"in the process of fractional distillation, the components of petroleum are separated according to "

Boiling points. The different components of petroleum have different boiling points. When a component's boiling point is reached it escapes, as gaseous phase, is collected and cooled back. The components with the lowest boiling point will be collected first in fractional distillation while those with highest boiling points, last.
Petroleum is composed of oil, tar, petrol, kerosene, paraffin, and etcetera.

Silicon is cut into tiny pieces for computer chipslead is melted to form pelletsliquid water freezes to form ice