Petroleum products are separated based on differences in their boiling points. This is achieved through fractional distillation, a process where crude oil is heated and vaporized, then passed into a fractionating column. As the vapors rise and cool, different hydrocarbons condense at specific heights based on their boiling points, allowing collection of distinct fractions like gasoline, diesel, and kerosene.

Key equation for boiling point separation: $T=\frac{\mathrm{\Delta H}}{\mathrm{\Delta S}}$, where T is boiling point, ΔH is enthalpy of vaporization, and ΔS is entropy change.

Final answer: fractional distillation