Chemistry- C7 Part A

1. ... is thermal decomposition, breaking molecules down with heat. 1) Heat long chains to vapourise them. 2) Vapour passed over hot aluminium oxide catalyst. 3) Long chain molecules split apart on the catalyst- catalytic ... Also steam ... (8)
4. ... are saturated compounds, each carbon atom forms 4 covalent bonds. First four in the series are: Methane, Ethane, Propane and Butane (7)
7. ... series is a group of organic compounds that react similarly (10)
8. ... is a fossil fuel, a mix of hydrocarbons. Its mainly made from plankton, and drilled up after millions of years. It is non-renewable so used up much faster than produced, and a finite resource meaning it will run out one day (5, 3)

2. ... splits long hydrocarbon chains as they don't have much use. long chains are turned into smaller, more useful chains. Alkenes are also produced, starting material in polymers. Some products are used as fuel (8)
3. As a ... chain changes, the properties change. A shorter chain- More runny, less viscous. More volatile, lower boiling points. More flammable. These properties effect how they are used (11, 5)
5. A ... is any compound made from hydrogen and carbon atoms only (11)
6. ... are the simplest type of hydrocarbon- General Formula: CnH2n+2. They are a homologous series (7)
9. Complete ... of hydrocarbons releases lots of energy. During ... hydrogen and carbon are oxidised. Hydrocarbons are used as fuel because of the amount of energy released (10)
10. Different compounds in crude oil are separated by Fractional ... 1) Oil is heated, turned into gas, into the fractionating column. 2) Temperature gradient in column, cooler as you go up. 3) Hydrocarbons have varying boiling points so times change (12)

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