement against the mark scheme.
Model answer: The volume of sodium hydroxide solution added.
01.2[1 mark]
A student added different volumes of sodium hydroxide solution to dilute hydrochloric acid in a polystyrene cup and measured the highest temperature of each mixture.
Give the dependent variable in this investigation.
Your answer
The highest temperature of the mixture
1/1 self-marked
(Highest / maximum) temperature (of the mixture); allow change in temperature
Self-marked: 1 of 1 mark. This is your own judgement against the mark scheme.
Model answer: The highest temperature of the mixture.
01.3[2 marks]
You did the reaction in a polystyrene cup. Another student used a glass beaker.
Explain why a polystyrene cup gives better results than a glass beaker.
Your answer
Polystyrene is a better thermal insulator than glass, so less energy is transferred from the mixture to the surroundings.
2/2 self-marked
Polystyrene is a better (thermal) insulator; allow glass is a better conductor
(So) less energy is transferred to the surroundings; allow reduces energy (heat) loss
Self-marked: 2 of 2 marks. This is your own judgement against the mark scheme.
Model answer: Polystyrene is a better thermal insulator than glass, so less energy is transferred to the surroundings.
01.4[1 mark]
The sodium hydroxide solution is labelled CORROSIVE.
Explain why the student must wear eye protection.
Your answer
Sodium hydroxide could splash into the eyes and cause serious eye damage or even blindness.
1/1 self-marked
Splashes could damage the eyes (cause blindness / burn the eyes); ignore "it is dangerous"
Self-marked: 1 of 1 mark. This is your own judgement against the mark scheme.
Model answer: A splash of corrosive sodium hydroxide in the eye could cause serious eye damage or blindness.
01.5[1 mark]
A digital thermometer shows 29.3 °C.
What is the resolution of the thermometer?
Tick (✓) one box.
✓ 0.1 °C (your choice)
0.3 °C
1 °C
29.3 °C
Your answer
0.1 °C
1/1
0.1 °C
Full marks. Clear and precise.
Model answer: 0.1 °C: the last digit on the display changes in steps of 0.1 °C.
01.6[1 mark]
A student added sodium hydroxide solution to hydrochloric acid in a polystyrene cup and measured the temperature of the mixture as it was added.
How do the results show that the reaction between hydrochloric acid and sodium hydroxide is exothermic?
Your answer
The temperature increased when the sodium hydroxide was added.
1/1 self-marked
The temperature increases; allow energy (heat) transferred to the surroundings; ignore "because it is exothermic"
Self-marked: 1 of 1 mark. This is your own judgement against the mark scheme.
Model answer: The temperature of the mixture increased as the sodium hydroxide was added.
02.1[1 mark]
Table 1 shows the results of your first run.
Which result is anomalous?
Select one row.
Table 1
Total volume of sodium hydroxide added in cm³
Maximum temperature in °C
0
22.8
5
26.4
10
29.5
15
31.0
20
30.5
25
33.9
30
35.0
35
34.1
40
33.1
Your answer
the reading at 20 cm³
1/1
The reading at 20 cm³: lower than the smooth rise through the readings either side
Full marks. Your answer meets all the points for this question. Look for the reading that breaks the smooth rise: 20 cm³ (30.5 °C) is lower than the readings either side suggest.
Model answer: The reading at 20 cm³. It is lower than the pattern of the readings either side.
02.2[1 mark]
Table 1 shows the results of your first run.
Table 1
Total volume of sodium hydroxide added in cm³
Maximum temperature in °C
0
22.8
5
26.4
10
29.5
15
31.0
20
30.5
25
33.9
30
35.0
35
34.1
40
33.1
Suggest one reason for the anomalous result at 20 cm³.
Your answer
The student did not stir the solution, so the temperature was measured too soon.
1/1 self-marked
Did not stir (the solution enough); allow measured the temperature too soon (before it stopped rising / before the highest temperature)
Self-marked: 1 of 1 mark. This is your own judgement against the mark scheme.
Model answer: The solution was not stirred, so the temperature was measured before it had reached its highest value.
02.3[2 marks]
Four groups measured the highest temperature after adding 30 cm³ of sodium hydroxide.
Table 2
Group
Highest temperature in °C
A
35.2
B
34.8
C
35.0
D
34.6
Calculate the mean highest temperature.
Your answer
34.9
Working: (35.2 + 34.8 + 35.0 + 34.6) ÷ 4 = 139.6 ÷ 4
mean = 34.9 °C
2/2
(35.2 + 34.8 + 35.0 + 34.6) ÷ 4
= 34.9 (°C)
Full marks. Your answer meets all the points for this question.
Model answer: (35.2 + 34.8 + 35.0 + 34.6) ÷ 4 = 139.6 ÷ 4
mean = 34.9 °C
02.4[1 mark]
Four groups measured the highest temperature after adding 30 cm³ of sodium hydroxide.
