Chemical reactions of the alkenes
3 marks · EasyState what is meant by an addition reaction of an alkene.
Write the word equation for the reaction between ethene and bromine.
What structural feature of ethene allows it to take part in addition reactions?
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
(a) A reaction in which atoms are added across the double bond of an alkene · must show atoms/halogens/hydrogen added across double bond
(b) ethene + bromine → dibromoethane · must show reactants: ethene, bromine, product: dibromoethane
(c) The C=C double bond · must show C=C double bond
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · Defines addition reaction as adding atoms across double bond or breaking double bond and adding atoms.
B1 (b) · 1 mark · Correct word equation: ethene + bromine → dibromoethane.
B1 (c) · 1 mark · Identifies double bond as key structural feature.
Worked solution
a) An addition reaction of an alkene is a reaction where atoms are added to the carbon atoms of the double bond, causing it to become a single bond.
b) ethene + bromine → dibromoethane
c) Ethene contains a C=C double bond, which allows it to undergo addition reactions.