AQA GCSE Combined Science: Trilogy Chemistry Paper 1 (Foundation), 2024: Question 6

9 marks · Standard Demand difficulty · Short Answer

Interpret a graph of copper production, explain why a copper-zinc alloy is harder than pure copper, and calculate the mass of copper in an alloy sample from percentage by mass.

Practise this question

Question

The question page is headed 'Copper is a useful metal' and contains three parts labelled 06.1, 06.2 and 06.3. Part 06.1 shows a line graph titled Figure 11 of mass of copper produced each year between 1900 and 2010, with year on the x-axis and mass of copper produced each year in 10^9 kilograms on the y-axis; the curve rises slowly at first and then steeply, and students are asked to give two conclusions from the graph for 2 marks. Part 06.2 states that mixtures of copper and zinc are heated to produce alloys and shows Figure 12 with particle diagrams: pure copper as equal-sized atoms in regular layers, and an alloy of copper and zinc with different-sized atoms labelled zinc atom and copper atom; students must explain why the alloy is harder than pure copper for 3 marks. Part 06.3 gives a 5.25 g sample of a copper-zinc alloy containing 13.5% zinc by mass and asks students to calculate the mass of copper to 3 significant figures, worth 4 marks.
Question text

06 Copper is a useful metal.

06.1 Figure 11 shows the mass of copper produced between 1900 and 2010.

Figure 11

Give two conclusions that can be made from Figure 11.

[2 marks]

Mixtures of copper and zinc are heated to produce alloys.

06.2 Figure 12 represents the structures of pure copper and of an

alloy of copper and zinc.

Figure 12

Explain why the alloy of copper and zinc is harder than pure copper.

Use Figure 12.

[3 marks]

06.3 A 5.25 g sample of an alloy of copper and zinc contains 13.5% zinc by mass.

Calculate the mass of copper in the 5.25 g sample.

Give your answer to 3 significant figures.

[4 marks]

Mass of copper (3 significant figures) = g

Mark scheme

Show the mark scheme The mark scheme for Question 6 is presented in tables for parts 06.1 to 06.3 with columns for answers, extra information, mark and AO/specification reference. For 06.1, any two valid graph conclusions gain marks, including that copper production increased from 1900 to 2010, increased only slightly before about 1930, increased rapidly after about 1930, was highest in 2010, lowest in 1900, and that the increase was not linear. For 06.2, marks are for stating that the atoms in the alloy are different sizes, this distorts the layers, and therefore the layers or atoms cannot easily slide over each other. For 06.3, marks are for finding copper as 100 minus 13.5 equals 86.5 percent, then calculating 86.5/100 multiplied by 5.25 to get 4.54125 g and rounding to 4.54 g, with an alternative method via zinc mass also accepted; the total for Question 6 is 9 marks.

Question 6

AO /

Question Answers Extra information Mark

Spec. Ref.

06.1 any two from: 2 AO3

• mass of copper produced 5.2.2.7

increased (from 1900 to 2010)

• before 1930 the mass of allow a value in the range 1925

copper produced increased to 1930

slightly

• after 1930 the mass of copper allow a value in the range 1925

produced increased rapidly to 1930

• the highest mass of copper allow the highest mass of

was produced in 2010 copper produced was 15.8

(× 109 kilograms)

• the lowest mass of copper allow the lowest mass of copper

was produced in 1900 produced was 0.2 (× 109

kilograms)

• the increase in the mass of

copper produced was not

linear

AO /

Spec. Ref.

06.2 (alloy of copper and zinc is 1 AO2

harder because) the atoms are 5.2.2.7

different sizes

(so the) layers are distorted 1

(so the) layers cannot easily allow (so the) atoms cannot 1

slide – slide over each other – –

AO /

Spec. Ref.

06.3 (% copper = 100 – 13.5 =) 1 AO2

86.5 (%) 5.2.2.7

86.5 allow correct use of an 1

(mass of copper =) × 5.25

100 incorrectly determined

percentage of copper

= 4.54125 (g) 1

= 4.54 (g) 1

allow an answer correctly 19

rounded to 3 significant figures

from an incorrect calculation

which uses the values in the

question

OR

13.5

(mass of zinc =) × 5.25 (1)

= 0.70875 (g) (1)

(mass of copper = 5.25 –

0.70875)

= 4.54125 (g) (1) allow correct use of an

incorrectly determined mass of

zinc

= 4.54 (g) (1) allow an answer correctly

rounded to 3 significant figures

from an incorrect calculation

which uses the values in the

question

Total Question 6 9

How to answer it

Copper, alloys and percentage composition

What this question tests

Skills: reading a graph, making conclusions from data, explaining alloy properties using particle models, and calculating percentage mass in a mixture.