Table 2
Group
Highest temperature in °C
A
35.2
B
34.8
C
35.0
D
34.6
The mean is 34.9 °C. Give the uncertainty in the mean.
Your answer
0.3
1/1
± 0.3 °C: the values are at most 0.3 °C either side of the mean (35.2 − 34.6 = 0.6; half of 0.6)
Full marks. Clear and precise.
Model answer: ± 0.3 °C (the readings are 34.6–35.2 °C, at most 0.3 °C either side of the mean)
02.5[1 mark]
A student plotted mean maximum temperature (y-axis) against the volume of sodium hydroxide added (x-axis).
How should the student draw the lines of best fit to find the volume that neutralises the acid?
Tick (✓) one box.
One straight line of best fit through all the points.
A smooth curve through the highest point.
✓ Two straight lines: one through the rising points and one through the falling points, extended until they cross. (your choice)
Join each point to the next with a ruler.
Your answer
Two straight lines: one through the rising points and one through the falling points, extended until they cross.
1/1
Two straight lines: one through the rising points and one through the falling points, extended until they cross.
Full marks. Your answer meets all the points for this question.
Model answer: Two straight lines, one through the rising points and one through the falling points, extended until they cross.
02.6[2 marks]
Table 3 shows your mean results. Your two lines of best fit cross at 35.5 °C.
Table 3
Total volume of sodium hydroxide added in cm³
Mean maximum temperature in °C
0
22.50
5
26.35
10
29.40
15
31.00
20
32.90
25
33.85
30
34.90
35
34.25
40
33.30
Calculate the temperature change at neutralisation.
Your answer
13
Working: 35.5 − 22.5
= 13 °C
2/2
35.5 − 22.5 (crossing temperature − starting temperature)
= 13 (°C)
Full marks. Your answer meets all the points for this question.
Model answer: 35.5 − 22.5
= 13 °C
02.7[4 marks]
Your graph shows that 26.4 cm³ of sodium hydroxide solution neutralised 30.0 cm³ of hydrochloric acid.
The concentration of the hydrochloric acid was 2.00 mol/dm³.
HCl(aq) + NaOH(aq) → NaCl(aq) + H₂O(l)
Calculate the concentration of the sodium hydroxide solution in mol/dm³.
The temperature rose and then fell. Your lines of best fit cross at about 26.4 cm³ of sodium hydroxide.
Explain the shape of the graph.
Your answer
The temperature rises because the reaction is exothermic. The crossing of the lines estimates that the acid has been neutralised at about 26.4 cm³. After neutralisation there is no more reaction and no more energy is released. The sodium hydroxide is then in excess, so the extra cooler alkali and energy transferred to the surroundings make the temperature fall.
3/3 self-marked
The temperature rises because the reaction is exothermic (releases energy)
At the estimated crossing, about 26.4 cm³, all the acid has reacted (been neutralised / used up)
After that there is no more reaction, so no more energy is released
The sodium hydroxide is in excess: the extra (cooler) alkali, and energy transferred to the surroundings, lower the temperature
Self-marked: 3 of 3 marks. This is your own judgement against the mark scheme.
Model answer: The temperature rises because the reaction is exothermic. The crossing of the lines estimates that the acid has been neutralised at about 26.4 cm³. After neutralisation there is no more reaction and no more energy is released. The sodium hydroxide is then in excess: the extra cooler alkali and energy transferred to the surroundings make the temperature fall.
03.2[1 mark]
Another student’s points were scattered above and below their lines of best fit.
What type of error does this show?
Tick (✓) one box.
✓ Random error (your choice)
Systematic error
Zero error
No error: the results are accurate
Your answer
Random error
1/1
Random error
Full marks. That is exactly what the mark scheme is looking for.
Model answer: Random error: it scatters the points either side of the line.
03.3[1 mark]
In your two runs the highest temperature after 0 cm³ was 22.8 °C and 22.2 °C.
Suggest one reason why the two temperatures are different.
Your answer
The starting temperature of the solutions was different in the two runs.
1/1 self-marked
Starting temperature may be different; or inconsistent stirring; allow inconsistent use of a lid; ignore room temperature
Self-marked: 1 of 1 mark. This is your own judgement against the mark scheme.
Model answer: The starting temperature of the solutions was different in the two runs (or the solution was stirred differently).
03.4[6 marks]
A student investigated how the highest temperature reached depends on the mass of sodium carbonate added to dilute hydrochloric acid.
Describe a method the student could use.
