Complex sentence: It consists mostly of organic compounds obtained by the fractional distillation of petroleum, enhanced with a variety of additives; a 42-gallon barrel of crude oil yields about 19 gallons of gasoline, when processed in an oil refinery.
Split into simpler sentences: It consists mostly of organic compounds obtained by the fractional distillation of petroleum, enhanced with a variety of additives. A 42-gallon barrel of crude oil yields about 19 gallons of gasoline, when processed in an oil refinery.