Exothermic and endothermic reactions — Paper 2 · IGCSE Sciences - Co-ordinated (Double) 0654

16 Hand warmers keep hands warm on a cold day. Which statement describes how hand warmers work? A An endothermic process occurs in which chemical energy is transformed into thermal energy. B An endothermic process occurs in which thermal energy is transformed into chemical energy. C An exothermic process occurs in which chemical energy is transformed into thermal energy. D An exothermic process occurs in which thermal energy is transformed into chemical energy.

1 marks

Answer: C

This question in 0654/22 Oct/Nov 2017

16 Dilute hydrochloric acid is added to aqueous sodium hydroxide in a non-insulated beaker. The temperature of the mixture increases. Which statement is not correct? A The reaction is exothermic. B There is a reduction in the amount of chemical energy. C There is an increase in the amount of thermal energy. D There is no energy loss from the mixture.

1 marks

Answer: D

This question in 0654/23 Oct/Nov 2017

19 Methane is used as a fuel. Which row describes the temperature change and the type of reaction when methane burns? temperature type of change reaction A decrease endothermic B decrease exothermic C increase endothermic D increase exothermic

1 marks

Answer: D

This question in 0654/21 Oct/Nov 2018

20 Lime is manufactured from calcium carbonate. Which type of reaction is involved in this process? A endothermic B neutralisation C precipitation D reduction

1 marks

Answer: A

This question in 0654/22 Oct/Nov 2018

19 Solid sodium hydroxide reacts with dilute hydrochloric acid. Which change shows that the reaction is exothermic? A A gas is produced. B The mass increases. C The pH increases. D The temperature increases.

1 marks

Answer: D

This question in 0654/23 Oct/Nov 2018

18 An acid is added to an alkali until the final solution is just neutral. The reaction is exothermic. Which graph shows how the temperature changes as the acid is being added to the alkali? A B start start temperature temperature 0 volume of acid 0 volume of acid C D start start temperature temperature 0 volume of acid 0 volume of acid

1 marks

Answer: C

This question in 0654/21 May/June 2019

19 An acid is added to an alkali until the final solution is just neutral. The reaction is exothermic. Which graph shows how the temperature changes as the acid is being added to the alkali? A B start start temperature temperature 0 volume of acid 0 volume of acid C D start start temperature temperature 0 volume of acid 0 volume of acid

1 marks

Answer: C

This question in 0654/22 May/June 2019

19 An acid is added to an alkali until the final solution is just neutral. The reaction is exothermic. Which graph shows how the temperature changes as the acid is being added to the alkali? A B start start temperature temperature 0 volume of acid 0 volume of acid C D start start temperature temperature 0 volume of acid 0 volume of acid

1 marks

Answer: C

This question in 0654/23 May/June 2019

19 Which statement describes what happens when ethanol burns? A Chemical energy transfers to thermal energy in an endothermic reaction. B Chemical energy transfers to thermal energy in an exothermic reaction. C Thermal energy transfers to chemical energy in an endothermic reaction. D Thermal energy transfers to chemical energy in an exothermic reaction.

1 marks

Answer: B

This question in 0654/21 Oct/Nov 2019

17 Which statement describes an endothermic reaction? A The products have less energy than the reactants and the temperature decreases. B The products have less energy than the reactants and the temperature increases. C The products have more energy than the reactants and the temperature decreases. D The products have more energy than the reactants and the temperature increases.

1 marks

Answer: C

This question in 0654/21 Oct/Nov 2020

17 Which statement describes an exothermic reaction? A The products have less energy than the reactants and there is a decrease in temperature. B The products have less energy than the reactants and there is an increase in temperature. C The products have more energy than the reactants and there is a decrease in temperature. D The products have more energy than the reactants and there is an increase in temperature.

