2 (a) Copper and sodium are metals. Copper is a transition element. Sodium is not a transition element. It is found in Group I of the Periodic Table. Some properties of metallic elements are listed. A act as a catalyst B form coloured compounds C good conductor of electricity D good conductor of thermal energy E malleable F non-magnetic State the letters (A to F) of the two properties that describe copper but do not describe sodium. … and … [2] (b) Copper(II) oxide is heated with carbon. Copper and carbon dioxide are made. (i) Construct the word equation for the reaction between copper(II) oxide and carbon. + + [1] (ii) State the chemical test for carbon dioxide gas and the observation for a positive result. test … observation … [2] (iii) Explain why copper(II) oxide is described as a basic oxide. … … [1] (c) Metals can be coated with a layer of copper using electroplating. Electroplating uses the process of electrolysis. Use words from the list to complete the sentence to define the term electrolysis. Each word may be used once or not at all. covalent electricity gas ionic molten solid solution time water Electrolysis always involves the breakdown of … compounds when … or in aqueous … by the passage of … . [2] (d) Bronze is a mixture of copper and tin. (i) State the term used to describe a mixture of metals. … [1] (ii) Apart from cost, suggest why bronze is used to make coins but pure copper is not used to make coins. … … [1] [Total: 10]

2(a) A; B; 2 2(b)(i) copper oxide + carbon → copper + carbon dioxide; 1 2(b)(ii) (bubble through) limewater; goes cloudy / milky; 2 2(b)(iii) produces solution with pH above 7 / copper(II) oxide is a metal oxide; 1 2(c) ionic molten solution electricity;; 2 2(d)(i) alloy; 1 2(d)(ii) tougher / stronger; 1 (a) To earn the marks, you must state both 'A' and 'B' as the properties that describe copper but not sodium. (b)(i) To earn the mark, you must write the complete and correct word equation: copper oxide + carbon → copper + carbon dioxide. (b)(ii) To earn the marks, you must state 'limewater' as the test and 'goes cloudy/milky' as the observation for carbon dioxide. (b)(iii) To earn the mark, you must explain that copper(II) oxide is a basic oxide because it produces a solution with a pH above 7 or is a metal oxide. (c) To earn the marks, you must correctly identify 'ionic', 'molten', 'solution', and 'electricity' as the conditions for electrolysis. (d)(i) To earn the mark, you must state 'alloy' as the term for a mixture of metals. (d)(ii) To earn the mark, you must state that an alloy is 'tougher' or 'stronger' than a pure metal.

2 (a) Table 2.1 shows information about three Group VII elements. Table 2.1 element formula colour physical state at 20 °C chlorine Cl 2 gas bromine orange iodine I2 grey (i) Complete Table 2.1. [3] (ii) State the name given to the Group VII elements in the Periodic Table. … [1] (b) Bromine reacts with hydrogen to make hydrogen bromide. Construct the word equation for this reaction. … + … … [1] (c) Aqueous bromine is orange. Predict the colour change, if any, when aqueous bromine is mixed with ethene gas. Explain your answer. colour change … explanation … … [2] (d) An aqueous solution is tested to see if bromide ions are present. State the test for aqueous bromide ions and give the observation for a positive result. test … observation … [2] (e) Fig. 2.1 shows the electrolysis of molten lead(II) bromide using inert electrodes. + – cathode molten lead(II) bromide anode low voltage d.c. supply Fig. 2.1 Identify the substances formed at the cathode and the anode. at cathode … at anode … [2] [Total: 11]

2(a)(i) formula Br2; colour (pale) green for Cl2 ; physical state liquid for Br2 and solid for I2 ; 3 2(a)(ii) halogens ; 1 2(b) hydrogen + bromine → hydrogen bromide ; 1 2(c) (orange to) colourless; ethene is unsaturated / has a double bond ; 2 2(d) (aqueous) silver nitrate ; cream coloured precipitate ; 2 2(e) cathode – lead ; anode – bromine ; 2

2 (a) Table 2.1 shows the melting points and reactivity with water of three Group I metals. Table 2.1 element melting point / °C reactivity with water lithium 181 … sodium 98 forms bubbles of gas rapidly potassium … forms bubbles of gas very rapidly Complete Table 2.1 to predict • the melting point of potassium • the reactivity of lithium with water. [2] (b) Name the gas made when a Group I metal reacts with water. … [1] (c) When sodium reacts with chlorine, an orange flame is seen and the sodium melts. Sodium chloride is formed. (i) State if the reaction is exothermic or endothermic. Explain your answer. reaction is … explanation … … [1] (ii) Sodium chloride contains chloride ions. Describe a test for chloride ions and the positive result. test … result … [2] (iii) State the type of bonding present in sodium chloride. Explain your answer. type of bonding … explanation … … [2] (d) Concentrated aqueous sodium chloride is electrolysed. State the products at the electrodes. … and … [2] (e) A student separates a mixture of sand and aqueous sodium chloride. (i) State the method of separation used to separate the sand from the aqueous sodium chloride. … [1] (ii) Describe how solid sodium chloride can be obtained from aqueous sodium chloride. … … [1] [Total: 12]

