IGCSE CHEMICAL ENERGETICS MCQ PRACTICE (with the answer key)

1 The energy level diagram for the reaction between sodium hydrogen carbonate and dilute hydrochloric acid is shown.

     

Which row correctly describes the type of reaction and the energy of the reactants and products?

       

2. The energy level diagram for the reaction between magnesium and hydrochloric acid is shown. Which statement about the reaction is not correct?

      

A Energy is given out during the reaction.
B The products are at a lower energy level than the reactants.
C The reaction is endothermic.
D The temperature increases during the reaction.

3. The energy level diagram shows the energy of the reactants and products in a chemical reaction.

       

Which row correctly describes the energy change and the type of reaction shown?

4. Which reaction is endothermic?
A acid neutralising alkali causing a temperature increase
B adding magnesium to hydrochloric acid
C calcium carbonate decomposing when heated
D combustion of fossil fuels

5. Solid hydrated sodium carbonate was added to solid citric acid.
The mixture was stirred and the temperature recorded every 10 seconds. The results are shown on the graph:

Which row describes the reaction?

6. Which row correctly describes whether the reaction is exothermic or endothermic?

7 A metal reacts with an aqueous solution.

The graph shows the temperature before, during and after the reaction.

 

Which row describes the reaction?

8. The diagrams show four chemical reactions.

Which reaction is endothermic?

9. Limestone can be changed into slaked lime in two chemical reactions.

                  
    1 When limestone, CaCO3, is heated it decomposes into lime, CaO.

    2 Water is slowly dripped onto the cooled lime. The lime appears to expand and steam is  

      produced. Slaked lime, Ca(OH)2, is formed.

 Which row shows the correct description of each of the chemical reactions?

10. Which statements about exothermic and endothermic reactions are correct?


     1 During an exothermic reaction, heat is given out.

     2 The temperature of an endothermic reaction goes up because heat is taken in.

     3 Burning methane in the air is an exothermic reaction.

      A 1, 2        B 1 and 2 only          C 1 and 3 only         D 2 and 3 only

 11. What occurs when a fuel burns?

12. Some reactions are endothermic.
How does the temperature and energy change in an endothermic reaction?

13. Two chemical processes are described below.

● In the combustion of methane, energy is ......1...... .

● In the electrolysis of molten lead(II) bromide, energy is ......2...... .

Which words correctly complete gaps 1 and 2?

 

14. Solutions of two chemicals are mixed.

A reaction occurs and the temperature change is measured. Which statement is correct?

A  If the reaction is endothermic, the temperature decreases and energy is taken in.

B  If the reaction is endothermic, the temperature increases and energy is given out.

C  If the reaction is exothermic, the temperature decreases and energy is given out.

D  If the reaction is exothermic, the temperature increases and energy is taken in.

15. When anhydrous copper(II) sulfate is added to water a solution is formed and heat is given out

Which row correctly shows the temperature change and the type of reaction taking place?

16. When ammonium nitrate is added to water the temperature of the water decreases.
The ammonium nitrate can be recovered by evaporating the water added. Which explains these observations?
A The ammonium nitrate dissolves in the water and the process is endothermic.
B The ammonium nitrate reacts with the water and the process is endothermic.
C The ammonium nitrate dissolves in the water and the process is exothermic.
D The ammonium nitrate reacts with the water and the process is exothermic.

17. Some white anhydrous copper(II) sulfate powder is put into a beaker of water and stirred.
What would show that the process was exothermic?
A A blue solution is formed.
B The beaker feels cooler.
C The beaker feels warmer.
D The powder dissolves in the water.

18. The diagrams show the difference in energies of the reactants and products in two types of reaction.

Which diagram and which type of energy change apply to a fuel burning in air?

19. The diagram shows a match.

By striking the match, a chemical reaction takes place. Which statements about the chemical reaction are correct?

20. A diagram for the energy change during an exothermic reaction is shown

For which reactions would this be an appropriate diagram?

        1 CH4 + 2O2 → CO2 + 2H2O

        2 2H2 + O2 → 2H2O

        3 C + O2 → CO2

A none of them
B 1 and 2 only
C 2 and 3 only
D all of them

21. The diagram shows the reaction between zinc oxide and dilute hydrochloric acid.

Which terms describe the reaction?

22. Acetylene, C2H2, is a hydrocarbon. When acetylene and oxygen react, the hot flame produced can be used to weld steel. Which statement is correct?

A Acetylene and oxygen react exothermically.
B Acetylene is saturated.
C Oxygen and steel react endothermically.
D Oxygen is a gaseous fuel.

23. Which fuel needs oxygen in order to produce heat energy and which type of reaction produces the energy?

24. Some reactions are listed.

        methane + oxygen → carbon dioxide + water

        sodium + water → sodium hydroxide + hydrogen

        magnesium + hydrochloric acid → magnesium chloride + hydrogen 

Which word correctly describes all of these reactions?

A combustion

B endothermic

C exothermic

D neutralisation

25. Which is an endothermic process?

A      burning hydrogen

B      distilling petroleum

C      reacting potassium with water

D      using petrol in a motor car engine

26. The diagrams show some pieces of laboratory equipment.

Which equipment is needed to find out whether dissolving salt in water is an endothermic process?

A 1 only      B 1 and 3       C 2 and 3        D 3 only

27.  Clouds are formed when water vapour evaporates from the sea.

What is the energy change and what name is given to the type of change when water evaporates?

28. Which process is not exothermic?

29. When an acid is added to an alkali the temperature rises.

Which words describe this reaction?

A  decomposition and endothermic

B decomposition and exothermic

C  neutralisation and endothermic

D  neutralisation and exothermic

30. Which diagram shows a process in which an endothermic change is taking place?

DOWNLOAD ANSWER KEY: [click here]