Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Chapter
Alkenes
106 practice questions
Topics covered
Practice questions
51–60 of 106
Question 51
4 marks · Normal
Answer and see the solution →A student compares the combustion reactions of three alkenes. The table shows the number of carbon and hydrogen atoms in each.
Alkene Number of carbon atoms (n) Number of hydrogen atoms Ethene 2 4 Propene 3 6 Pentene 5 10 (a)[1 mark]State the general formula for alkenes.
(b)[2 marks]Explain the pattern between the number of carbon atoms and hydrogen atoms in these alkenes.
(c)[1 mark]Write the molecular formula for hexene.
Question 52
1 mark · Normal
Answer and check →Which statement best describes an addition reaction of ethene?
- A.Two ethene molecules join together to form a longer chain.
- B.Ethene reacts with oxygen to form carbon dioxide and water.
- C.Bromine atoms add across the double bond of ethene.
- D.Hydrogen atoms are lost from ethene forming ethyne.
Question 53
4 marks · Normal
Answer and see the solution →This question is about reactions of propene (C3H6).
(a)[1 mark]Explain why propene is classified as an unsaturated hydrocarbon.
(b)[1 mark]Write a word equation for the addition reaction of propene with hydrogen.
(c)[2 marks]Describe what is formed when propene burns in a plentiful supply of air.
Question 54
2 marks · Normal
Answer and see the solution →Alkenes are a family of unsaturated hydrocarbons that undergo two main types of chemical reactions: combustion and addition.
Describe what happens during:
(a)[1 mark](i) the combustion of an alkene in oxygen
(b)[1 mark](ii) an addition reaction of an alkene
Question 55
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 56
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 57
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 58
1 mark · Easy
Answer and see the solution →State the colour change observed when bromine water reacts with ethene.
Question 59
3 marks · Easy
Answer and see the solution →A student tests samples of pentane and pent-1-ene with bromine water.
(a)[1 mark]State what is observed when bromine water is added to pent-1-ene.
(b)[1 mark]State what is observed when bromine water is added to pentane.
(c)[1 mark]Explain why these observations allow you to distinguish between pentane and pent-1-ene.
Question 60
2 marks · Easy
Answer and see the solution →Write the balanced chemical equation for the addition reaction between propene ( ) and bromine ( ). State the name of the organic product formed.