Redox — Paper 1 · IGCSE Science - Combined 0653

22 Hydrogen is passed over heated copper(II) oxide as shown. copper(II) oxide hydrogen drops of liquid heat The copper(II) oxide is reduced. Which other statement also describes a change that occurs during the reaction? A Copper is distilled. B Copper(II) oxide is thermally decomposed. C Hydrogen is condensed. D Hydrogen is oxidised.

1 marks

Answer: D

This question in 0653/11 Oct/Nov 2006

19 Which method is used to obtain iron from iron(III) oxide? A combustion B electrolysis C reduction D thermal decomposition

1 marks

Answer: C

This question in 0653/11 May/June 2007

25 Which substance is reduced during the following reaction? A B C D lead(II) oxide + hydrogen → lead + water

1 marks

Answer: A

This question in 0653/11 May/June 2007

19 An oxide of lead is changed to lead by heating it with carbon. Pb xO y + 2C 3Pb + 2CO2 What is the formula of this oxide of lead? A Pb2O3 B Pb3O2 C Pb3O4 D Pb4O3

1 marks

Answer: C

This question in 0653/11 Oct/Nov 2007

20 Copper(II) oxide is mixed with solid Q. On heating the mixture, a reaction occurs and the limewater turns cloudy. copper(II) oxide and solid Q heat limewater What is solid Q? A carbon B iron C sulphur D zinc

1 marks

Answer: A

This question in 0653/11 Oct/Nov 2008

24 When a mixture of hydrogen and oxygen is ignited, an explosive reaction occurs and water is formed. Which terms describe this reaction? combustion redox 00 DW > «x O* & x \ x

1 marks

Answer: A

This question in 0653/11 Oct/Nov 2008

20 Which method is used to obtain iron from iron(III) oxide? A combustion B electrolysis C reduction D thermal decomposition

1 marks

Answer: C

This question in 0653/11 May/June 2010

24 What happens to a piece of magnesium when it burns in air? A oxidation and combustion B oxidation and thermal decomposition C reduction and combustion D reduction and thermal decomposition

1 marks

Answer: A

This question in 0653/11 May/June 2010

21 Which method is used to obtain iron from iron(III) oxide? A combustion B electrolysis C reduction D thermal decomposition

1 marks

Answer: C

This question in 0653/12 May/June 2010

25 What happens to a piece of magnesium when it burns in air? A oxidation and combustion B oxidation and thermal decomposition C reduction and combustion D reduction and thermal decomposition

1 marks

Answer: A

This question in 0653/12 May/June 2010

21 Which method is used to obtain iron from iron(III) oxide? A combustion B electrolysis C reduction D thermal decomposition

1 marks

Answer: C

This question in 0653/13 May/June 2010

25 What happens to a piece of magnesium when it burns in air? A oxidation and combustion B oxidation and thermal decomposition C reduction and combustion D reduction and thermal decomposition

1 marks

Answer: A

This question in 0653/13 May/June 2010

21 Aluminium occurs as aluminium oxide in the ore bauxite. Which terms apply to the extraction of aluminium from aluminium oxide? electrolysis reduction A v v B v x Cc x v D x x

1 marks

Answer: A

This question in 0653/12 Oct/Nov 2010

19 Aluminium occurs as aluminium oxide in the ore bauxite. Which terms apply to the extraction of aluminium from aluminium oxide? electrolysis reduction A v v B v x Cc x v D x x

1 marks

Answer: A

This question in 0653/13 Oct/Nov 2010

23 Ethene burns as shown. C2H4(g) + 3O2(g) → 2CO2(g) + 2H2O(l) What happens to ethene in this reaction? A decomposition B neutralisation C oxidation D reduction

1 marks

Answer: C

This question in 0653/11 Oct/Nov 2011

24 Ethene burns as shown. C2H4(g) + 3O2(g) → 2CO2(g) + 2H2O(l) What happens to ethene in this reaction? A decomposition B neutralisation C oxidation D reduction

