List two ways in which our society uses petroleum. What happens to the petroleum that is used for energy. Crude oil is made mostly of hydrocarbons . The refining process separates crude oil by distillation into fractions. The refining process separates crude oil by distillation into fractions.
High viscosity flows slowly and with difficulty, like honey.
Low viscosity flows readily, like water. B. 5 Petroleum molecules Petroleum is made mostly of carbon and hydrogen atoms. Hydrocarbons are molecular compounds. Hydrogen atoms are attached to this chain. These hydrogen atoms are bonded to the carbon by chemical bonds.