Pearson Edexcel International GCSE in Chemistry · 4CH1 · Free · no account needed
Formulae and Balanced Equations — exam questions
12 original Incandio exam-style questions on Formulae and Balanced Equations, 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 Formulae and Balanced Equations — 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
- Determine (1–4 marks)
- a value reached by combining given data with a method the learner selects
- Write (1–3 marks)
- the equation, formula or ionic equation, balanced, with state symbols where asked
- Complete (1–4 marks)
- the missing entries in a table, equation or diagram
- 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
- Calculate (1–4 marks)
- a numerical answer with working, to the stated precision
- Suggest (1–3 marks)
- a plausible answer applying taught chemistry to an unfamiliar substance
Assessed on Paper 1 (4CH1/1C) and Paper 2 (4CH1/2C), against AO1, AO2.
Where these sit in the specification
Pearson Edexcel International GCSE Chemistry (4CH1) — statements 1.25 · 1.26. 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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Table 1 — three reactions, with the equation for each written out but not yet balanced. Reaction Unbalanced equation 1 Ca + H₂O → Ca(OH)₂ + H₂ 2 CH₄ + O₂ → CO₂ + H₂O 3 Na + O₂ → Na₂O (a)
(2)Complete
Complete the balancing of reaction 1 in Table 1.
Table 1 — three reactions, with the equation for each written out but not yet balanced. Reaction Unbalanced equation 1 Ca + H₂O → Ca(OH)₂ + H₂ 2 CH₄ + O₂ → CO₂ + H₂O 3 Na + O₂ → Na₂O (b)
(3)Complete
Complete the balancing of reaction 2 in Table 1, and add state symbols for a reaction carried out at room temperature.
Table 1 — three reactions, with the equation for each written out but not yet balanced. Reaction Unbalanced equation 1 Ca + H₂O → Ca(OH)₂ + H₂ 2 CH₄ + O₂ → CO₂ + H₂O 3 Na + O₂ → Na₂O (c)
(2)Complete
Complete the balancing of reaction 3 in Table 1.
Table 1 — three reactions, with the equation for each written out but not yet balanced. Reaction Unbalanced equation 1 Ca + H₂O → Ca(OH)₂ + H₂ 2 CH₄ + O₂ → CO₂ + H₂O 3 Na + O₂ → Na₂O (d)
(2)Explain
Explain why reaction 3 cannot be balanced by writing 2Na + O₂ → Na₂O₂.
Table 1 — three reactions, with the equation for each written out but not yet balanced. Reaction Unbalanced equation 1 Ca + H₂O → Ca(OH)₂ + H₂ 2 CH₄ + O₂ → CO₂ + H₂O 3 Na + O₂ → Na₂O (Total for Question 1 = 9 marks)
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(1)Which
Which state symbol shows that a substance is dissolved in water?
Symbol A (s) B (l) C (g) D (aq) (Total for Question 2 = 1 mark)
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(2)Determine
A metal sulfate has the formula MSO₄ and a relative formula mass of 160. Determine the relative atomic mass of the metal M.
Relative atomic masses — H = 1, C = 12, N = 14, O = 16, Na = 23, S = 32, Ca = 40
(Total for Question 3 = 2 marks)
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(2)Write
Write the word equation for the reaction between magnesium and hydrochloric acid.
(Total for Question 4 = 2 marks)
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(2)Complete
Complete the balancing of this equation: __ Al + __ O₂ → __ Al₂O₃
(Total for Question 5 = 2 marks)
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(2)Explain
Explain why a chemical equation must be balanced.
(Total for Question 6 = 2 marks)
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(3)Calculate
Calculate the percentage by mass of nitrogen in the fertiliser ammonium nitrate, NH₄NO₃, which has a relative formula mass of 80.
Relative atomic masses — H = 1, C = 12, N = 14, O = 16, Na = 23, S = 32, Ca = 40
percentage by mass of nitrogen = ............................ %
(Total for Question 7 = 3 marks)
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(2)Suggest
A student writes: Mg + O₂ → MgO₂. Suggest what is wrong with this equation.
(Total for Question 8 = 2 marks)
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(4)Calculate
Calculate the percentage by mass of iron in iron(III) oxide, Fe₂O₃.
Given — Relative atomic masses: O = 16, Fe = 56.
percentage of iron = ............................ %
(Total for Question 9 = 4 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 Formulae and Balanced Equations to Ember, an AI pupil who does not have it yet and asks the awkward question.
- Defend it — argue it against Antoine Lavoisier over three rounds, marked against descriptors you can read first.
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Back to the lesson
- Formulae and Balanced Equations — Why the ash weighs more than the metal, what balancing an equation is really doing, and how to add up a formula mass without losing a bracket.
- All of Incandio Chemistry · Incandio Exam Practice