Alkenes are a homologous series of unsaturated hydrocarbons.

1. (a)Name the alkene which has only three carbon atoms in its molecule.[1]
2. (b)Draw the structure of an unbranched and of a branched alkene. Show all of the atoms and all of the bonds in each structure. unbranched alkene branched alkene[2]
3. (c)Describe a chemical test that distinguishes an alkene from an alkane. chemical test result with alkene result with alkane[2]
4. (d)(i)Alkenes are manufactured by the cracking of long chain hydrocarbons. The equation for the cracking of C14H30 is shown. C14H30 → 2X + C8H18 Give two reasons why the cracking of long chain hydrocarbons is important.[2]
5. (d)(ii)Compound X contains 85.7% carbon by mass and 14.3% hydrogen by mass. Calculate, using the percentage composition data, the empirical formula of X. Show your working. State the molecular formula of X. empirical formula molecular formula[3]