Video: Identifying a Substance for Which Crude Oil Is Not an Important Source from a Set

Which of the following is crude oil not an important source for? [A] Gasoline [B] Butane [C] Kerosene [D] Hexane [E] Glucose


Video Transcript

Which of the following is crude oil not an important source for? A) Gasoline, B) butane, C) kerosene, D) hexane, E) glucose.

To answer this question, we need to consider how crude oil is formed, what it contains, and how useful products are obtained from it. Crude oil is a mixture of hydrocarbon compounds. It was formed over millions of years from the remains of dead-sea creatures, such as algae and plankton. The sea creatures lived in the oceans millions of years ago. When they died, their remains were compressed under layers of sediment under anaerobic conditions, that is, without oxygen. After millions of years under anaerobic conditions, the remains of the sea creatures were transformed into crude oil. So crude oil is a mixture of hydrocarbon compounds. A hydrocarbon is a compound containing the elements hydrogen and carbon only.

The hydrocarbon mixture that we call crude oil can be a viscous thick liquid or runny liquid, depending upon where it originates from. Because it’s a mixture of hydrocarbons, useful products must be separated from the crude-oil source. This is done using a process called fractional distillation. During fractional distillation, the hydrocarbons in the crude-oil mixture are separated by first being vaporized and then condensed at different levels in a fractionating tower. The fractions as the separated components of crude oil are known, which are still mixtures, are condensed at different levels so that the products can be collected.

Gasoline is collected near the top of the fractionating tower is a fuel used for cars. Kerosene has a higher boiling point. It is collected slightly lower down the fractionating tower. And it’s a fuel used for jet aircraft. Gasoline and kerosene are mixtures of hydrocarbons. And they are sourced directly from crude oil. Answers A and C are therefore not correct answers.

The gas fractions and liquid fractions can be further refined to produce pure hydrocarbons. Often, alkanes are obtained. In this way, butane and hexane can be obtained following further separation of each fraction. Butane and hexane do depend upon crude oil as their source. So answers B and D are also incorrect. Our final response remaining is answer E, which is glucose. Glucose, with the molecular formula C₆H₁₂O₆, is a carbohydrate. In addition to carbon and hydrogen, oxygen has been introduced into this molecule. Since crude oil is formed under anaerobic conditions, oxygen is not found in its hydrocarbon constituents. Glucose can be formed when plants photosynthesize, which is a reaction involving carbon dioxide and water. Glucose is not formed from crude oil. Therefore, crude oil is not an important source for its production.

Glucose is the correct answer here.

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