1 marks

Answer: C

This question in 0653/12 Oct/Nov 2011

22 Ethene burns as shown. C2H4(g) + 3O2(g) → 2CO2(g) + 2H2O(l) What happens to ethene in this reaction? A decomposition B neutralisation C oxidation D reduction

1 marks

Answer: C

This question in 0653/13 Oct/Nov 2011

17 The equations show some chemical reactions. 1 copper + oxygen → copper oxide 2 copper carbonate → copper oxide + carbon dioxide 3 copper oxide + carbon → copper dioxide + water In which equations has the underlined substance been reduced? A 1 only B 1 and 2 C 2 and 3 D 3 only

1 marks

This question in 0653/11 May/June 2012

24 Copper(II) oxide is mixed with a solid Q. On heating the mixture, a reaction occurs and the limewater turns milky. copper(II) oxide and solid Q heat limewater What is solid Q? A carbon B iron C sulfur D zinc

1 marks

This question in 0653/11 May/June 2012

17 Copper(II) oxide reacts as shown. CuO + H2 → Cu + H2O Which statement about the reaction is correct? A Both oxidation and reduction take place. B Copper(II) oxide is a reducing agent. C Copper(II) oxide is oxidised to copper. D Hydrogen is reduced to water.

1 marks

Answer: A

This question in 0653/12 May/June 2012

17 Copper(II) oxide reacts as shown. CuO + H2 → Cu + H2O Which statement about the reaction is correct? A Both oxidation and reduction take place. B Copper(II) oxide is a reducing agent. C Copper(II) oxide is oxidised to copper. D Hydrogen is reduced to water.

1 marks

Answer: A

This question in 0653/13 May/June 2012

27 Which equation shows the complete combustion of a hydrocarbon? A C2H4 + 2O2 → 2CO + 2H2O B C2H4 + 3O2 → 2CO2 + 2H2O C C2H6O + 2O2 → 2CO + 3H2O D C2H6O + 3O2 → 2CO2 + 3H2O

1 marks

Answer: B

This question in 0653/13 May/June 2012

27 Which method is used to extract copper from copper(II) oxide? A dissolving copper(II) oxide with hydrochloric acid and then filtering B dissolving copper(II) oxide in water and then filtering C heating the copper(II) oxide D heating the copper(II) oxide mixed with carbon

1 marks

Answer: D

This question in 0653/12 May/June 2013

24 The equation shows the reaction of copper oxide with carbon. 2CuO + C → 2Cu + CO2 In the reaction, the carbon is the ……1…… agent and is ……2…… during the reaction. Which words complete gaps 1 and 2? 1 2 A oxidising oxidised B oxidising reduced C reducing oxidised D reducing reduced

1 marks

Answer: C

This question in 0653/13 May/June 2013

23 Metal X reacts rapidly with cold water. Metal Y does not react with dilute hydrochloric acid. Metal Y is obtained from its oxide by heating with carbon. Which row shows the more reactive metal and the type of reaction which metal Y oxide undergoes when it is heated with carbon? more reactive metal type of reaction A X oxidation B X reduction C Y oxidation D Y reduction

1 marks

Answer: B

This question in 0653/12 Oct/Nov 2013

25 Magnesium can be used to extract iron from iron(III) oxide, Fe2O3 to give magnesium oxide and iron. The equation for the reaction is shown. 2Mg + Fe2O3 → Mg2O3 + 2Fe Why is magnesium used in this reaction? A It is less reactive than iron and oxidises iron(III) oxide. B It is less reactive than iron and reduces iron(III) oxide. C It is more reactive than iron and oxidises iron(III) oxide. D It is more reactive than iron and reduces iron(III) oxide.

1 marks

Answer: D

This question in 0653/11 May/June 2014

27 Magnesium can be used to extract iron from iron(III) oxide, Fe2O3 to give magnesium oxide and iron. The equation for the reaction is shown. 2Mg + Fe2O3 → Mg2O3 + 2Fe Why is magnesium used in this reaction? A It is less reactive than iron and oxidises iron(III) oxide. B It is less reactive than iron and reduces iron(III) oxide. C It is more reactive than iron and oxidises iron(III) oxide. D It is more reactive than iron and reduces iron(III) oxide.

