Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Section
The test for unsaturated compounds
19 practice questions
Practice questions
1–8 of 8 · Normal
Question 1
2 marks · Normal
Answer and see the solution →State the overall type of reaction that occurs when bromine water reacts with ethene, and give the name of the organic product formed.
Question 2
4 marks · Normal
Answer and see the solution →(a)[1 mark]Describe the result you would see when bromine water is shaken with a liquid alkene.
(b)[1 mark]Describe what you would see if bromine water is shaken with a liquid alkane, under the same conditions.
(c)[2 marks]Explain how you can use this test to distinguish between an alkene and an alkane.
Question 3
3 marks · Normal
Answer and see the solution →A student wants to test whether an unknown colourless liquid is an alkane or an alkene. The student adds a few drops of bromine water to the liquid in a test tube and shakes it. After a short time, the orange colour disappears and the mixture becomes colourless. Explain what conclusion the student should make about the liquid and the reason for this result.
Question 4
4 marks · Normal
Answer and see the solution →A student investigates the reaction between different alkenes and bromine water. The table shows the results.
Observations on addition of bromine water to different compounds. Compound Observation after adding bromine water Ethene Colourless Propene Colourless Butane Orange Cyclohexene Colourless (a)[2 marks]Which of these compounds are alkenes? Give a reason for your choice.
(b)[2 marks]Write a balanced equation for the reaction of ethene with bromine water.
Question 5
1 mark · Normal
Answer and check →Which observation confirms that a compound is an alkane, rather than an alkene, when tested with bromine water?
- A.The solution becomes colourless.
- B.The solution stays orange.
- C.A gas is given off.
- D.The solution turns milky.
Question 6
2 marks · Normal
Answer and see the solution →State the displayed formula of the product formed when but-1-ene reacts with bromine water, and give its name.
Question 7
4 marks · Normal
Answer and see the solution →(a)[1 mark]State what is meant by an unsaturated compound.
(b)[2 marks]Describe a chemical test to distinguish between hexane and hex-1-ene.
(c)[1 mark]Predict and state the result for each compound.
Question 8
3 marks · Normal
Answer and see the solution →When 28 g of ethene () gas reacts completely with bromine () solution in an addition reaction, calculate the maximum mass of 1,2-dibromoethane () that can be formed.
Give your answer to the nearest whole number. (Relative atomic masses: H = 1, C = 12, Br = 80)