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Explain Fractional Distillation (6 Marks)

Fractional distillation is the process of separating the different hydrocarbon compounds within crude oil (Show understanding of fractional distillation through context) . First the crude oil is heated/vaporised at around 350C(1st Mark) and fed into a fractionating column which has a temperature gradient, meaning that Its hotter at the bottom and cooler at the top (2nd Mark). Long chain hydrocarbons with higher boiling points will condense at lower fractions in the column,whilst shorter chain hydrocarbons with lower boiling points will condense at higher fractions in the column (3/4 Mark). These fractions now hold liquid hydrocarbons which will be collected through pipes. Some hydrocarbons with very low boiling points such as natural gases will escape out of the top of the column whilst some hydrocarbons with very high boiling points do not vaporise such as bitumen, which leaves through the bottom of the column. (5th Mark)6th Mark may be awarded based off of SPAG (Spelling, Punctuation And Grammar), and structure of response.