Pearson Edexcel International GCSE in Chemistry · 4CH1 · Free · no account needed
Preparing a Soluble Salt — exam questions
12 original Incandio exam-style questions on Preparing a Soluble Salt, 27 marks, about 27 minutes of writing. Each one carries the command word, the tariff and the specification statement it assesses, exactly as a paper presents them. This is an original Incandio practice question, written to reflect the structure and demands of the qualification. It is not an official Pearson Edexcel past-paper question.
This is the practice set for Preparing a Soluble Salt — the lesson that teaches it. Read the lesson first if the idea is new; come here when you want to find out whether you can turn it into marks. Completely free, no account needed to read.
What these questions ask of you
7 command words run through this set, and on Pearson Edexcel International GCSE Chemistry each one means something precise. Answering the wrong command is the commonest way a candidate who understands the lesson still loses the mark.
- Which (1 mark)
- one option chosen from the set given
- Name (1 mark)
- the correct chemical name
- Give (1–2 marks)
- a short factual answer — the most common chemistry command
- Describe (2–5 marks)
- developed, linked statements of what happens or what is observed Misread as: giving one bare observation where the tariff asked for a developed account
- Explain (2–4 marks)
- the reason, in terms of particles, bonding, energy or equilibrium Misread as: describing the observation without giving the chemistry that causes it
- Suggest (1–3 marks)
- a plausible answer applying taught chemistry to an unfamiliar substance
- Write (1–3 marks)
- the equation, formula or ionic equation, balanced, with state symbols where asked
Assessed on Paper 1 (4CH1/1C) and Paper 2 (4CH1/2C), against AO1, AO2, AO3.
Where these sit in the specification
Pearson Edexcel International GCSE Chemistry (4CH1) — statements 2.39 · 2.42. Incandio is aligned to this specification; it is not published by, endorsed by or affiliated with Pearson, and it reproduces none of Pearson's wording.
The 12 questions
Answer them on paper, then open the lesson's exam practice to have them marked. The mark scheme, the accepted and rejected answers and the annotated model answer are in Incandio and are not printed here — an answer beside its question is not practice.
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A student prepared hydrated copper(II) sulfate crystals. She warmed 50 cm³ of dilute sulfuric acid, added black copper(II) oxide powder a spatula at a time and stirred, until some powder remained undissolved. She filtered the mixture, heated the blue filtrate until crystals began to appear at the edge, then left it on a windowsill for two days.
(a)
(1)Give
Give the name of the salt in the blue filtrate.
A student prepared hydrated copper(II) sulfate crystals. She warmed 50 cm³ of dilute sulfuric acid, added black copper(II) oxide powder a spatula at a time and stirred, until some powder remained undissolved. She filtered the mixture, heated the blue filtrate until crystals began to appear at the edge, then left it on a windowsill for two days.
(b)
(2)Write
Write the balanced symbol equation for the reaction that took place in the beaker.
A student prepared hydrated copper(II) sulfate crystals. She warmed 50 cm³ of dilute sulfuric acid, added black copper(II) oxide powder a spatula at a time and stirred, until some powder remained undissolved. She filtered the mixture, heated the blue filtrate until crystals began to appear at the edge, then left it on a windowsill for two days.
(c)
(3)Explain
Explain why the student stopped heating the filtrate as soon as crystals appeared at the edge.
A student prepared hydrated copper(II) sulfate crystals. She warmed 50 cm³ of dilute sulfuric acid, added black copper(II) oxide powder a spatula at a time and stirred, until some powder remained undissolved. She filtered the mixture, heated the blue filtrate until crystals began to appear at the edge, then left it on a windowsill for two days.
(d)
(3)Suggest
Suggest why this method would not work for preparing copper(II) sulfate from copper metal instead of copper(II) oxide.
A student prepared hydrated copper(II) sulfate crystals. She warmed 50 cm³ of dilute sulfuric acid, added black copper(II) oxide powder a spatula at a time and stirred, until some powder remained undissolved. She filtered the mixture, heated the blue filtrate until crystals began to appear at the edge, then left it on a windowsill for two days.
(Total for Question 1 = 9 marks)
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(1)Which
Which piece of apparatus is used to separate an excess solid from a solution?
Apparatus A a filter funnel and filter paper B a burette C a condenser D a separating funnel (Total for Question 2 = 1 mark)
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(1)Name
Name the solid that is left on the filter paper in this preparation.
A student prepared hydrated copper(II) sulfate crystals. She warmed 50 cm³ of dilute sulfuric acid, added black copper(II) oxide powder a spatula at a time and stirred, until some powder remained undissolved. She filtered the mixture, heated the blue filtrate until crystals began to appear at the edge, then left it on a windowsill for two days.
(Total for Question 3 = 1 mark)
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(1)Give
Give the colour of hydrated copper(II) sulfate crystals.
(Total for Question 4 = 1 mark)
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(2)Describe
Describe how crystals are obtained from the filtrate once the filtration is complete.
A student prepared hydrated copper(II) sulfate crystals. She warmed 50 cm³ of dilute sulfuric acid, added black copper(II) oxide powder a spatula at a time and stirred, until some powder remained undissolved. She filtered the mixture, heated the blue filtrate until crystals began to appear at the edge, then left it on a windowsill for two days.
(Total for Question 5 = 2 marks)
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(3)Explain
Explain why the copper(II) oxide is added until some of it remains undissolved.
A student prepared hydrated copper(II) sulfate crystals. She warmed 50 cm³ of dilute sulfuric acid, added black copper(II) oxide powder a spatula at a time and stirred, until some powder remained undissolved. She filtered the mixture, heated the blue filtrate until crystals began to appear at the edge, then left it on a windowsill for two days.
(Total for Question 6 = 3 marks)
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(2)Explain
Explain why the acid is warmed before the copper(II) oxide is added.
A student prepared hydrated copper(II) sulfate crystals. She warmed 50 cm³ of dilute sulfuric acid, added black copper(II) oxide powder a spatula at a time and stirred, until some powder remained undissolved. She filtered the mixture, heated the blue filtrate until crystals began to appear at the edge, then left it on a windowsill for two days.
(Total for Question 7 = 2 marks)
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(3)Suggest
A second student evaporated her filtrate to dryness over a Bunsen burner. Suggest two ways in which her product would be worse than crystals grown slowly.
A student prepared hydrated copper(II) sulfate crystals. She warmed 50 cm³ of dilute sulfuric acid, added black copper(II) oxide powder a spatula at a time and stirred, until some powder remained undissolved. She filtered the mixture, heated the blue filtrate until crystals began to appear at the edge, then left it on a windowsill for two days.
(Total for Question 8 = 3 marks)
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(5)Describe
Describe how a pure dry sample of zinc sulfate crystals could be prepared from zinc oxide and dilute sulfuric acid.
(Total for Question 9 = 5 marks)
Have them marked, then defend the answer
Practice tells you the mark; teaching it back tells you whether you understand it. On Incandio a topic counts as mastered only once you have taught it and defended it.
- Mark these questions — 12 questions, marked on Incandio against the authored scheme, with the mistake you actually made named.
- Teach it — explain Preparing a Soluble Salt to Ember, an AI pupil who does not have it yet and asks the awkward question.
- Defend it — argue it against Robert Boyle over three rounds, marked against descriptors you can read first.
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Back to the lesson
- Preparing a Soluble Salt — Add too much on purpose, filter the excess away, and crystallise what is left.
- All of Incandio Chemistry · Incandio Exam Practice