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Crude oil is a finite resource. Petrol and other fuels are produced from it by fractional distillation. These fuels are non-renewable resources. Cracking helps match supply of fractions with demand.

The alkanes, alkenes, alcohols and carboxylic acids are four different homologous series of organic compounds. Their different chemical properties are due to their characteristic functional groups.

Addition polymers are made from molecules containing C=C bonds. Polymers have different uses that depend on their properties. DNA, starch and proteins are biological polymers.

A chemical cell produces a voltage until one of the reactants is used up. In a hydrogen-oxygen fuel cell, hydrogen and oxygen are used to produce a voltage, and water is the only product.

Understanding how to approach exam questions helps to boost exam performance. Question types will include multiple choice, structured, mathematical and practical questions.