1 marks

Answer: D

This question in 0653/13 May/June 2014

22 Iron(III) oxide, Fe2O3, reacts with carbon monoxide, CO, to produce iron and carbon dioxide. The equation for the reaction is Fe2O3 + 3CO → 2Fe + 3CO2 Which statement is not correct? A Carbon is neither oxidised nor reduced. B Carbon is oxidised. C Iron is reduced. D This is a redox reaction.

1 marks

Answer: A

This question in 0653/11 Oct/Nov 2014

21 Iron(III) oxide, Fe2O3, reacts with carbon monoxide, CO, to produce iron and carbon dioxide. The equation for the reaction is Fe2O3 + 3CO → 2Fe + 3CO2 Which statement is not correct? A Carbon is neither oxidised nor reduced. B Carbon is oxidised. C Iron is reduced. D This is a redox reaction.

1 marks

Answer: A

This question in 0653/12 Oct/Nov 2014

20 In the blast furnace, iron(III) oxide reacts with carbon forming iron and carbon monoxide. What happens to the iron(III) oxide? A It is oxidised by gaining oxygen. B It is oxidised by losing oxygen. C It is reduced by gaining oxygen. D It is reduced by losing oxygen.

1 marks

Answer: D

This question in 0653/11 May/June 2015

21 Magnesium reacts with carbon dioxide to give magnesium oxide and carbon. What happens to the magnesium? A It is oxidised by gaining oxygen. B It is oxidised by losing oxygen. C It is reduced by gaining oxygen. D It is reduced by losing oxygen.

1 marks

Answer: A

This question in 0653/12 May/June 2015

21 The following reactions occur in the blast furnace. reaction 1: iron oxide + carbon monoxide → iron + carbon dioxide reaction 2: iron oxide + carbon → iron + carbon monoxide Which two substances are oxidised in these reactions? A carbon and carbon monoxide B carbon monoxide and carbon dioxide C iron and carbon dioxide D iron and iron oxide

1 marks

Answer: A

This question in 0653/13 May/June 2015

20 Magnesium reacts with steam to form magnesium oxide and hydrogen gas. Mg + H2O → MgO + H2 Which statement is correct? A Hydrogen gas is reduced. B Magnesium is oxidised. C Magnesium is reduced. D Water is oxidised.

1 marks

Answer: B

This question in 0653/11 Oct/Nov 2015

19 Which statement describes a redox reaction? A An acid reacts with a base. B Only oxidation takes place. C Oxygen is transferred from one substance to another. D Two substances are both reduced.

1 marks

Answer: C

This question in 0653/11 May/June 2016

19 Carbon dioxide reacts with carbon. carbon dioxide + carbon → carbon monoxide Which row describes what happens to the carbon dioxide and to the carbon during the reaction? carbon dioxide carbon A oxidised oxidised B oxidised reduced C reduced oxidised D reduced reduced

1 marks

Answer: C

This question in 0653/12 May/June 2016

20 In which word equation is copper reduced? A anhydrous copper sulfate + water → hydrated copper sulfate B copper carbonate + hydrochloric acid → copper chloride + water + carbon dioxide C copper oxide + hydrogen → copper + water D copper + oxygen → copper oxide

1 marks

Answer: C

This question in 0653/11 May/June 2017

20 In which reactions is the underlined substance oxidised? 1 iron when it rusts 2 methane when it burns in air 3 copper oxide when it reacts with carbon A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

1 marks

Answer: B

This question in 0653/12 May/June 2017

20 In which reactions is the underlined substance oxidised? 1 iron when it rusts 2 methane when it burns in air 3 copper oxide when it reacts with carbon A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

1 marks

Answer: B

This question in 0653/13 May/June 2017

20 Carbon reacts with carbon dioxide at high temperatures. carbon + carbon dioxide → carbon monoxide Which statement about the reaction is correct? A Both carbon and carbon dioxide are oxidised. B Both carbon and carbon dioxide are reduced. C The carbon is oxidised and the carbon dioxide is reduced. D The carbon is reduced and the carbon dioxide is oxidised.