1 marks

Answer: B

This question in 0654/22 Oct/Nov 2020

17 Which process is exothermic? A boiling water B cracking a long chain alkene C decomposition of limestone D identification of hydrogen using a lit splint

1 marks

Answer: D

This question in 0654/23 Oct/Nov 2020

18 The diagram shows the energy change for the reactions between hydrogen and the halogens. The reaction is H2 + X2  2HX. The size of the energy change is different for each halogen. H2 + X2 energy change energy 2HX progress of reaction The diagram shows that the reactions are ……1…… . The most reactive halogen is ……2…… and therefore the energy change for this element is ……3…… . Which words complete gaps 1, 2 and 3? 1 2 3 A endothermic fluorine least B endothermic iodine least C exothermic fluorine greatest D exothermic iodine greatest

1 marks

Answer: C

This question in 0654/22 Feb/March 2021

18 An energy level diagram for a chemical reaction is shown. products energy reactants progress of reaction Which row describes the energy change and the type of reaction? energy change type of reaction A energy is given out to the surroundings endothermic B energy is given out to the surroundings exothermic C energy is taken in from the surroundings endothermic D energy is taken in from the surroundings exothermic

1 marks

Answer: C

This question in 0654/21 May/June 2021

18 An energy level diagram for a reaction is shown. Which arrow shows the overall energy change for the reaction? B products energy A C D reactants progress of reaction

1 marks

Answer: D

This question in 0654/22 May/June 2021

24 Which reaction in the Contact process is endothermic? A S + O2  SO2 B 2SO2 + O2  2SO3 C SO3 + H2SO4  H2S2O7 D H2S2O7 + H2O  2H2SO4

1 marks

Answer: B

This question in 0654/22 May/June 2022

19 Which statement about energy changes in chemical reactions is correct? A Activation energy is the maximum energy required by the reactants for a reaction to occur. B Bond forming is an endothermic process. C In an exothermic reaction, the energy level of the reactants is higher than the energy level of the products. D Increasing temperature increases the minimum energy required by the reactants for a reaction to occur.

1 marks

Answer: C

This question in 0654/21 Oct/Nov 2022

19 Which row describes the type of energy change and the energy transfer when bonds are broken during a chemical reaction? type of change energy transfer A endothermic given out B endothermic taken in C exothermic given out D exothermic taken in

1 marks

Answer: B

This question in 0654/22 Oct/Nov 2022

19 Which energy level diagram correctly represents an exothermic reaction? A B energy energy Ea Ea progress of progress of reaction reaction key C D Ea = activation energy Ea energy energy Ea progress of progress of reaction reaction

1 marks

Answer: D

This question in 0654/23 Oct/Nov 2022

18 Which process is exothermic? A boiling water B cracking a long chain alkane C decomposition of limestone D identification of hydrogen using a lighted splint

1 marks

Answer: D

This question in 0654/22 Feb/March 2023

18 Which statement about chemical reactions is correct? A Endothermic reactions result in a temperature decrease. B Endothermic reactions result in a temperature increase. C Exothermic reactions always produce a large temperature rise. D Exothermic reactions always produce a small temperature rise.

1 marks

Answer: A

This question in 0654/23 May/June 2023

18 The temperature of solution Q is 21 C. The temperature of solution P is 24 C. The two solutions are mixed. The temperature of the mixture is 31 C. Which statement is correct? A An endothermic reaction occurs and the reacting chemicals gain energy. B An endothermic reaction occurs and the reacting chemicals lose energy. C An exothermic reaction occurs and the reacting chemicals gain energy. D An exothermic reaction occurs and the reacting chemicals lose energy.

1 marks

Answer: D

This question in 0654/21 Oct/Nov 2023

18 Ultraviolet light causes a chlorine molecule to break down to form two chlorine atoms. The equation for the reaction is shown. Cl 2(g)  2Cl (g) What is the energy level diagram for this reaction? A B Cl 2(g) Cl 2(g) exothermic endothermic energy reaction energy reaction 2Cl (g) 2Cl (g) reaction progress reaction progress C D 2Cl (g) 2Cl (g) exothermic endothermic energy energy reaction reaction Cl 2(g) Cl 2(g) reaction progress reaction progress

