Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Chapter
Alkenes
106 practice questions
Topics covered
Practice questions
1–10 of 18 · Hard
Question 1
2 marks · Hard
Answer and see the solution →Explain why alkenes are classified as unsaturated hydrocarbons and describe the significance of the C=C bond in their chemical reactivity.
Question 2
5 marks · Hard
Answer and see the solution →Butene ( C4H8 ) has several isomers.
(a)[2 marks]Draw the displayed formula of the branched-chain isomer of butene.
(b)[1 mark]Draw the displayed formula of one straight-chain isomer of butene where the double bond is at the end of the carbon chain.
(c)[2 marks]Explain why these structures are isomers of each other.
Question 3
2 marks · Hard
Answer and see the solution →State the name and draw the displayed formula of the alkene that has four carbon atoms in a continuous chain with the double bond between the second and third carbon atoms.
Question 4
2 marks · Hard
Answer and see the solution →A student claims that all alkenes have the same general formula. State this general formula and explain how it shows that alkenes are unsaturated.
Question 5
5 marks · Hard
Answer and see the solution →The physical properties of alkenes with 2 to 4 carbon atoms show a trend.
(a)[2 marks]State the physical state of ethene, propene and butene at room temperature.
(b)[2 marks]Describe how the boiling points of these alkenes change as the number of carbon atoms increases from ethene to butene.
(c)[1 mark]Explain why the trend you described in part (b) occurs.
Question 6
2 marks · Hard
Answer and see the solution →State the general formula for alkenes. Explain, using your formula, how you can determine the number of hydrogen atoms in an alkene containing 9 carbon atoms.
Question 7
2 marks · Hard
Answer and see the solution →State the products formed when pentene (C5H10) undergoes complete combustion in oxygen. Write a balanced chemical equation for the reaction.
Question 8
5 marks · Hard
Answer and see the solution →This question is about reactions of hexene (C6H12).
(a)[2 marks]Describe what happens to the C=C double bond in an addition reaction of hexene.
(b)[2 marks]State the product formed when hexene reacts with hydrogen in an addition reaction. Suggest the molecular formula of the product.
(c)[1 mark]Write a chemical equation for the complete combustion of hexene.
Question 9
2 marks · Hard
Answer and see the solution →Give a general description of what happens to an alkene during a combustion reaction. Explain why alkenes are not normally used as fuels.
Question 10
2 marks · Hard
Answer and see the solution →State and explain what you would observe when bromine water is added to but-2-ene. Write a chemical equation for the reaction.