原油：练习题

Which of the following statements about crude oil is correct?

In the industrial process of fractional distillation, crude oil is separated into fractions. Which statement best explains how this separation occurs?

In a fractionating column used for the industrial distillation of crude oil, various fractions are collected based on their boiling points. Which statement correctly identifies the characteristics of the hydrocarbons collected at the top of the fractionating column compared to those collected at the bottom?

Which process is used to separate the different hydrocarbons in crude oil into fractions with similar numbers of carbon atoms?

Define the term hydrocarbon and state the general formula for the homologous series of alkanes found in crude oil.

State what is meant by the term finite resource in relation to crude oil and identify the ancient remains from which this mixture was formed over millions of years.

Crude oil is a finite resource found in the Earth's crust. It consists of a very large number of compounds.
(a) State what crude oil is a mixture of and define the type of compounds mostly found within it. (2 points)
(b) Briefly explain why the compounds in crude oil can be separated into fractions by fractional distillation. (1 point)

Crude oil is a complex mixture of hydrocarbons that must be processed to be useful.
(a) In a fractionating column, as shown in the diagram, the temperature is higher at the bottom than at the top. Explain how this temperature gradient allows crude oil to be separated into fractions. (3 points)
(b) Some of the heavier fractions are broken down into smaller, more useful molecules. Name this industrial process and state one essential condition required for it to take place. (2 points)