2 (a) Magnesium is in Period 3 of the Periodic Table. (i) Use the Periodic Table to name the noble gas in Period 3 of the Periodic Table. … [1] (ii) Describe the change in metallic character across Period 3. … … [1] (b) Magnesium reacts with carbon dioxide. Magnesium oxide and carbon are made. (i) Write the word equation for this reaction. … + … … + … [1] (ii) The reaction between magnesium and carbon dioxide is exothermic. Explain what is meant by an exothermic reaction. … … [1] (c) An atom of magnesium has a proton number (atomic number) of 12 and a nucleon number (mass number) of 24. Complete Table 2.1 to show the names and numbers of the two particles contained in the nucleus of this magnesium atom. Table 2.1 name of particle number of particles [2] (d) Magnesium carbonate reacts with dilute hydrochloric acid to make aqueous magnesium chloride. (i) Magnesium carbonate is insoluble in water. State the separation technique used to remove magnesium carbonate from a mixture of magnesium carbonate and water. … [1] (ii) Magnesium chloride dissolves in water. State the separation technique used to obtain solid magnesium chloride from a solution of magnesium chloride. … [1] (iii) Magnesium carbonate reacts with dilute hydrochloric acid. Complete the balanced symbol equation for this reaction. MgCO3 + …HCl MgCl 2 + CO2 + H2O [1] (iv) Dilute hydrochloric acid contains aqueous chloride ions. State the test for aqueous chloride ions and give the observation for a positive result. test … observation … [2] (e) Table 2.2 shows the composition of a magnesium alloy. Table 2.2 element % by mass magnesium 94 neodymium 2 yttrium 4 (i) Calculate the mass of magnesium in 500 kg of the alloy. … kg [1] (ii) The alloy is used in aircraft bodies. Suggest why the alloy of magnesium is used rather than pure magnesium for aircraft bodies. … … [1] [Total: 13]

2(a)(i) argon ; 1 2(a)(ii) metal to non-metal ; 1 2(b)(i) magnesium + carbon dioxide → carbon + magnesium oxide ; 1 2(b)(ii) thermal energy released ; 1 2(c) protons –12 ; neutrons –12 ; 2 2(d)(i) filtration ; 1 2(d)(ii) crystallisation ; 1 2(d)(iii) MgCO3 + 2HCl → MgCl2 + CO2 + H2O ; 1 2(d)(iv) (acidified) (aqueous) silver nitrate ; white precipitate ; 2 2(e)(i) 470 (kg) ; 1 2(e)(ii) stronger / less dense ; 1 (a)(i) To earn this mark, you must correctly identify 'argon' as the noble gas in Period 3. (a)(ii) To earn this mark, you must describe the change in metallic character across Period 3 as going from 'metal to non-metal'. (b)(i) To earn this mark, you must write the correct word equation: 'magnesium + carbon dioxide → carbon + magnesium oxide'. (b)(ii) To earn this mark, you must explain that an exothermic reaction is one where 'thermal energy is released'. (c) To earn these two marks, you must correctly state that the nucleus contains 'protons – 12' and 'neutrons – 12'. (d)(i) To earn this mark, you must identify 'filtration' as the correct separation technique. (d)(ii) To earn this mark, you must identify 'crystallisation' as the correct separation technique. (d)(iii) To earn this mark, you must write the correct balanced chemical equation: 'MgCO3 + 2HCl → MgCl2 + CO2 + H2O'. (d)(iv) To earn these two marks, you must state the use of '(acidified) (aqueous) silver nitrate' and observe a 'white precipitate'. (e)(i) To earn this mark, you must state the correct value '470 (kg)'. (e)(ii) To earn this mark, you must state that the alloy is 'stronger / less dense' than pure magnesium.

2 (a) Magnesium is in Period 3 of the Periodic Table. (i) Use the Periodic Table to name the noble gas in Period 3 of the Periodic Table. … [1] (ii) Describe the change in metallic character across Period 3. … … [1] (b) Magnesium reacts with carbon dioxide. Magnesium oxide and carbon are made. (i) Write the word equation for this reaction. … + … … + … [1] (ii) The reaction between magnesium and carbon dioxide is exothermic. Explain what is meant by an exothermic reaction. … … [1] (c) An atom of magnesium has a proton number (atomic number) of 12 and a nucleon number (mass number) of 24. Complete Table 2.1 to show the names and numbers of the two particles contained in the nucleus of this magnesium atom. Table 2.1 name of particle number of particles [2] (d) Magnesium carbonate reacts with dilute hydrochloric acid to make aqueous magnesium chloride. (i) Magnesium carbonate is insoluble in water. State the separation technique used to remove magnesium carbonate from a mixture of magnesium carbonate and water. … [1] (ii) Magnesium chloride dissolves in water. State the separation technique used to obtain solid magnesium chloride from a solution of magnesium chloride. … [1] (iii) Magnesium carbonate reacts with dilute hydrochloric acid. Complete the balanced symbol equation for this reaction. MgCO3 + …HCl MgCl 2 + CO2 + H2O [1] (iv) Dilute hydrochloric acid contains aqueous chloride ions. State the test for aqueous chloride ions and give the observation for a positive result. test … observation … [2] (e) Table 2.2 shows the composition of a magnesium alloy. Table 2.2 element % by mass magnesium 94 neodymium 2 yttrium 4 (i) Calculate the mass of magnesium in 500 kg of the alloy. … kg [1] (ii) The alloy is used in aircraft bodies. Suggest why the alloy of magnesium is used rather than pure magnesium for aircraft bodies. … … [1] [Total: 13]