1 marks

Answer: C

This question in 0653/11 Oct/Nov 2017

20 The word equation for the reaction between hydrogen and copper oxide is shown. hydrogen + copper oxide → copper + water Which substance, shown in the word equation, is reduced in the reaction? A copper B copper oxide C hydrogen D water

1 marks

Answer: B

This question in 0653/12 Oct/Nov 2017

20 Copper is produced by heating copper oxide with carbon. The word equation for this reaction is shown. copper oxide + carbon → copper + carbon dioxide Which statement explains why this is a redox reaction? A Carbon dioxide contains oxygen. B Carbon is a solid and carbon dioxide is a gas. C Copper oxide is oxidised. D Copper oxide loses oxygen and carbon gains oxygen.

1 marks

Answer: D

This question in 0653/13 Oct/Nov 2017

21 The equation shows the reaction of copper oxide with carbon. copper oxide + carbon → copper + carbon dioxide In the reaction, the carbon is the ««1«« agent and is ««2«« during the reaction. Which words complete gaps 1 and 2? 1 2 A oxidising oxidised B oxidising reduced C reducing oxidised D reducing reduced

1 marks

Answer: C

This question in 0653/12 Feb/March 2018

21 Magnesium reacts with steam to form magnesium oxide and hydrogen gas. magnesium + water → magnesium oxide + hydrogen Which statement about this reaction is correct? A Hydrogen gas is reduced. B Magnesium is oxidised. C Magnesium is reduced. D Water is oxidised.

1 marks

Answer: B

This question in 0653/11 May/June 2018

21 Magnesium reacts with steam to form magnesium oxide and hydrogen gas. magnesium + water → magnesium oxide + hydrogen Which statement about this reaction is correct? A Hydrogen gas is reduced. B Magnesium is oxidised. C Magnesium is reduced. D Water is oxidised.

1 marks

Answer: B

This question in 0653/12 May/June 2018

21 Magnesium reacts with steam to form magnesium oxide and hydrogen gas. magnesium + water → magnesium oxide + hydrogen Which statement about this reaction is correct? A Hydrogen gas is reduced. B Magnesium is oxidised. C Magnesium is reduced. D Water is oxidised.

1 marks

Answer: B

This question in 0653/13 May/June 2018

20 Iron oxide reacts with carbon monoxide. The word equation for the reaction is: iron oxide + carbon monoxide → iron + carbon dioxide Which statement is not correct? A Carbon is neither oxidised nor reduced. B Carbon is oxidised. C Iron is reduced. D This is a redox reaction.

1 marks

Answer: A

This question in 0653/11 Oct/Nov 2018

21 Iron oxide reacts with carbon monoxide. The word equation for the reaction is: iron oxide + carbon monoxide → iron + carbon dioxide Which statement is not correct? A Carbon is neither oxidised nor reduced. B Carbon is oxidised. C Iron is reduced. D This is a redox reaction.

1 marks

Answer: A

This question in 0653/12 Oct/Nov 2018

21 Iron oxide reacts with carbon monoxide. The word equation for the reaction is: iron oxide + carbon monoxide → iron + carbon dioxide Which statement is not correct? A Carbon is neither oxidised nor reduced. B Carbon is oxidised. C Iron is reduced. D This is a redox reaction.

1 marks

Answer: A

This question in 0653/13 Oct/Nov 2018

19 When magnesium is heated with steam, a white solid and hydrogen gas are formed. What happens to the magnesium in this reaction? A It is neutralised. B It is oxidised. C It is reduced. D It is thermally decomposed.

