Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Chapter
Esters
68 practice questions
Topics covered
Practice questions
21–28 of 28 · Normal
Question 21
2 marks · Normal
Answer and see the solution →State two reasons why sodium carbonate solution is added at the end of the ester preparation process.
Question 22
4 marks · Normal
Answer and see the solution →A chemistry student mixes methanol and butanoic acid to make an ester using the laboratory method.
(a)[1 mark]Name the ester formed.
(b)[2 marks]Briefly outline the apparatus set-up used for heating the reaction mixture safely.
(c)[1 mark]How would you test for the presence of the ester after the reaction is complete?
Question 23
3 marks · Normal
Answer and see the solution →A student prepares an ester in the lab by reacting 1.0 cm³ of propanoic acid (density = 1.01 g/cm³, molar mass = 74 g/mol) with an excess of methanol in the presence of a few drops of concentrated sulfuric acid. After the reaction, they transfer the contents to water to isolate the ester layer.
Calculate the maximum mass of methyl propanoate that could be formed from the propanoic acid used.
Question 24
3 marks · Normal
Answer and see the solution →Describe how esters can be made and separated in the laboratory. In your answer, explain the roles of each of the following:
(a) concentrated sulfuric acid,
(b) the hot water bath,
(c) adding sodium carbonate solution after the reaction.
Question 25
6 marks · Normal
Answer and see the solution →Butanol and ethanoic acid are used together in a laboratory to produce an ester. Answer the following questions about this reaction and the practical steps involved.
(a)[1 mark]Name the ester formed in this reaction.
(b)[2 marks]Draw the structural formula for the ester you named in part (a).
(c)[1 mark]State the name of the catalyst used during this esterification reaction.
(d)[2 marks]Describe one step you would take in the laboratory to make the smell of the ester easier to detect after the reaction is complete.
Question 26
6 marks · Normal
Answer and see the solution →A student wants to prepare methyl propanoate in the laboratory using appropriate organic starting materials.
(a)[2 marks]Identify the alcohol and the carboxylic acid required to make methyl propanoate.
(b)[2 marks]Draw the structural formula for methyl propanoate.
(c)[2 marks]Describe briefly, in two steps, how a small sample of methyl propanoate can be prepared and the smell detected during a school practical.
Question 27
6 marks · Normal
Answer and see the solution →A group of students carried out an experiment to produce an ester from ethanol and propanoic acid. They left the product to stand after completing the practical.
(a)[2 marks]Explain how the students could confirm that an ester had formed, even if the reactants and product are colourless.
(b)[1 mark]Ethyl propanoate is an ester. Give the name of the alcohol used to manufacture this ester.
(c)[1 mark]The mixture was poured into a beaker containing sodium carbonate solution. Suggest a reason for this step.
(d)[2 marks]Explain why small esters are easy to separate from the reaction mixture compared to the carboxylic acid and alcohol used.
Question 28
6 marks · Normal
Answer and see the solution →Propanoic acid reacts with ethanol to form an ester. You are given 1.5 cm³ of propanoic acid (density = 1.00 g/cm³) and an excess of ethanol.
(a)[3 marks]Draw the structural formula of the ester formed in this reaction and name the ester.
(b)[2 marks]In a laboratory experiment, you attempt to prepare the ester in part (a). (i) Calculate the maximum mass of the ester that could be formed from 1.5 cm³ of propanoic acid (M_r of propanoic acid = 74, M_r of the ester = 102).
(c)[1 mark]Describe how you could separate and identify the smell of the ester after the reaction, referring to the laboratory method and your answer to part (b).