2(a)(i) argon ; 1 2(a)(ii) metal to non-metal ; 1 2(b)(i) magnesium + carbon dioxide → carbon + magnesium oxide ; 1 2(b)(ii) thermal energy released ; 1 2(c) protons –12 ; neutrons –12 ; 2 2(d)(i) filtration ; 1 2(d)(ii) crystallisation ; 1 2(d)(iii) MgCO3 + 2HCl → MgCl2 + CO2 + H2O ; 1 2(d)(iv) (acidified) (aqueous) silver nitrate ; white precipitate ; 2 2(e)(i) 470 (kg) ; 1 2(e)(ii) stronger / less dense ; 1 (a)(i) To earn this mark, you must correctly identify 'argon' as the noble gas in Period 3. (a)(ii) To earn this mark, you must describe the change in metallic character across Period 3 as going from 'metal to non-metal'. (b)(i) To earn this mark, you must write the correct word equation: 'magnesium + carbon dioxide → carbon + magnesium oxide'. (b)(ii) To earn this mark, you must explain that an exothermic reaction is one where 'thermal energy is released'. (c) To earn these two marks, you must correctly state that the nucleus contains 'protons – 12' and 'neutrons – 12'. (d)(i) To earn this mark, you must identify 'filtration' as the correct separation technique. (d)(ii) To earn this mark, you must identify 'crystallisation' as the correct separation technique. (d)(iii) To earn this mark, you must write the correct balanced chemical equation: 'MgCO3 + 2HCl → MgCl2 + CO2 + H2O'. (d)(iv) To earn these two marks, you must state the use of '(acidified) (aqueous) silver nitrate' and observe a 'white precipitate'. (e)(i) To earn this mark, you must state the correct value '470 (kg)'. (e)(ii) To earn this mark, you must state that the alloy is 'stronger' or 'less dense' than pure magnesium.

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.

5 (a) Petroleum is separated into useful fractions by fractional distillation. Fig. 5.1 shows a simplified diagram for the fractional distillation of petroleum. hot petroleum fraction naphtha refinery gas diesel oil 400 °C 50 °C … … Fig. 5.1 (i) On Fig. 5.1 write the names of the missing fractions in their correct place. [2] (ii) State one use for the refinery gas fraction. … [1] (iii) State why the process of fractional distillation is a physical change and not a chemical change. … … [1] (b) The diesel oil fraction is used as a fuel. (i) Diesel oil is a mixture of hydrocarbons. State what is meant by the term hydrocarbon. … … … [2] (ii) State the two products of the complete combustion of a hydrocarbon. 1 … 2 … [2] (c) (i) Name the process that produces small alkene molecules from larger alkane molecules. … [1] (ii) State how the molecular structure of an alkane molecule differs from the molecular structure of an alkene molecule. … … [1] (iii) Aqueous bromine is used to test for an alkene. State the colour change when aqueous bromine reacts with an alkene. from … to … [2] [Total: 12]

5(a)(i) gasoline ; bitumen ; 2 5(a)(ii) fuel ; 1 5(a)(iii) no new substances formed ; 1 5(b)(i) substance that contains carbon and hydrogen (atoms) ; only ; 2 5(b)(ii) carbon dioxide ; water ; 2 5(c)(i) cracking ; 1 5(c)(ii) alkane does not contain a C-C double bond / alkene does contain a C-C double bond / contains only single bonds ; 1 5(c)(iii) orange ; to colourless ; 2

Cambridge IGCSE Co-ordinated Sciences · 0654

IGCSE Co-ordinated Sciences (0654) Experimental techniques and chemical analysis past paper questions

Revise IGCSE Co-ordinated Sciences (0654) — Experimental techniques and chemical analysis 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.

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

Experimental techniques and chemical analysis in IGCSE Co-ordinated Sciences 0654 exams, 2020–2025

Across 2020–2025, Experimental techniques and chemical analysis accounted for 335 questions worth 2,412 marks in Cambridge IGCSE Co-ordinated Sciences (0654) papers.

By year
Year	Questions	Marks
2020	52	352
2021	61	402
2022	39	321
2023	64	459
2024	64	464
2025	55	414

Most-tested subtopics

C12.1 Experimental design1233 marks
C12.5 Identification of ions and gases785 marks
C12.4 Separation and purification309 marks

Appears in

Paper 1 · 54 qs
Paper 2 · 38 qs
Paper 3 · 32 qs
Paper 4 · 21 qs
Paper 5 · 93 qs
Paper 6 · 97 qs

All most-tested Co-ordinated Sciences topics

2021 May/Jun · Paper 3 · Q2 · 13 marks
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2021 May/Jun · Paper 3 · Q2 · 13 marks
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2021 Oct/Nov · Paper 3 · Q2 · 9 marks
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2021 Oct/Nov · Paper 3 · Q5 · 12 marks
$5 (a) Petroleum is separated into useful fractions by fractional distillation. Fig. 5.1 shows a simplified diagram for the…$ $5 (a) Petroleum is separated into useful fractions by fractional distillation. Fig. 5.1 shows a simplified diagram for the… (continued)$
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2021 Feb/Mar · Paper 1 · Q14 · 1 mark
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Mark scheme — 2021 Paper 1 Q14
Answer: A
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