Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Unit
Organic Chemistry
785 practice questions
Topics covered
Practice questions
221–230 of 335 · Normal
Question 221
2 marks · Normal
Answer and see the solution →State one advantage and one disadvantage of producing ethanol by fermentation compared to the hydration of ethene.
Question 222
4 marks · Normal
Answer and see the solution →The table below gives some information about two industrial methods for making ethanol.
Fermentation Hydration of Ethene Batch process Continuous process Sugar beet or corn used Ethene from crude oil used Slower (days) Faster (hours) Low temperature and pressure High temperature and pressure (a)[1 mark]Give one reason why some countries prefer making ethanol by fermentation.
(b)[1 mark]State one process feature that makes hydration of ethene more efficient than fermentation.
(c)[2 marks]Explain why ethanol from fermentation needs further processing before it can be used as a chemical feedstock.
Question 223
3 marks · Normal
Answer and see the solution →A chemical company can produce ethanol by either fermentation or hydration of ethene.
(a)[1 mark]The hydration of ethene gives ethanol that is 99% pure by mass. If 5.0 tonnes of ethanol are made, calculate the mass of pure ethanol obtained.
(b)[1 mark]Fermentation produces ethanol that is only 90% pure by mass from the same 5.0 tonnes. Calculate the mass of pure ethanol produced.
(c)[1 mark]Based on your answers, explain one advantage of the hydration method.
Question 224
3 marks · Normal
Answer and see the solution →Ethanol can be produced industrially by fermentation or by hydration of ethene with steam.
(a)[2 marks]Explain why the hydration of ethene is not considered a sustainable process in the long term.
(b)[1 mark]State one environmental advantage of using fermentation instead.
Question 225
2 marks · Normal
Answer and see the solution →State one advantage and one disadvantage of producing ethanol by hydration of ethene rather than by fermentation.
Question 226
4 marks · Normal
Answer and see the solution →Ethanol can be produced industrially by fermentation or by hydration of ethene.
(a)[1 mark]State the raw material used in fermentation to produce ethanol.
(b)[1 mark]State one condition needed for the hydration of ethene to produce ethanol.
(c)[1 mark]Explain one reason why the production of ethanol by fermentation is considered more sustainable than hydration of ethene.
(d)[1 mark]State one reason why the hydration of ethene is more efficient than fermentation for making ethanol.
Question 227
3 marks · Normal
Answer and see the solution →Ethanol is used as a fuel in some countries and can be produced either by fermentation or by hydration of ethene.
Explain, using your knowledge of resources and processing, why some countries may switch from hydration of ethene to fermentation to produce ethanol in the future.
Question 228
4 marks · Normal
Answer and see the solution →The table below gives information about two methods of making ethanol.
Comparison of Ethanol Production Methods Feature Fermentation Hydration of Ethene Raw material Corn or sugar cane (renewable) Ethene from crude oil (non-renewable) Process type Batch, slow Continuous, fast Energy requirement Low High Product purity Impure, needs further processing Very pure (a)[2 marks]Based on the table, give two reasons why a country with limited access to crude oil and plenty of farmland might prefer fermentation to make ethanol.
(b)[1 mark]Give one disadvantage to this country of using fermentation rather than hydration of ethene.
(c)[1 mark]Suggest one way the country could improve the efficiency of ethanol production using fermentation.
Question 229
3 marks · Normal
Answer and see the solution →A factory can produce ethanol by either fermentation or hydration of ethene. Each method has a different efficiency and energy requirement, as shown in the table below.
Method Percentage Yield (%) Energy Input per Tonne Ethanol (kJ) Fermentation 60 2,500 Hydration of ethene 95 6,000 (a)Calculate the amount of ethanol (in tonnes) produced from 1000 tonnes of raw material by each method.
(i)[1 mark]Fermentation
(ii)[1 mark]Hydration of ethene
(b)[1 mark]Which method requires less energy per tonne of ethanol produced? Show how you use the data to decide.
Question 230
6 marks · Normal
Answer and see the solution →Ethanol is an important organic compound with many uses, including as a fuel and a chemical feedstock.
(a)[1 mark]Describe one observable colour change when ethanol is oxidised by heating with potassium dichromate(VI) in dilute sulfuric acid.
(b)[1 mark]Write a word equation for the oxidation reaction described in part (a).
(c)[2 marks]State the role of sulfuric acid in this oxidation reaction.
(d)[2 marks]Describe how ethanol can be produced by fermentation.