AQA GCSE Combined Science: Trilogy Chemistry Paper 1 (Foundation), 2020: Question 1

9 marks · Low Demand difficulty · Multiple Choice

Answer a set of short questions about acids, bases, salts, ions, reaction rate, filtration and crystallisation in the context of copper oxide reacting with acid.

Practise this question

Question

A chemistry question sheet titled 'This question is about acids and bases' with nine one-mark parts labelled 01.1 to 01.9. The first four parts are multiple-choice/tick-box questions asking for the pH of sulfuric acid, which acid reacts with zinc to make zinc chloride, what type of substance zinc chloride is, and which compound is an alkali. The next parts ask for the formula of copper oxide from Cu2+ and O2− ions, how to speed up the reaction of acid with copper oxide, which word completes a sentence about adding copper oxide until the acid is blank, which apparatus is used to filter unreacted copper oxide, and finally the process used to produce crystals of a salt from a salt solution. For 01.8 there are four filtration/apparatus diagrams shown as options, including a beaker with a container, a distillation setup, a funnel shape, and an evaporating basin.
Question text

01 This question is about acids and bases.

01.1 What is the pH of sulfuric acid?

[1 mark]

Tick ( ) one box.

17 14

01.2 An acid reacts with zinc to produce zinc chloride and hydrogen.

Which acid reacts with zinc to produce zinc chloride?

[1 mark]

Tick ( ) one box.

Hydrochloric acid

Nitric acid

Sulfuric acid

01.3 What type of substance is zinc chloride?

[1 mark]

Tick ( ) one box.

Alkali Base 3 Salt

01.4 An alkali is a base in solution.

Which compound is an alkali?

[1 mark]

Tick ( ) one box.

Sodium hydroxide

Sodium nitrate

Sodium sulfate

01.5 The formula of the copper ion is Cu2+

The formula of the oxide ion is O2–

What is the formula of copper oxide?

[1 mark]

Tick ( ) one box.

Cu2O2 CuO2 4 CuO

A student reacts an acid with copper oxide.

01.6 The reaction between the acid and copper oxide is very slow at

room temperature.

How could the student speed up the reaction?

[1 mark]

01.7 Complete the sentence to show how the student makes sure that all the

acid reacts.

Choose the answer from the box.

[1 mark]

in excess in solution molten soluble

The student adds copper oxide to the acid until the

copper oxide is .

01.8 The student filters the unreacted copper oxide from the solution.

Which apparatus does the student use?

[1 mark]

Tick ( ) one box.

01.9 What process is used to produce crystals of a salt from a salt solution?

[1 mark]

Mark scheme

Show the mark scheme The mark scheme lists answers for questions 01.1 to 01.9 in a table with one mark each. The accepted answers are pH 1, hydrochloric acid, salt, sodium hydroxide, CuO, any one of increasing acid concentration, increasing surface area of copper oxide, or warming the mixture for the rate question, in excess, the funnel apparatus for filtration, and crystallisation for making salt crystals, with evaporation allowed as an alternative. The AO/spec references shown include chemistry content on acids, rates of reaction, and practical techniques.

AO /

Question Answers Extra information Mark

Spec. Ref.

01.1 1 1 AO1

5.4.2.4

01.2 hydrochloric acid 1 AO1

5.4.2.1

5.4.2.2

01.3 salt 1 AO1

5.4.2.1

5.4.2.2

01.4 sodium hydroxide 1 AO2

5.4.2.2

01.5 CuO 1 AO2

5.1.1.1

01.6 any one from: 1 AO1

• increase the concentration of 5.4.2.2

the acid 5.4.2.3

• increase the surface area of allow use powdered copper RPA8

the copper oxide oxide

• warm / heat the mixture ignore increase room

temperature

allow add catalyst

ignore stir

01.7 in excess 1 AO1

5.1.1.2

5.4.2.3

RPA8

01.8 1 AO1

5.1.1.2

5.4.2.3

RPA8

01.9 crystallisation allow evaporation 1 AO1

5.4.2.2

5.4.2.3

RPA8

Total 9

How to answer it

Acids, Bases, and Salt Preparation

What this question tests

This question assesses your knowledge of the pH scale, the chemical properties of acids and bases, and the practical steps involved in the Required Practical Activity (RPA) for making a soluble salt from an insoluble base.

Parts 01.1 – 01.5: Core Chemical Knowledge

Key Concepts

  • pH Scale: Acids have a pH below 7. Sulfuric acid is a strong acid, typically having a pH of 1.
  • Reactions: Acid + Metal → Salt + Hydrogen.
  • Definitions: A salt is the product of an acid-base reaction. An alkali is a base that is soluble in water (e.g., sodium hydroxide).
  • Formulas: Copper(II) ion is Cu²⁺ and oxide ion is O²⁻. Charges must balance to zero, so the formula is CuO.

Correct Answers

01.1: 1 | 01.2: Hydrochloric acid | 01.3: Salt | 01.4: Sodium hydroxide | 01.5: CuO

Parts 01.6 – 01.9: Practical Techniques (RPA)

Part 01.6: Speeding up reactions

Exam Technique

To increase the rate of reaction, you can: heat the mixture, increase the concentration of the acid, or increase the surface area of the solid (using powder instead of lumps).

Part 01.7: Ensuring full reaction

Key Knowledge

We add the base in excess to ensure that all the acid has reacted. If we didn't, some acid would remain, contaminating the final salt.

Part 01.8: Filtration

Apparatus

The correct apparatus is the filter funnel. This is used to remove the unreacted solid (excess base) from the liquid salt solution.

Part 01.9: Crystallisation

Key Knowledge

To obtain solid crystals from a salt solution, we use crystallisation (or evaporation). This involves heating the solution to remove the solvent, leaving the solid salt behind.

Common Errors

  • Confusing "alkali" with any base. Remember: all alkalis are bases, but not all bases are alkalis (only those that dissolve).
  • Forgetting that "in excess" is the standard phrase for ensuring complete reaction of the limiting reagent.
  • Mixing up distillation apparatus (condenser) with filtration apparatus (funnel).

Topics

Chemistry · C4: Chemical Changes · C6: The Rate and Extent of Chemical Change · C8: Chemical Analysis

Question and mark scheme from the AQA GCSE Combined Science: Trilogy examination, Chemistry Paper 1 (Foundation), 2020. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.