AQA GCSE Physics Physics Paper 1 (Foundation), June 2022: Question 5

8 marks · Standard Demand difficulty · Short Answer

Investigate the specific latent heat of vaporisation of water including measuring mass, identifying variables, safety precautions, calculating latent heat, and identifying experimental errors.

Practise this question

Question

Figure 6 shows an experimental setup with a power supply connected to an immersion heater placed inside a beaker of water. The question contains five parts (05.1 to 05.5) asking students to identify measuring instruments, variable types, safety methods for handling hot beakers, calculate specific latent heat given energy and mass values, and identify sources of thermal energy loss.
Question text

05 A student determined the specific latent heat of vaporisation of water.

Figure 6 shows some of the equipment used.

Figure 6

05.1 The student measured a mass of water and put it into the beaker.

What measuring instrument should the student have used to measure the mass of the

water?

[1 mark]

Tick ( ) one box.

balance

joulemeter

newtonmeter

thermometer 15

05.2 The power output of the heater stayed the same throughout the experiment.

What type of variable was the power output of the heater?

[1 mark]

Tick ( ) one box.

Categoric variable

Control variable

Dependent variable

Independent variable

05.3 The student turned on the heater and heated the water until it reached boiling point.

The student continued to heat the water so that it boiled for several minutes.

The mass of the water remaining in the beaker was measured again.

Give one way the beaker of boiling water could be moved safely to measure its

new mass.

[1 mark]

05.4 The mass of water that turned into steam was 0.0090 kg.

The heater transferred 25 200 J of energy to the water to turn it into steam.

Calculate the specific latent heat of vaporisation of water given by the student’s data.

Use the Physics Equations Sheet.

Choose the unit from the box.

[4 marks]

J kg J/kg

Specific latent heat of vaporisation = Unit

05.5 What was a source of error in the student’s experiment?

[1 mark]

Tick ( ) one box.

The transfer of thermal energy from the heater to the water

The transfer of thermal energy from the surroundings to the water

The transfer of thermal energy from the water to the heater

The transfer of thermal energy from the water to the surroundings

Mark scheme

Show the mark scheme The mark scheme provides answers for questions 05.1 through 05.5, allocating 1 mark each for balance, control variable, safe handling methods like tongs or gloves, 4 marks for the calculation of latent heat resulting in 2 800 000 J/kg, and 1 mark for identifying thermal energy transfer from water to the surroundings as an error.

Question 5

AO /

Question Answers Extra information Mark

Spec. Ref.

05.1 balance 1 AO3

4.3.2.3

AO /

Spec. Ref.

05.2 control variable 1 AO3

4.3.2.3

AO /

Spec. Ref.

05.3 use tongs / gloves allow other sensible methods of 1 AO2

or avoiding contact with hot beaker 4.3.2.3

use a heatproof mat eg using a cloth

allow wait for the beaker (and

hot water) to cool down

AO /

Spec. Ref.

05.4 25 200 = 0.0090 L 1 AO2

25 200

L = 1 AO2

0.0090

L = 2 800 000

or 1 AO2

L = 2.8 × 106

J/kg 1 AO1

– HYSICS – –

4.1.1.4

AO / 15

Spec. Ref.

05.5 the transfer of thermal energy 1 AO3

from the water to the 4.3.2.3

surroundings 4.1.2.1

Total Question 5 8

How to answer it

Determining Specific Latent Heat of Vapourisation

What this question tests

This question assesses your understanding of thermal physics practical skills, specifically internal energy, specific latent heat of vapourisation, identifying variables, laboratory safety, energy calculations, and sources of thermal energy error.

Part 05.1 [1 mark]

Measuring Instrument for Mass

✅ Correct Answer

balance (ticked)

Awarded 1 mark for selecting the correct piece of measuring apparatus (AO3).

💡 Key Knowledge

  • Mass is measured in kilograms (kg) or grams (g) using a digital balance or scales.
  • A joulemeter measures energy, a newtonmeter measures force/weight, and a thermometer measures temperature.
Part 05.2 [1 mark]

Identifying Variables

✅ Correct Answer

control variable (ticked)

Awarded 1 mark for correctly identifying that keeping power output the same makes it a control variable (AO3).

💡 Key Knowledge

  • Control variable: A variable that is kept constant so it doesn't affect the results of the experiment.
  • If power changed randomly, energy transferred wouldn't be directly proportional to time and mass evaporated.
Part 05.3 [1 mark]

Safe Handling in the Lab

✅ Correct Answer

Use tongs, gloves, or a heatproof mat (or allow the beaker to cool down).

Awarded 1 mark for a sensible safety precaution avoiding direct contact with boiling water/glass (AO2).

❌ Common Errors

Writing vague statements like "be careful" or "don't touch it" without stating how safety is achieved (e.g., using heat-resistant gloves or tongs).

Part 05.4 [4 marks]

Calculating Specific Latent Heat

📐 Step-by-Step Calculation

  1. Recall formula: Energy = mass × specific latent heat ( E = m × L ) or rearrangement L = E / m
  2. Substitute values: L = 25200 / 0.0090
  3. Calculate value: L = 2 800 000 (or standard form 2.8 × 10⁶ )
  4. Select correct unit: J/kg
Marks: 1 for substitution, 1 for correct calculation, 1 for correct numerical answer, 1 for unit J/kg (AO1/AO2).

❌ Common Calculation Traps

  • Failing to select the correct unit box ( J/kg ). Do not write J/g or just J .
  • Incorrectly transposing values into the equation (e.g., multiplying mass by energy instead of dividing).
Part 05.5 [1 mark]

Sources of Thermal Error

✅ Correct Answer

The transfer of thermal energy from the water to the surroundings (ticked)

Awarded 1 mark for identifying heat loss to the surrounding environment as a systematic error (AO3).

🧠 Exam Technique

Always look out for energy dissipation in thermal practicals. Because the beaker isn't insulated, some thermal energy escapes into the air rather than boiling the water, leading to less mass changing to steam than expected for the energy supplied.

Topics

Physics · Required Practicals · Required Practicals · P3: Particle Model of Matter

Question and mark scheme from the AQA GCSE Physics examination, Physics Paper 1 (Foundation), June 2022. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.