Knowledge: copper production trends, why alloys are harder than pure metals, and how to use percentages to find mass.

Exam focus: give precise, data-based conclusions; explain using different atom sizes → distorted layers → difficult to slide; show clear calculation steps and final units.

Question 6.1 — Conclusions from Figure 11

Give two conclusions that can be made from the graph.

✅ Correct answers

  • The mass of copper produced increased from 1900 to 2010.
  • Before about 1930, the mass increased only slightly.
  • After about 1930, the mass increased rapidly.
  • The highest mass was produced in 2010.
  • The lowest mass was produced in 1900.
  • The increase was not linear.
Any two of these gain the 2 marks.

💡 Key knowledge

  • A graph conclusion should describe the overall trend or a clear feature of the data.
  • You do not need exact values unless asked.
  • Reading the curve: it starts low, rises slowly, then rises more steeply.

🧠 Exam technique

  • Use words like increased, decreased, rapidly, slightly, highest, lowest.
  • Base your answer on what the curve shows, not on reasons for the trend.
  • For 2 marks, write two separate statements.

❌ Common errors

  • Saying “copper is useful” — that is not a conclusion from the graph.
  • Giving a reason, e.g. “more demand” — no marks for speculation.
  • Saying “the graph goes up” without any detail may be too vague.

📐 How to write a full-mark response

  1. The mass of copper produced increased from 1900 to 2010.
  2. After about 1930, it increased rapidly / the increase was not linear.

Question 6.2 — Why the alloy is harder

Explain why the alloy of copper and zinc is harder than pure copper. Use Figure 12.

✅ Correct answers

  • The atoms are different sizes.
  • This distorts the layers in the metal structure.
  • The layers cannot easily slide over each other.
  • Therefore the alloy is harder than pure copper.
Full marks need the idea chain: different sizes → distorted layers → difficult to slide.

💡 Key knowledge

  • Pure metals have regular layers of identical atoms.
  • Alloys contain different atoms, so the regular pattern is disrupted.
  • Hardness increases because the layers are less able to move.

🧠 Exam technique

  • Use the figure: copper and zinc atoms are shown as different-sized circles.
  • Describe what this causes in the structure, then link to hardness.
  • A 3-mark answer usually needs three linked points.

❌ Common errors

  • Saying “alloys are harder because they are mixed together” — too vague.
  • Talking only about bonding without mentioning layers or movement.
  • Not using the figure at all.

✅ Example 3-mark response

The zinc atoms are a different size from the copper atoms, so the layers in the structure are distorted. This means the layers cannot easily slide over each other, so the alloy is harder than pure copper.

Question 6.3 — Calculating the mass of copper

A 5.25 g sample of alloy contains 13.5% zinc by mass. Calculate the mass of copper to 3 significant figures.

📐 Step-by-step calculation

  1. Find the percentage of copper:
    100 − 13.5 = 86.5%
  2. Convert to a fraction:
    86.5 / 100 = 0.865
  3. Multiply by the total mass:
    0.865 × 5.25 = 4.54125 g
  4. Round to 3 significant figures:
    4.54 g

✅ Correct answer

Mass of copper = 4.54 g

1 mark for finding 86.5% copper, 1 mark for using the percentage correctly, and marks for the calculation and correct 3 s.f. answer.

🧠 Exam technique

  • Always identify the part you are calculating first.
  • Keep units with the final answer: g.
  • Check that your final answer is sensible: it should be less than 5.25 g because some of the sample is zinc.
  • Show working clearly to gain method marks even if a small arithmetic error happens.

❌ Common calculation traps

  • Using 13.5% instead of 86.5% for copper.
  • Forgetting to divide by 100 when turning a percentage into a decimal.
  • Rounding too early.
  • Giving the answer without units.
  • Not rounding to 3 significant figures.

💡 Why this calculation scores well

  • The mark scheme allows either method: find copper directly, or find zinc first and subtract from 5.25 g.
  • What matters most is correct use of percentage, mass, and final rounding.

Quick recall summary

🔑 Must-remember facts

  • Graphs can show trends such as increasing, rapid increase, or non-linear change.
  • Alloys are harder because different-sized atoms distort layers.
  • Hardness increases when layers cannot slide easily.
  • Percentage by mass = part ÷ whole × 100.

🎯 How to get full marks here

  • For data questions: make two separate conclusions.
  • For explanation questions: give cause → effect → result.
  • For maths questions: show steps, use units, and round correctly.

Topics

Chemistry · C2: Bonding, Structure and the Properties of Matter · C3: Quantitative Chemistry

Question and mark scheme from the AQA GCSE Combined Science: Trilogy examination, Chemistry Paper 1 (Foundation), 2024. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.