1 marks

Answer: B

This question in 0653/12 Feb/March 2019

20 Methane reacts with copper oxide. The equation for the reaction is shown. 4CuO + CH4 → 4Cu + CO2 + 2H2O Which statement about this reaction is correct? A Carbon is reduced. B Copper oxide is oxidised. C It is a redox reaction. D Methane is reduced.

1 marks

Answer: C

This question in 0653/11 May/June 2019

20 The equations for two redox reactions are shown. 1 CO + CuO → Cu + CO2 2 C + CO2 → 2CO Which row is correct? substance being substance being reduced in reaction 1 oxidised in reaction 2 A CuO C B CO CO2 C CO C D CuO CO2

1 marks

Answer: A

This question in 0653/12 May/June 2019

20 When hydrogen gas is passed over heated lead oxide, lead and water are produced. lead oxide + hydrogen → lead + water Which substance is reduced during the reaction? A hydrogen B lead C lead oxide D water

1 marks

Answer: C

This question in 0653/13 May/June 2019

21 In which reaction is a metal oxide being reduced? A copper oxide + hydrochloric acid → copper chloride + water B iron(II) oxide + oxygen → iron(III) oxide C lead oxide + carbon → lead + carbon dioxide D zinc oxide + sulfuric acid → zinc sulfate + water

1 marks

Answer: C

This question in 0653/11 Oct/Nov 2019

25 Copper oxide reacts with carbon. The equation is shown. copper oxide + carbon → copper + carbon dioxide What is the role of carbon in this reaction? A It is a catalyst. B It is an electrolyte. C It neutralises the copper oxide. D It reduces the copper oxide.

1 marks

Answer: D

This question in 0653/12 Oct/Nov 2019

25 Copper oxide reacts with carbon. The equation is shown. copper oxide + carbon → copper + carbon dioxide What is the role of carbon in this reaction? A It is a catalyst. B It is an electrolyte. C It neutralises the copper oxide. D It reduces the copper oxide.

1 marks

Answer: D

This question in 0653/13 Oct/Nov 2019

19 The equation for the reaction of iron(III) oxide with aluminium is shown. Fe2O3 + 2Al → Al 2O3 + 2Fe What is oxidised during this reaction? A aluminium B aluminium oxide C iron D iron(III) oxide

1 marks

Answer: A

This question in 0653/12 Feb/March 2020

20 Magnesium reacts with zinc oxide to form magnesium oxide and zinc. Which substance is reduced in this reaction? A magnesium B magnesium oxide C zinc D zinc oxide

1 marks

Answer: D

This question in 0653/12 Oct/Nov 2020

19 Which equation represents a reaction in which oxidation and reduction occur? A CaCO3  CaO + CO2 B 2H2 + O2  2H2O C Na2CO3 + ZnSO4  Na2SO4 + ZnCO3 D NaOH + HCl  NaCl + H2O

1 marks

Answer: B

This question in 0653/12 Feb/March 2021

24 Which compound can oxidise carbon? A aluminium oxide B copper oxide C magnesium oxide D potassium oxide

1 marks

Answer: B

This question in 0653/12 May/June 2021

20 Carbon dioxide reacts with carbon. carbon dioxide + carbon  carbon monoxide Which row describes what happens to the carbon dioxide and to the carbon during the reaction? carbon dioxide carbon A oxidised oxidised B oxidised reduced C reduced oxidised D reduced reduced

1 marks

Answer: C

This question in 0653/12 Feb/March 2022

21 Carbon reacts with carbon dioxide at high temperatures. carbon + carbon dioxide  carbon monoxide Which statement about the reaction is correct? A Both carbon and carbon dioxide are oxidised. B Both carbon and carbon dioxide are reduced. C The carbon is oxidised and the carbon dioxide is reduced. D The carbon is reduced and the carbon dioxide is oxidised.

1 marks

Answer: C

This question in 0653/11 May/June 2022

21 Carbon reacts with carbon dioxide at high temperatures. carbon + carbon dioxide  carbon monoxide Which statement about the reaction is correct? A Both carbon and carbon dioxide are oxidised. B Both carbon and carbon dioxide are reduced. C The carbon is oxidised and the carbon dioxide is reduced. D The carbon is reduced and the carbon dioxide is oxidised.