2(a) below 90 °C ; reacts / forms bubbles of gas slowly / moderately ; 2 2(b) hydrogen ; 1 2(c)(i) exothermic because (thermal) energy released (to melt sodium) ; 1 2(c)(ii) aqueous silver nitrate ; white precipitate ; 2 2(c)(iii) ionic ; bonding between a metal and a non-metal / electron transfer ; 2 2(d) hydrogen ; chlorine ; 2 2(e)(i) filtration ; 1 2(e)(ii) evaporation / crystallisation ; 1 To earn marks, you must correctly predict potassium's melting point as below 90°C and lithium's reactivity as slowly forming bubbles of gas. For part (b), state 'hydrogen'. For (c)(i), identify the reaction as 'exothermic' and explain that thermal energy is released. For (c)(ii), describe the test as adding aqueous silver nitrate and the positive result as a 'white precipitate'.

2 (a) The formula of sulfuric acid is H2SO4. (i) State the number of different elements shown in this formula. … [1] (ii) State the total number of atoms shown in this formula. … [1] (b) Fig. 2.1 shows the electrolysis of dilute sulfuric acid using carbon electrodes. d.c. power supply dilute sulfuric acid gas Q gas P + – Fig. 2.1 (i) Name gas P and gas Q. gas P … gas Q … [2] (ii) State the name of the positive electrode. … [1] (c) Dilute sulfuric acid reacts with some metals. (i) Suggest a pH for dilute sulfuric acid. pH … [1] (ii) State a metal element that does not react with dilute sulfuric acid. … [1] (iii) Name the gas made when dilute sulfuric acid reacts with zinc. … [1] (iv) When dilute sulfuric acid reacts with zinc, an aqueous solution of zinc sulfate is made. State a method used to separate zinc sulfate from water. … [1] [Total: 9]

2(a)(i) 3 ; 1 2(a)(ii) 7 ; 1 2(b)(i) P – oxygen ; Q – hydrogen ; 2 2(b)(ii) anode ; 1 2(c)(i) any number less than 7 ; 1 2(c)(ii) copper ; 1 2(c)(iii) hydrogen ; 1 2(c)(iv) evaporation / crystallisation ; 1 (a)(i) To earn this mark, you must state the number of different elements present in the formula H2SO4. (a)(ii) To earn this mark, you must state the total count of all atoms in the formula H2SO4. (b)(i) To earn these marks, you must correctly name the gas produced at electrode P and the gas produced at electrode Q during the electrolysis. (b)(ii) To earn this mark, you must state the correct name for the positive electrode. (c)(i) To earn this mark, you must suggest any pH value that is less than 7, indicating an acidic solution. (c)(ii) To earn this mark, you must state the name of a metal element that does not react with dilute sulfuric acid. (c)(iii) To earn this mark, you must name the specific gas produced when dilute sulfuric acid reacts with zinc. (c)(iv) To earn this mark, you must state a suitable method for obtaining solid zinc sulfate from its aqueous solution.

Cambridge IGCSE Co-ordinated Sciences · 0654

IGCSE Co-ordinated Sciences (0654) Electrochemistry past paper questions

Revise IGCSE Co-ordinated Sciences (0654) — Electrochemistry with real Cambridge past-paper questions grouped by topic, each shown with its marking scheme. Working one topic at a time targets exactly the skill each question tests.

100 free questions from 2016–2021, each with its marking scheme. Open the full topical bank to filter by subtopic, paper, and year.

Electrochemistry in IGCSE Co-ordinated Sciences 0654 exams, 2020–2025

Across 2020–2025, Electrochemistry accounted for 140 questions worth 697 marks in Cambridge IGCSE Co-ordinated Sciences (0654) papers.

By year
Year	Questions	Marks
2020	17	72
2021	25	127
2022	25	116
2023	20	77
2024	29	161
2025	24	144

Most-tested subtopics

C4.1 Electrolysis593 marks
C4.2 Hydrogen–oxygen fuel cells32 marks

Appears in

Paper 1 · 39 qs
Paper 2 · 33 qs
Paper 3 · 34 qs
Paper 4 · 24 qs
Paper 5 · 5 qs
Paper 6 · 5 qs

All most-tested Co-ordinated Sciences topics

2021 Feb/Mar · Paper 3 · Q2 · 10 marks
Marking scheme
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2021 May/Jun · Paper 3 · Q2 · 11 marks
Marking scheme
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2021 Oct/Nov · Paper 3 · Q2 · 12 marks
Marking scheme
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2021 Oct/Nov · Paper 3 · Q2 · 9 marks
Marking scheme
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2021 Feb/Mar · Paper 1 · Q16 · 1 mark
Marking scheme
Mark scheme — 2021 Paper 1 Q16
Answer: D
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