Cambridge IGCSE Chemistry · Syllabus 0620 · Organic Chemistry
Fractional Distillation
What is Fractional Distillation?
The separation of a mixture of liquids into fractions with different boiling point ranges, carried out in a column that is hot at the bottom and cool at the top, so that each fraction condenses at the height where the temperature matches its boiling range.
This definition is part of the Organic Chemistry chapter in Cambridge IGCSE Chemistry.
Common mistakes with Fractional Distillation
- “Petroleum is a compound that is broken down in the fractionating column.” Core 11.3.4Core 11.3.5 why it fails Two errors at once: petroleum is not a compound, and distillation does not break anything down. correct Petroleum is a mixture of hydrocarbons. Fractional distillation separates that mixture using differences in boiling point. No bonds inside the molecules are broken. Taught in 11.3.
- 5. “Fractional distillation breaks petroleum down into its fractions.” Core 11.3.5 defect The verb “breaks down”, which describes a chemical change. why Petroleum is a mixture, and distillation is physical. Every molecule survives intact; nothing is broken. repair Write separates. Reserve “breaks down” for cracking. transfer State one difference in the products of distillation and of cracking that proves one is chemical and the other is not.