1 marks

Answer: C

This question in 0653/12 May/June 2022

21 Carbon reacts with carbon dioxide at high temperatures. carbon + carbon dioxide  carbon monoxide Which statement about the reaction is correct? A Both carbon and carbon dioxide are oxidised. B Both carbon and carbon dioxide are reduced. C The carbon is oxidised and the carbon dioxide is reduced. D The carbon is reduced and the carbon dioxide is oxidised.

1 marks

Answer: C

This question in 0653/13 May/June 2022

19 Iron oxide reacts with carbon monoxide. The word equation for the reaction is shown. iron oxide + carbon monoxide  iron + carbon dioxide Which statement about this reaction is not correct? A Carbon monoxide is reduced. B Carbon monoxide is oxidised. C Iron oxide is reduced. D It is a redox reaction.

1 marks

Answer: A

This question in 0653/11 Oct/Nov 2022

19 Iron oxide reacts with carbon monoxide. The word equation for the reaction is shown. iron oxide + carbon monoxide  iron + carbon dioxide Which statement about this reaction is not correct? A Carbon monoxide is reduced. B Carbon monoxide is oxidised. C Iron oxide is reduced. D It is a redox reaction.

1 marks

Answer: A

This question in 0653/12 Oct/Nov 2022

19 Iron oxide reacts with carbon monoxide. The word equation for the reaction is shown. iron oxide + carbon monoxide  iron + carbon dioxide Which statement about this reaction is not correct? A Carbon monoxide is reduced. B Carbon monoxide is oxidised. C Iron oxide is reduced. D It is a redox reaction.

1 marks

Answer: A

This question in 0653/13 Oct/Nov 2022

18 Which statement describes a redox reaction? A An acid reacts with a base. B Only oxidation takes place. C Oxygen is transferred from one substance to another. D Two substances are both reduced.

1 marks

Answer: C

This question in 0653/12 Feb/March 2023

20 In which chemical reaction is copper reduced? A anhydrous copper sulfate + water  hydrated copper sulfate B copper carbonate + hydrochloric acid  copper chloride + water + carbon dioxide C copper oxide + hydrogen  copper + water D copper + oxygen  copper oxide

1 marks

Answer: C

This question in 0653/11 May/June 2023

25 Copper oxide and excess carbon are mixed together. The mass before heating is 12.2 g. The mixture is heated strongly and allowed to cool. The mass after heating is 10.4 g. Why does the mass change? A Carbon forms carbon dioxide which then combines with the copper oxide. B Carbon reduces the copper oxide and leaves the test-tube as carbon dioxide. C Copper oxide loses oxygen, turns into copper and the carbon remains unchanged. D Carbon oxidises the copper oxide and leaves the test-tube as carbon dioxide.

1 marks

Answer: B

This question in 0653/11 May/June 2023

20 In which reactions is the underlined substance oxidised? 1 iron when it rusts 2 methane when it burns in air 3 copper oxide when it reacts with carbon A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

1 marks

Answer: B

This question in 0653/12 May/June 2023

21 The word equation for the reaction between hydrogen and copper oxide is shown. hydrogen + copper oxide → copper + water Which substance, shown in the word equation, is reduced in the reaction? A copper B copper oxide C hydrogen D water

1 marks

Answer: B

This question in 0653/13 May/June 2023

19 Magnesium ribbon reacts with steam. The equation for the reaction is shown. Mg + H2O  MgO + H2 Which substance is being reduced in this reaction? A H2 B H2O C Mg D MgO

1 marks

Answer: B

This question in 0653/11 Oct/Nov 2023

19 Iron is extracted from its ore using carbon monoxide. The word equation is shown. iron(III) oxide + carbon monoxide  iron + carbon dioxide Which statement is correct? A Carbon monoxide is oxidised by gaining oxygen. B Carbon monoxide is reduced by losing oxygen. C Iron(III) oxide is oxidised by losing oxygen. D Iron(III) oxide is reduced by gaining oxygen.