1 marks

Answer: D

This question in 0654/22 Feb/March 2024

20 A piece of sodium is added to water. Which row shows the type of reaction and the energy level diagram for the reaction? type of reaction energy level diagram 2NaOH + H2 energy A endothermic 2Na + 2H2O progress of reaction 2Na + 2H2O energy B endothermic 2NaOH + H2 progress of reaction 2NaOH + H2 energy C exothermic 2Na + 2H2O progress of reaction 2Na + 2H2O energy D exothermic 2NaOH + H2 progress of reaction

1 marks

Answer: D

This question in 0654/21 May/June 2024

18 The energy level diagram for a reaction is shown. products energy reactants progress of reaction The diagram represents an … 1 … reaction. Heat is … 2 … during this reaction. Which words complete gaps 1 and 2? 1 2 A endothermic given out B endothermic taken in C exothermic given out D exothermic taken in

1 marks

Answer: B

This question in 0654/22 May/June 2024

19 When a match burns, heat and light energy are produced. Which row describes the type of change and the type of reaction taking place? type of change type of reaction A chemical endothermic B chemical exothermic C physical endothermic D physical exothermic

1 marks

Answer: B

This question in 0654/21 Oct/Nov 2024

17 What describes an endothermic reaction? A a reaction in which all the bonds in all the reactants are broken B a reaction in which energy is released to the surroundings C a reaction which goes to completion D a reaction in which energy is taken in from the surroundings

1 marks

Answer: D

This question in 0654/22 Oct/Nov 2024

19 What happens when an acid reacts with an alkali? A Neutralisation takes place and the temperature falls. B Neutralisation takes place and the temperature rises. C Reduction takes place and the temperature falls. D Reduction takes place and the temperature rises.

1 marks

Answer: B

This question in 0654/22 Oct/Nov 2024

17 Which energy level diagram shows the activation energy for an exothermic reaction? A B activation energy product product energy energy activation energy reactants reactants progress of reaction progress of reaction C D activation reactants energy reactants energy energy activation energy product product progress of reaction progress of reaction

1 marks

Answer: C

This question in 0654/23 Oct/Nov 2024

22 A reaction pathway diagram for a reaction is shown. 400 300 products energy 200 kJ / mol reactants 100 0 progress of reaction What is the value of the activation energy for this reaction? A 100 kJ / mol B 150 kJ / mol C 250 kJ / mol D 350 kJ / mol

1 marks

Answer: C

This question in 0654/21 May/June 2025

16 The table shows the initial and final temperatures of four different reactions. initial temperature final temperature reaction / °C / °C 1 20 20 2 20 30 3 25 20 4 25 30 Which reactions are exothermic? A 1 and 3 B 2 and 3 C 2 and 4 D 3 and 4

1 marks

Answer: C

This question in 0654/22 May/June 2025

18 A reaction pathway diagram for a reaction is shown. reactants energy products progress of reaction Which reactions have a reaction pathway diagram like the one shown? 1 C + O2  CO2 2 CaCO3  CaO + CO2 3 2C3H6 + 9O2  6CO2 + 6H2O 4 H2O(l)  H2O(g) A 1 and 2 B 1 and 3 C 2 and 4 D 3 and 4

1 marks

Answer: B

This question in 0654/23 May/June 2025

22 When magnesium reacts with dilute hydrochloric acid, the temperature of the mixture increases. Which statement about this reaction is correct? A It is endothermic as thermal energy is taken in from the surroundings. B It is endothermic as thermal energy is transferred to the surroundings. C It is exothermic as thermal energy is taken in from the surroundings. D It is exothermic as thermal energy is transferred to the surroundings.

1 marks

Answer: D

This question in 0654/22 Oct/Nov 2025

15 Magnesium reacts with dilute hydrochloric acid. During the reaction, the reaction mixture becomes warm. What is the reaction pathway diagram for this reaction? A B activation energy products products energy energy activation energy reactants reactants progress of reaction progress of reaction C D activation reactants energy reactants energy energy activation energy products products progress of reaction progress of reaction

1 marks

Answer: C

This question in 0654/23 Oct/Nov 2025