This question was beautiful.
This is what I did:
1. Fractional distillation of petroleum
2. Cracking of a hydrocarbon to form ethene (equation)
3. Photosynthesis to produce glucose (equation)
4. Fermentation of glucose for ethanol (equation)
5. Dehydration of ethanol to form ethene (equation)
6. Polymerisation to form high density polyethene using Zeiger catalyst
7. Equation for polymerisation of ethene and diagram of HDPE with explanation of properties to explain why it is useful as a bottle
I loved this question. Absolutely loved it. And all of this fit into the space provided.