1 marks

Answer: A

This question in 0653/12 Oct/Nov 2023

19 Iron is extracted from its ore using carbon monoxide. The word equation is shown. iron(III) oxide + carbon monoxide  iron + carbon dioxide Which statement is correct? A Carbon monoxide is oxidised by gaining oxygen. B Carbon monoxide is reduced by losing oxygen. C Iron(III) oxide is oxidised by losing oxygen. D Iron(III) oxide is reduced by gaining oxygen.

1 marks

Answer: A

This question in 0653/13 Oct/Nov 2023

19 The equation for the reaction of sodium with oxygen is shown. 4Na + O2  2Na2O Which process is involved in this reaction? A decomposition B oxidation C neutralisation D precipitation

1 marks

Answer: B

This question in 0653/12 Feb/March 2024

19 Four equations for reactions involving oxidation and reduction are listed. 1 CO2 + 2Mg  C + 2MgO 2 H2 + PbO  Pb + H2O 3 2Cu + O2  2CuO 4 CO + Fe2O3  2FeO + CO2 Which statement is correct? A In reaction 1, the Mg is being reduced. B In reaction 2, the PbO is being oxidised. C In reaction 3, the CuO is being oxidised. D In reaction 4, the Fe2O3 is being reduced.

1 marks

Answer: D

This question in 0653/11 May/June 2024

21 What is a reduction process? A the combustion of a fuel B the thermal decomposition of calcium carbonate C the extraction of copper from copper oxide D the reaction between an acid and an alkali

1 marks

Answer: C

This question in 0653/12 May/June 2024

21 When iron rusts, iron(III) oxide is formed. What is the meaning of (III) in iron(III) oxide? A It is the number of iron ions in the formula for iron(III) oxide. B It is the ratio of iron ions to oxygen ions. C It is the oxidation state of iron ions in iron(III) oxide. D It is the pH of iron ions in iron(III) oxide.

1 marks

Answer: C

This question in 0653/13 May/June 2024

19 Copper oxide reacts with hydrogen to form copper and water. The equation for this reaction is shown. CuO + H2  Cu + H2O Which substance is reduced in this reaction? A Cu B CuO C H2 D H2O

1 marks

Answer: B

This question in 0653/11 Oct/Nov 2024

19 Which type of reaction occurs when iron is obtained from its oxide using carbon? A combustion B neutralisation C electrolysis D reduction

1 marks

Answer: D

This question in 0653/12 Oct/Nov 2024

19 Which type of reaction occurs when iron is obtained from its oxide using carbon? A combustion B neutralisation C electrolysis D reduction

1 marks

Answer: D

This question in 0653/13 Oct/Nov 2024

23 Which row explains why carbon is used to extract copper from copper oxide and identifies the type of reaction that occurs during the extraction? explanation type of reaction A carbon is more reactive than copper redox B carbon is more reactive than copper thermal decomposition C carbon is less reactive than copper redox D carbon is less reactive than copper thermal decomposition

1 marks

Answer: A

This question in 0653/13 Oct/Nov 2024

21 Which description explains why a reaction involves reduction? A mass decreases B oxygen is lost C pH decreases D temperature decreases

1 marks

Answer: B

This question in 0653/11 May/June 2025

22 Which statement describes what happens during reduction? A An element gains oxygen. B A compound gains oxygen. C A compound loses oxygen. D A mixture of elements loses oxygen.

1 marks

Answer: C

This question in 0653/12 May/June 2025

25 In the blast furnace, iron(III) oxide reacts with carbon monoxide to form iron. What happens to the iron(III) oxide? A It is oxidised by gaining oxygen. B It is oxidised by losing oxygen. C It is reduced by gaining oxygen. D It is reduced by losing oxygen.

1 marks

Answer: D

This question in 0653/13 May/June 2025