CAIE A Level Chemistry 9701 · An introduction to organic chemistry
Explain why the carbon atoms in ethene () have a planar arrangement, whereas the carbon atoms in ethane () have a non-planar arrangement. In your answer, refer to the hybridisation of the carbon atoms and the bond angles in each molecule.
4 marks, so the mark scheme is looking for about 4 separate creditworthy points. Making the same point twice in different words earns it once.
Explain means: Give the reasons or the mechanism: why or how something happens. Link each point to the next with because, so or which means. A list of facts with no links usually loses the reasoning marks.
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