A research chemist has two different hydrocarbons, E and F. Both have the molecular formula C4H8\mathrm{C_{4}H_{8}}C4H8.
E has the structure CH2=CHCH2CH3\mathrm{CH_{2}=CHCH_{2}CH_{3}}CH2=CHCH2CH3 and F has the structure CH3CH=CHCH3\mathrm{CH_{3}CH=CHCH_{3}}CH3CH=CHCH3. Both E and F decolourise bromine water.
Show that the formula C4H8\mathrm{C_{4}H_{8}}C4H8 fits the general formula of the alkenes.
Name E and F.
Calculate the percentage by mass of carbon in C4H8\mathrm{C_{4}H_{8}}C4H8 and explain why every alkene has this same percentage by mass of carbon. Relative atomic masses: H = 1, C = 12
E and F both react with bromine. Explain why the two products have the same molecular formula but different structures.
The chemist burns 1 mole of E and 1 mole of F separately in excess oxygen. Explain why both produce the same amounts of carbon dioxide and water.
36 exam-style questions on Edexcel GCSE Chemistry 10.2 Hydrocarbons, covering 10.2.1 Formulae and structures of the alkanes, 10.2.2 Alkenes and the C=C functional group, 10.2.3 Addition reactions of alkenes and testing for unsaturation, and 10.2.4 Combustion of alkanes and alkenes. Each one has a worked solution and a mark scheme showing where the marks go.