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) 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) 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'.

20 A label from a packet of indigestion tablets is shown. Each tablet contains: magnesium carbonate 120 mg magnesium hydroxide 15 mg magnesium oxide 62 mg magnesium sulfate 47 mg Which substance does not neutralise stomach acid? A magnesium carbonate B magnesium hydroxide C magnesium oxide D magnesium sulfate

Answer: D To earn the mark, a student must identify magnesium sulfate as the substance that does not neutralize stomach acid.

Cambridge IGCSE Co-ordinated Sciences · 0654

IGCSE Co-ordinated Sciences (0654) Acids, bases and salts past paper questions

Revise IGCSE Co-ordinated Sciences (0654) — Acids, bases and salts 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.

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

Acids, bases and salts in IGCSE Co-ordinated Sciences 0654 exams, 2020–2025

Across 2020–2025, Acids, bases and salts accounted for 250 questions worth 1,356 marks in Cambridge IGCSE Co-ordinated Sciences (0654) papers.

By year
Year	Questions	Marks
2020	42	212
2021	44	223
2022	40	219
2023	46	250
2024	39	228
2025	39	224

Most-tested subtopics

C7.1 The characteristic properties of acids and bases1055 marks
C7.3 Preparation of salts268 marks
C7.2 Oxides75 marks

Appears in

Paper 1 · 66 qs
Paper 2 · 63 qs
Paper 3 · 51 qs
Paper 4 · 14 qs
Paper 5 · 24 qs
Paper 6 · 32 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 · 13 marks
Marking scheme
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2021 May/Jun · Paper 3 · Q2 · 13 marks
Marking scheme
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2021 Oct/Nov · Paper 3 · Q2 · 12 marks
Marking scheme
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2021 Feb/Mar · Paper 1 · Q20 · 1 mark
Marking scheme
Mark scheme — 2021 Paper 1 Q20
Answer: D
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