The table shows the supply and the demand for some fractions from crude oil at a refinery.
| Fraction | Supply from crude oil (%) | Demand from customers (%) |
|---|---|---|
| refinery gases | 3 | 4 |
| petrol | 12 | 27 |
| paraffin | 13 | 8 |
| diesel | 20 | 23 |
| fuel oil and bitumen | 52 | 38 |
The refinery cracks some of the fuel oil.
Use the table to explain why.
Describe the conditions used to crack hydrocarbons.
Cracking makes shorter alkanes and alkenes.
Complete the equation for cracking C14H30\mathrm{C_{14}H_{30}}C14H30.
C14H30→C8H18+2\mathrm{C_{14}H_{30} \rightarrow C_{8}H_{18} + 2}C14H30→C8H18+2 ......
Dodecane, C12H26\mathrm{C_{12}H_{26}}C12H26, is cracked to make hexane, C6H14\mathrm{C_{6}H_{14}}C6H14, and ethene as the only other product.
Write the balanced symbol equation for this reaction.
Explain why the alkenes made by cracking are useful to the petrochemical industry.
Modern life is crucially dependent on hydrocarbons.
Give two different uses of hydrocarbons from crude oil, other than as fuels for vehicles.
63 exam-style questions on OCR GCSE Chemistry 6.2 Organic chemistry, covering 6.2.1 Crude oil and fractional distillation, 6.2.2 Cracking and dependence on hydrocarbons, 6.2.3 Functional groups and homologous series, 6.2.4 Reactions of alkanes, alkenes and alcohols, 6.2.5 Addition polymerisation and repeat units, 6.2.6 Naturally occurring polymers, 6.2.7 Chemical cells and fuel cells, and 6.2.8 Condensation polymerisation and how to make one. Each one has a worked solution and a mark scheme showing where the marks go.