Question 1

Gasohol contains

Accepted Answer

Gasohol is a fuel mixture of gasoline and ethanol, typically containing up to 10% ethanol.

Question 2

Which of the following is not true about benzene?

Accepted Answer

The formula for benzene is C6H6, not C₆H₁₂.

Question 3

Which is a characteristic of alkanes?

Accepted Answer

Alkanes are saturated hydrocarbons that contain only single bonds between carbon atoms.

Question 4

Which of the following compounds would you expect to have the highest octane rating?

Accepted Answer

Isooctane (also known as 2,2,4-trimethylpentane) has the highest octane rating because it has a branched structure that resists premature ignition, allowing for a smoother combustion and thus a higher octane rating. Pentane and heptane are linear hydrocarbons with lower octane ratings, while hexane is still a linear hydrocarbon but with a slightly higher octane rating than the other two linear hydrocarbons.

Question 5

Fractional distillation of petroleum

Accepted Answer

Fractional distillation separates crude oil into different fractions, each of which contain a range of hydrocarbons with similar boiling points. These fractions can then be further refined and processed to produce different petroleum products such as gasoline, diesel fuel, and lubricating oils. Fractional distillation does not purify all hydrocarbons and is not the final step in refining gasoline. It also does not break down large molecules into smaller ones.

Question 6

Which fossil fuel has a molecular structure containing cyclic hydrocarbons?

Accepted Answer

Coal is composed of complex organic compounds including cyclic hydrocarbons such as aromatic (benzene) and heterocyclic compounds (pyridine, thiophene). Liquid propane and natural gas are primarily composed of alkanes (linear hydrocarbons) and do not contain cyclic hydrocarbons.

Question 7

The fuel identified as M85 is

Accepted Answer

M85 is a fuel mixture consisting of 85% methanol and 15% gasoline, commonly used as an alternative fuel for vehicles.

Question 8

Which alcohol is called wood alcohol?

Accepted Answer

Methanol is called wood alcohol because it can be derived from wood through destructive distillation. It is toxic when ingested and can cause blindness or death.

Question 9

Which fossil fuel burns cleaner and more completely?

Accepted Answer

Natural gas is the cleanest burning fossil fuel as it produces less pollution and greenhouse gas emissions compared to coal, petroleum, and even wood. It also burns more completely, releasing less waste products into the environment.

Question 10

Carcinogens are compounds that are

Accepted Answer

Carcinogens are compounds that can cause cancer.

Question 11

A coal gasification process involving a catalyst, carbon monoxide, hydrogen, steam and coal produces

Accepted Answer

The coal gasification process involving a catalyst, carbon monoxide, hydrogen, steam and coal produces methane and carbon dioxide. This is because the process converts coal into a gas mixture containing carbon monoxide, hydrogen and other gases. The carbon monoxide and hydrogen then react further to produce methane and carbon dioxide.

Question 12

The octane rating of straight run gasoline from fractional distillation of petroleum can be raised by

Accepted Answer

The octane rating of gasoline can be increased by catalytic reforming, which rearranges or reforms hydrocarbons in the gasoline to improve its quality, and by adding oxygenates such as tertiary-butyl alcohol or ethanol, which help in combustion and thus increase the octane rating.

Question 13

The combustible products of most coal gasification techniques are

Accepted Answer

Most coal gasification techniques produce a gas mixture of hydrogen and carbon monoxide, known as syngas.

Question 14

Which of the following is not true about the compound MTBE?

Accepted Answer

MTBE is not made by fermentation, but is instead made by a chemical reaction between methanol and isobutylene. Choices A, C, and D are true - MTBE is an ether, it is considered a possible carcinogen, and it is used as an additive to oxygenate gasoline.

Question 15

Which substance is grain alcohol?

Accepted Answer

Grain alcohol refers to ethanol, which is a type of alcohol that is made from grains such as corn, wheat, or barley. Methanol, MTBE, and benzene are not types of grain alcohol. Methanol is a poisonous type of alcohol that is not safe for consumption, while MTBE and benzene are both chemicals that are used in gasoline.

Question 16

What are the bond angles around the carbon atoms in alkanes?

Accepted Answer

The bond angles around the carbon atoms in alkanes are approximately 109.5 degrees, which is characteristic of sp3 hybridized orbitals forming a tetrahedral geometry.

Question 17

Gasoline is a

Accepted Answer

Gasoline is a mixture of various hydrocarbons, ranging from C₅ to C₁₂ carbon atoms. Choice D correctly represents this range of hydrocarbons. Choices A and B are incorrect because gasoline is not a single hydrocarbon. Choice C is also incorrect because the range of hydrocarbons in gasoline includes more than just C₁₂ and C₁₆.

Question 18

Petroleum is separated into fractions in the refining process.Which of the following fractions has molecules with the largest size?

Accepted Answer

Paraffin wax has the largest molecules, consisting of long chains of carbon and hydrogen atoms.

Question 19

The purpose of coal gasification is to

Accepted Answer

The purpose of coal gasification is to produce a relatively clean burning, gaseous fuel. This is achieved by converting solid coal into a gas that can be burned for energy, with reduced emissions compared to traditional coal burning.

Question 20

Octane ratings are based on comparison of the fuel being tested with the knocking properties of mixtures of

Accepted Answer

Octane ratings are based on the comparison of the fuel being tested with the knocking properties of mixtures of isooctane (high octane rating) and heptane (low octane rating). Therefore, choice C) isooctane and heptane is the best option.

Quiz 12: Energy and Hydrocarbons