AQA GCSE Chemistry Chemistry Paper 1 (Foundation), June 2024: Question 8
10 marks · Standard Demand difficulty · Short Answer
Describe the preparation of a salt from copper carbonate and sulfuric acid, calculate the actual yield from percentage yield, and explain why certain metals cannot be used directly with acids.
Practise this questionQuestion
Question text
08 A student produced a salt by reacting copper carbonate with sulfuric acid.
This is the method used.
1. Measure 50 cm3 of sulfuric acid into a beaker.
2. Add copper carbonate powder.
3. Stir the mixture.
4. Repeat steps 2 and 3 until copper carbonate is in excess.
5. Filter the mixture.
6. Warm the filtrate gently until crystals start to appear.
7. Leave the solution to cool and crystallise.
08.1 Complete the word equation for the reaction.
[2 marks]
copper sulfuric carbon
+ → + +
carbonate acid dioxide
08.2 Give one observation the student could make during Step 4 which shows that the
copper carbonate is in excess.
[1 mark]
08.3 Give one reason for filtering the mixture in Step 5.
[1 mark]
08.4 Name the equipment that can be used to warm the filtrate gently in Step 6.
[1 mark]
*0348.*5 The maximum theoretical mass of the salt that could be produced using 50 cm3 of the
sulfuric acid is 12.5 g.
The percentage yield of the salt is 92.8%.
Calculate the mass of salt actually produced.
Use the equation:
mass of salt actually produced
% yield = ×100
maximum theoretical mass of salt that could be produced
[3 marks]
36 Mass of salt actually produced = g
08.6 Some salts can be produced by reacting sulfuric acid with a metal.
Neither copper nor sodium is used to produce a salt with sulfuric acid.
Give one reason why each metal is not used.
[2 marks]
Copper
Sodium
Mark scheme
Show the mark scheme
Question 8
AO /
Question Answers Extra information Mark
Spec. Ref.
08.1 copper sulfate allow CuSO4 1 AO2
water allow H2O 1 AO1
4.4.2.2
4.4.2.3
RPA1
AO /
Spec. Ref.
08.2 ignore references to colours AO1
1 4.4.2.3
solid remains (in the mixture) allow copper carbonate remains RPA1
(in the mixture)
or
no more effervescence /
bubbles / fizzing
AO /
Spec. Ref.
08.3 to remove copper carbonate allow to remove excess (copper 1 AO1
carbonate) 4.1.1.2
4.4.2.3
RPA1
AO /
Spec. Ref.
08.4 electric heater ignore Bunsen burner 1 AO1
or – – – 4.4.2.3
water bath RPA1
AO /
Spec. Ref.
08.5 mass produced allow 1 AO2
92.8 = × 100 mass produced = 4.3.3.1
12.5
max theoretical mass
% yield ×
92.8
22 (mass produced) = × 12.5 1
= 11.6 (g) 1
AO /
Spec. Ref.
08.6 (copper) AO1
does not react with (sulfuric) allow is unreactive 1
acid allow will not displace hydrogen
allow is below hydrogen in the
reactivity series AO3
ignore is not reactive enough 4.4.1.2
4.4.2.3
(sodium)
could explode allow (the reaction is) dangerous 1
or
could get too hot
Total Question 8 10
How to answer it
Required Practical 1: Making a Soluble Salt & Yield Calculations
This question assesses your understanding of AQA GCSE Chemistry Required Practical 1 (Making Soluble Salts) and quantitative chemistry skills:
- Predicting products for the reaction between an acid and a metal carbonate.
- Observational evidence for an insoluble reactant being in excess.
- Purification techniques (filtration and crystallisation apparatus).
- Rearranging the percentage yield formula to calculate actual yield.
- Explaining chemical reactivity and safety limits using the reactivity series.
Completing the Word Equation
copper carbonate + sulfuric acid → [blank] + [blank] + carbon dioxide
✅ Correct Answer
The two missing products are (in either order):
- copper sulfate (1 mark)
- water (1 mark)
Chemical formulas are accepted ( CuSO₄ and H₂O ), but words are safer to prevent formula errors.
💡 Key Knowledge
Always memorize the general word equation for an acid and a carbonate:
metal carbonate + acid → salt + water + carbon dioxide
- Sulfuric acid always makes sulfate salts.
- Hydrochloric acid makes chloride salts.
- Nitric acid makes nitrate salts.
Observations and Filtration (Steps 4 & 5)
Determining excess and isolating the salt solution
✅ Correct Answers
08.2 Observation of excess (1 mark):
- Solid copper carbonate remains at the bottom (does not dissolve).
- OR No more fizzing / bubbling / effervescence.
08.3 Reason for filtering (1 mark):
- To remove excess / unreacted copper carbonate.
❌ Common Errors & Misconceptions
- "The solution turns blue": The solution turns blue as soon as the first spoonful reacts; this does not prove it is in excess.
- Vague filtration reasons: Writing "to separate the mixture" or "to make it pure" is too vague. You must state what is being filtered out (the unreacted solid).
🧠 Exam Technique: Why add an excess?
We deliberately add excess insoluble base to ensure all the acid is completely neutralised. This guarantees the final salt solution won't be contaminated with leftover acid, which cannot be separated by filtration.
Gentle Heating Apparatus (Step 6)
Apparatus to evaporate water gently
✅ Correct Answer
- Water bath (1 mark)
- OR Electric heater (1 mark)
❌ The Bunsen Burner Trap
The question specifies warming gently.
Direct heating with a Bunsen burner is ignored / not credited because it heats too strongly, which can cause the solution to boil over, spit hot acid/salt, or decompose the copper sulfate crystals into anhydrous copper sulfate.
Calculating Mass Actually Produced (% Yield)
Given: Theoretical mass = 12.5 g; Percentage yield = 92.8%
📐 Step-by-Step Calculation
actual mass = (% yield ÷ 100) × theoretical mass
actual mass = (92.8 ÷ 100) × 12.5
actual mass = 0.928 × 12.5 (1 mark)
Mass = 11.6 g
🧠 Sanity Check Strategy
The actual yield can never be greater than the maximum theoretical yield in a chemical reaction.
Since the theoretical yield is 12.5 g and the yield is 92.8% , your answer must be slightly less than 12.5 g.
If you mistakenly calculated 12.5 ÷ 0.928 = 13.47 g , immediately realize that you have produced more than 100%, meaning your rearrangement is inverted!
Reactivity Series & Salt Preparation
Why neither copper nor sodium is reacted directly with sulfuric acid
✅ Correct Explanations
Why Copper is not used (1 mark):
- Copper does not react with sulfuric acid / is unreactive.
- Alternative: Copper is below hydrogen in the reactivity series / will not displace hydrogen.
Why Sodium is not used (1 mark):
- The reaction is too violent / could explode / gets too hot / is dangerous.
❌ Words That Lose Marks
- For copper: Do NOT say "copper is not reactive enough". The mark scheme explicitly states ignore "not reactive enough". You must state clearly that it does not react at all.
- For sodium: Saying simply "it is a group 1 metal" does not answer the question. You must describe the unsafe outcome (explosion / violent heat release).
Topics
Chemistry · Required Practicals · C3: Quantitative Chemistry · C4: Chemical Changes · Required Practicals
Question and mark scheme from the AQA GCSE Chemistry examination, Chemistry Paper 1 (Foundation), June 2024. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.