A blank nine-step write-up with the correct table headings. Print it for a real lesson and fill it in by hand. See the specimen lab book
Blank write-up: Temperature changes
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Study Hack Lab
RP 4 · Chemistry
Temperature changes
Write-up template
Name
Date
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
Class and teacher
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
A blank write-up for use in a real lesson. The headings follow the AQA required practical; the readings are yours to take. 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)
Dependent (you measure)
Control (you keep the same)
Prediction
When sodium hydroxide solution neutralises hydrochloric acid, what will happen to the temperature of the mixture?
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?
The acid and the alkali have the same concentration. After how much sodium hydroxide will the temperature be highest?
Risk assessment
Hazard
Harm it could cause
Control
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
Write numbered steps someone else could follow. Say what you measure, with which instrument, and how you keep it a fair test.
4 Results
The table is drawn before you measure. Record each reading to the resolution of the instrument, then work out the mean of your repeats, leaving out any anomaly.
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
5
10
15
20
25
30
35
40
Anomalies
Ring any anomalous result. Say what probably went wrong and whether you repeated it.
5 Graph
Temperature against volume of sodium hydroxide · Choose your axes: the independent variable goes on the x-axis. Label each axis with the quantity and unit.
6 Analysis
Temperature against volume of sodium hydroxide
Answer
Temperature rise
temperature rise = temperature where the lines cross − starting temperature
Answer
7 Conclusion and evaluation
Conclusion
Conclusion: what do your results show? Use your own numbers.
Sources of error
For each, say whether it is systematic or random, and how it affected your results.
Energy transferred to the surroundings through the sides and top of the container
Not stirring, or reading before the temperature stopped rising
The solutions starting at different temperatures
The rising points curve over (each 5 cm³ warms a bigger volume of solution, and a hotter mixture loses energy faster)
Resolution of the thermometer
Measuring the 5 cm³ portions in a large measuring cylinder
A thermometer that reads high (a zero error)
Improvement
How could you improve the method? Say why it would help.
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