Exothermic and endothermic reactions — Paper 2 · IGCSE Sciences - Co-ordinated (9-1) 0973

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 0973/21 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 0973/22 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 0973/21 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 0973/21 Oct/Nov 2020

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 0973/21 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 0973/22 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 0973/22 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 0973/21 Oct/Nov 2022

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 0973/21 Oct/Nov 2023

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 0973/21 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 0973/22 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 0973/21 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 0973/21 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 0973/22 May/June 2025