Chemical reactions of the alkenes
3 marks · EasyDescribe what happens to the double bond in an alkene during an addition reaction.
Name one substance that can react with an alkene in an addition reaction.
State one product formed when ethene reacts with steam in an addition reaction.
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(a) The double bond is broken and new atoms are added to the carbons · must show double bond breaks/single bond forms, atoms added
(b) hydrogen, bromine, or steam (H2, Br2, H2O/steam) · must show any suitable reactant (e.g., hydrogen, halogen, steam)
(c) ethanol · must show ethanol
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Marking points
B1 (a) · 1 mark · Describes that the double bond breaks and new atoms are added.
B1 (b) · 1 mark · Names a correct reactant: hydrogen, halogen, or steam.
B1 (c) · 1 mark · States a correct product: ethanol.
Worked solution
a) The double bond in an alkene breaks, forming a single bond, and allows other atoms to be added to the molecule.
b) Example: hydrogen, bromine or steam.
c) When ethene reacts with steam, ethanol is formed.