Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Section
Reaction with metals
18 practice questions
Practice questions
11–18 of 18
Question 11
4 marks · Normal
Answer and see the solution →The table below shows the reaction of four different carboxylic acids with magnesium ribbon. In each case, 10 cm³ of acid at the same concentration is used. The time taken for the reaction to stop is measured:
Carboxylic Acid Time taken for reaction to stop / s methanoic acid 110 ethanoic acid 98 propanoic acid 99 butanoic acid 112 (a)[1 mark]Which acid reacts fastest with magnesium ribbon? Support your answer using data.
(b)[1 mark]Suggest why the reactions do not all take the same time, even though the acids are at the same concentration.
(c)[1 mark]Write the formula for the salt formed when butanoic acid reacts with magnesium.
(d)[1 mark]State one safety precaution when carrying out these reactions.
Question 12
1 mark · Normal
Answer and check →Which statement best describes a weak acid such as ethanoic acid?
- A.It ionises completely in water.
- B.It ionises partially in water.
- C.It does not ionise in water.
- D.It is less dense than water.
Question 13
2 marks · Normal
Answer and see the solution →Give the name and the molecular formula of the carboxylic acid with three carbon atoms.
Question 14
4 marks · Normal
Answer and see the solution →A student adds blue litmus paper to a solution of butanoic acid then tests its pH before and after adding sodium carbonate. Answer the following questions.
(a)[1 mark]State what is observed when the blue litmus paper is placed in butanoic acid.
(b)[1 mark]Give a likely pH value for butanoic acid.
(c)[1 mark]State what you would observe after adding sodium carbonate to the butanoic acid.
(d)[1 mark]Explain why the pH of the solution increases after adding sodium carbonate.
Question 15
3 marks · Normal
Answer and see the solution →A student reacts 4.8 g of magnesium ribbon with excess ethanoic acid. Magnesium reacts with ethanoic acid as shown:
Calculate the maximum volume of hydrogen gas produced at room temperature and pressure (rtp), assuming 1 mole of gas occupies 24 dm³. (Relative atomic mass: Mg = 24)
Question 16
2 marks · Hard
Answer and see the solution →Butanoic acid and hydrochloric acid have the same concentration. Explain why the pH of butanoic acid is higher than that of hydrochloric acid.
Question 17
5 marks · Hard
Answer and see the solution →A solution of ethanoic acid is reacted with calcium carbonate (CaCO₃) powder in a test-tube.
(a)[1 mark]State one observation you would make during the reaction.
(b)[2 marks]Write a balanced symbol equation for the reaction.
(c)[1 mark]Name the salt formed.
(d)[1 mark]Ethanoic acid reacts more slowly than hydrochloric acid of the same concentration. Explain why.
Question 18
2 marks · Hard
Answer and see the solution →Describe two ways you could show that propanoic acid is a weak acid.