Your answer
1. Measure 25 cm³ of dilute hydrochloric acid with a measuring cylinder.
2. Pour the acid into a polystyrene cup standing in a beaker.
3. Measure the starting temperature of the acid with a thermometer.
4. Weigh 0.5 g of sodium carbonate on a balance.
5. Add the sodium carbonate to the acid, put on the lid and stir.
6. Record the highest temperature reached.
7. Repeat with different masses of sodium carbonate (1.0 g, 1.5 g, 2.0 g, 2.5 g), using fresh acid at the same starting temperature each time.
8. Keep the volume and concentration of the acid the same, and repeat each mass to calculate a mean.
6/6 self-marked
Measure a volume of (hydrochloric) acid with a measuring cylinder
Pour it into a suitable container, eg a polystyrene cup (with a lid)
Measure the initial temperature
Add a known mass of sodium carbonate measured with a balance
Stir
Measure the highest temperature reached
Repeat with different masses
Use the same volume / concentration of acid and the same starting temperature
Self-marked: Level 3, 6 of 6 marks. You ticked 8 of 8 indicative points. This is your own judgement against the mark scheme.
Model answer: 1. Measure 25 cm³ of dilute hydrochloric acid with a measuring cylinder.
2. Pour the acid into a polystyrene cup standing in a beaker.
3. Measure the starting temperature of the acid with a thermometer.
4. Weigh 0.5 g of sodium carbonate on a balance.
5. Add the sodium carbonate to the acid, put on the lid and stir.
6. Record the highest temperature reached.
7. Repeat with different masses of sodium carbonate (1.0 g, 1.5 g, 2.0 g, 2.5 g), using fresh acid at the same starting temperature each time.
8. Keep the volume and concentration of the acid the same, and repeat each mass to calculate a mean.
Unseen data: the same skills, new apparatus
01[3 marks]
A student adds 1.0 g of zinc powder to 25 cm³ of copper sulfate solution in a polystyrene cup and records the highest temperature. They do this five times. In one repeat they forgot to stir.
Highest temperature
Repeat
Highest temperature in °C
1
37.7
2
37.9
3
35.5
4
38.2
5
37.8
Calculate the mean highest temperature. Give your answer to 1 decimal place.
Leave out 35.5 °C, the repeat that was not stirred.
(37.7 + 37.8 + 37.9 + 38.2) ÷ 4.
The mean, in °C, to 1 decimal place.
Full marks. Clear and precise.
Model answer: Leave out 35.5 °C (not stirred).
Mean = (37.7 + 37.8 + 37.9 + 38.2) ÷ 4 = 37.9 °C.
02[2 marks]
Citric acid solution reacts with sodium hydrogencarbonate and the temperature falls. A student does the reaction in a polystyrene cup and then in a metal can, starting at 18.4 °C both times. The lowest temperature is 10.6 °C in the cup but only 14.4 °C in the can.
Which TWO statements explain why the cup gives the better result? Tick (✓) two boxes.
✓ Polystyrene is a better thermal insulator than metal. (your choice)
✓ Less energy is transferred from the surroundings into the mixture in the cup, so its temperature falls further. (your choice)
The reaction is faster in polystyrene.
Polystyrene absorbs the cold, so the reading is lower.
More citric acid reacts in the cup than in the can.
Your answer
Polystyrene is a better thermal insulator than metal.; Less energy is transferred from the surroundings into the mixture in the cup, so its temperature falls further.
2/2
Polystyrene is a better thermal insulator than metal.
Less energy is transferred from the surroundings into the mixture in the cup, so its temperature falls further.
Full marks. Your answer meets all the points for this question.
Model answer: Polystyrene is a better thermal insulator. In the metal can, energy is transferred from the warmer surroundings into the cold mixture faster, so its temperature does not fall as far. The same amount reacts in both.
03[2 marks]
A student adds zinc powder 0.2 g at a time to 25 cm³ of copper sulfate solution and records the highest temperature after each addition. The temperature rises until 1.0 g of zinc has been added, then falls slowly.
Which TWO statements explain the shape of the graph? Tick (✓) two boxes.
✓ The temperature rises because the reaction is exothermic: each portion of zinc that reacts releases energy. (your choice)
✓ After 1.0 g the copper sulfate has all reacted, so the extra zinc is in excess and releases no more energy. (your choice)
After 1.0 g the zinc has all been used up.
After 1.0 g the reaction becomes endothermic.
The temperature falls because the reaction gets faster.
Your answer
The temperature rises because the reaction is exothermic: each portion of zinc that reacts releases energy.; After 1.0 g the copper sulfate has all reacted, so the extra zinc is in excess and releases no more energy.
2/2
The temperature rises because the reaction is exothermic: each portion of zinc that reacts releases energy.
After 1.0 g the copper sulfate has all reacted, so the extra zinc is in excess and releases no more energy.
Full marks. Clear and precise.
Model answer: Each portion of zinc reacts and releases energy (exothermic), until the copper sulfate is used up at 1.0 g. After that the zinc is in excess: no more reaction, and the mixture loses energy to the surroundings.