Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Unit
Organic Chemistry
785 practice questions
Topics covered
Practice questions
191–200 of 317 · Easy
Question 191
3 marks · Easy
Answer and see the solution →(a)[1 mark]Describe the observable change in colour that occurs when ethanol is oxidised by heating with potassium dichromate(VI) in dilute sulfuric acid.
(b)[1 mark]What does this colour change indicate about the potassium dichromate(VI) during the reaction?
(c)[1 mark]Suggest what you would observe if the solution is heated without adding ethanol.
Question 192
2 marks · Easy
Answer and see the solution →Ethanol can be oxidised by heating it with potassium dichromate(VI) in dilute sulfuric acid.
Calculate the number of different substances (including ethanol and all reagents used) that must be present in the test-tube for this reaction to occur, according to standard laboratory practice.
Show your working.
Question 193
2 marks · Easy
Answer and see the solution →The oxidation of ethanol with potassium dichromate(VI) requires dilute sulfuric acid.
A chemist accidentally forgets to add any dilute sulfuric acid to the test-tube, while potassium dichromate(VI) and ethanol are both present.
Calculate the number of moles of H+ ions available to the reaction in this mistake, assuming none are present in the other reagents.
Show your working and state the reason for your answer.
Question 194
1 mark · Easy
Answer and see the solution →State the starting material used in the fermentation process to make ethanol.
Question 195
3 marks · Easy
Answer and see the solution →The diagram below shows a simple set-up for producing ethanol by fermentation.
Apparatus for fermentation (a)[1 mark]Name the microorganism used in this process.
(b)[1 mark]State one condition, other than the absence of air, needed for fermentation to occur efficiently.
(c)[1 mark]What is observed in the boiling tube containing limewater when fermentation takes place?
Question 196
2 marks · Easy
Answer and see the solution →In a fermentation reaction, 60 g of glucose are converted to ethanol and carbon dioxide. Calculate the maximum mass of ethanol that could be produced, using the equation:
(Relative formula masses: C6H12O6 = 180, C2H5OH = 46)
Question 197
2 marks · Easy
Answer and see the solution →Ethanol may be made by fermentation or by reacting ethene with steam.
Explain why it is important to keep air out of the fermentation vessel.
Question 198
3 marks · Easy
Answer and see the solution →A student carries out fermentation at different temperatures. The table shows the volume of ethanol made after 3 days.
Ethanol production vs temperature Temperature (°C) Ethanol produced (cm³) 15 12 25 30 35 33 45 10 (a)[1 mark]At which temperature was the highest volume of ethanol produced?
(b)[1 mark]Suggest why the volume of ethanol is lower at 45°C.
(c)[1 mark]How does temperature affect the rate of fermentation based on this data?
Question 199
1 mark · Easy
Answer and see the solution →Name the chemical that is added to ethene for the direct industrial manufacture of ethanol.
Question 200
3 marks · Easy
Answer and see the solution →Ethanol can be made by adding steam to ethene.
(a)[1 mark]Write the word equation for this reaction.
(b)[1 mark]State one condition needed for this reaction to occur.
(c)[1 mark]Name the type of compound to which ethene belongs.