Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Section
Making ethanol by the hydration of ethene
19 practice questions
Practice questions
11–19 of 19
Question 11
3 marks · Normal
Answer and see the solution →During the hydration of ethene, only 15% of ethene is converted to ethanol in one pass through the reactor. 1000 mol of ethene are used.
Calculate:
(a)[1 mark]The number of moles of ethene that react.
(b)[1 mark]The number of moles of ethene unreacted after one pass.
(c)[1 mark]Explain, in one sentence, why the unreacted ethene is recycled in the process.
Question 12
4 marks · Normal
Answer and see the solution →The table below shows different industrial runs for the hydration of ethene, with the corresponding conditions and yields.
Run Temperature (°C) Pressure (atm) Catalyst Yield of ethanol (%) A 270 60 phosphoric acid 70 B 300 65 phosphoric acid 81 C 325 70 phosphoric acid 84 D 350 55 phosphoric acid 77 (a)[1 mark]Identify the run with the highest ethanol yield.
(b)[1 mark]State the temperature and pressure for this best-yield run.
(c)[1 mark]Describe how increasing temperature affected yield between runs A, B and C.
(d)[1 mark]Suggest one reason why the yield in run D is lower than in run C, even though the temperature is higher.
Question 13
1 mark · Normal
Answer and check →Why is unreacted ethene recycled in the hydration process for making ethanol?
- A.To save costs by heating less gas
- B.To maximise the total yield of ethanol from starting material
- C.To produce a more concentrated ethanol solution
- D.To use less catalyst in the process
Question 14
2 marks · Normal
Answer and see the solution →Give the names of the two reactants required to make ethanol by the hydration of ethene. Write the chemical formula for each.
Question 15
4 marks · Normal
Answer and see the solution →(a)[2 marks]List the three main conditions (temperature, pressure, and catalyst) used for the industrial hydration of ethene to make ethanol.
(b)[1 mark]State why a phosphoric acid catalyst is used in this process.
(c)[1 mark]Explain why the pressure used is not even higher than 70 atmospheres, even though increasing pressure can raise yield.
Question 16
3 marks · Normal
Answer and see the solution →Ethanol can be made from ethene by hydration.
(a)[1 mark]State the word equation for the hydration of ethene to produce ethanol.
(b)[2 marks]Write the balanced symbol equation for this reaction. Include physical states.
Question 17
2 marks · Hard
Answer and see the solution →State the temperature and pressure conditions required for the industrial hydration of ethene to make ethanol.
Question 18
5 marks · Hard
Answer and see the solution →In the industrial process to make ethanol from ethene, only some of the ethene reacts in a single pass through the reactor.
(a)[2 marks]Explain what happens to the ethene that does not react during one pass through the reactor.
(b)[2 marks]Describe one advantage of recycling the unreacted ethene in this process.
(c)[1 mark]Suggest what effect not recycling unreacted ethene would have on the overall yield of ethanol.
Question 19
2 marks · Hard
Answer and see the solution →Give the word equation and the balanced symbol equation for making ethanol by hydration of ethene.