I have to write the reactions of:
1) ethene so that results ethene oxide, ethylbenzene
2) propene so that results isopropylbenzene
3) butane --> butadiene

First you should try these reactions. You know the reactions that have been presented in your class so far. I am assuming that you ae looking for lab syntheses as opposed to their industrial preparations. How do you think you could do these syntheses. Hints: epoxides are made either with alkenes and peroxyacids or via halohydrins. Alkyl benzenes are prepared with one of the variations of the Freidel - Crafts reactions. Butadiene could be prepared with a double dehydrohalogenation.
How are you doing? Give the reactions a try and we will help you over the difficult parts.