Crude oil: Practice Questions

Crude oil is separated into useful fractions by fractional distillation. Which property of the fractions decreases as the boiling point decreases (i.e., moving from bitumen at the bottom to refinery gases at the top)?

Fractional distillation is the industrial process used to separate crude oil into useful fractions. Which physical property of the components is primarily utilized to achieve this separation?

Why does the viscosity of the hydrocarbon fractions obtained from crude oil increase as the boiling point increases?

Catalytic cracking is an essential industrial process applied to crude oil fractions. What is the primary reason why cracking is necessary?

Catalytic cracking is performed on long-chain alkanes to meet the high demand for lighter fractions. When a long-chain alkane molecule undergoes cracking, what is the typical result in terms of the chemical nature of the products?

Explain why the industrial process of catalytic cracking is necessary, referring to the balance between supply and demand for different fractions.

Crude oil is a vital resource separated by fractional distillation.
a) Explain the principle of fractional distillation as applied to crude oil, mentioning the key property that allows separation.
b) Describe the general trend in the boiling points and viscosity of fractions collected from the top to the bottom of the fractionating column.
c) Give one common use for the fraction collected at the top of the column and one for the fraction collected near the bottom.

Crude oil is a complex mixture of hydrocarbons that must be processed to produce useful fuels and chemicals.
(a) Describe how the temperature gradient within a fractional distillation column enables the separation of crude oil, and identify which fraction would be collected at the bottom of the column.
(b) Compare the physical properties of gasoline and bitumen with respect to their boiling point, viscosity, and color.
(c) Explain why the combustion of gasoline in a car engine results in the formation of oxides of nitrogen, even though gasoline does not contain nitrogen.
(d) A sample of dodecane, \(C_{12}H_{26}\), is processed through catalytic cracking to produce one molecule of octane, \(C_8H_{18}\), and two molecules of an identical alkene. State the required industrial conditions (catalyst and temperature) and provide a balanced chemical equation for this reaction.