Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Section
Chemical reactions of the alkenes
19 practice questions
Practice questions
1–8 of 8 · Normal
Question 1
2 marks · Normal
Answer and see the solution →State the type of chemical reaction that occurs when ethene reacts completely with oxygen. Write the names of the two products formed in this reaction.
Question 2
4 marks · Normal
Answer and see the solution →Butene (C4H8) is an alkene that can undergo combustion and addition reactions.
(a)[2 marks]Write the balanced chemical equation for the complete combustion of butene (C4H8) in oxygen.
(b)[2 marks]Describe what happens to the C=C double bond when butene reacts with bromine, Br2.
Question 3
3 marks · Normal
Answer and see the solution →An alkene has 8 carbon atoms in its molecule.
Calculate the number of hydrogen atoms present in one molecule of this alkene. Show your working.
Question 4
3 marks · Normal
Answer and see the solution →Alkenes are described as unsaturated hydrocarbons.
Explain what 'unsaturated' means and how you can test for unsaturation using a chemical reaction.
Question 5
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 6
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 7
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 8
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