Cracking

Cracking changes large molecules into smaller, more useful ones by breaking them apart.

Cracking breaks these larger alkane molecules into smaller hydrocarbon molecules. The products are described as more useful because smaller hydrocarbons can be used for purposes such as fuels or as starting materials for making other chemicals. The reasons for differences in demand are considered separately; the essential idea here is that cracking converts molecules rather than merely sorting them.

Cracking changes some of those large molecules into products with more useful applications; it does not simply separate them from a mixture.

Cracking turns some of those larger molecules into smaller, more useful ones. Unlike fractional distillation, which separates molecules, cracking is a chemical reaction that changes them.