Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Unit
Organic Chemistry
785 practice questions
Topics covered
Practice questions
471–480 of 785
Question 471
2 marks · Normal
Answer and see the solution →Describe what happens to ethanol when it is heated with potassium dichromate(VI) in dilute sulfuric acid. Include what is formed in the reaction.
Question 472
4 marks · Normal
Answer and see the solution →(a)[1 mark]State the initial colour of potassium dichromate(VI) solution before ethanol is added and heated.
(b)[2 marks]Describe the colour change observed when ethanol is oxidised by heating with potassium dichromate(VI) in dilute sulfuric acid.
(c)[1 mark]Name the ion that causes the final colour observed.
Question 473
3 marks · Normal
Answer and see the solution →A student plans to oxidise ethanol using potassium dichromate(VI) in dilute sulfuric acid. Explain, with reasoning, the role of the sulfuric acid in this reaction and what would happen if it was not included.
Question 474
2 marks · Hard
Answer and see the solution →Describe what happens when ethanol is heated with potassium dichromate(VI) in dilute sulfuric acid. In your answer, name the organic product and state the type of chemical change occurring.
Question 475
5 marks · Hard
Answer and see the solution →(a)[1 mark]A student adds ethanol to a solution of potassium dichromate(VI) in dilute sulfuric acid. She then heats the mixture in a water bath.
State the initial colour of the potassium dichromate(VI) solution before the ethanol is added and heated.
(b)[2 marks]Describe the colour change observed as the reaction occurs and explain what causes this change.
(c)[1 mark]Which ion is responsible for the green colour observed at the end of the reaction?
(d)[1 mark]Explain why the colour change provides evidence that a redox reaction has taken place.
Question 476
2 marks · Hard
Answer and see the solution →Explain why dilute sulfuric acid must be present when potassium dichromate(VI) is used to oxidise ethanol. Include in your answer the role that the acid plays in the reaction.
Question 477
1 mark · Easy
Answer and see the solution →State the starting material used in the fermentation process to make ethanol.
Question 478
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 479
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 480
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.