CRUDE OIL [dchemlc]

Which of the following statements about crude oil are false?

• It is an infinite resource

• It is a non-renewable resource

• It is a mixture of hydrocarbons

• It is made up of carbon and hydrogen only

Answer explanation

Crude oil is a finite, non-renewable resource.

Crude oil is a mixture of hydrocarbons, compounds containing carbon and hydrogen only.

Which of the following statements about how the physical properties of hydrocarbons change with molecular size is false?

• Boiling point increases

• Liquids become more volatile

• Liquids become more viscous

• Liquids become darker in colour

Answer explanation

liquids become less volatile

What is the method used to separate crude oil into fractions?

• Fractional distillation

• Evaporation

• Chromatography

• Centrifuging

Answer explanation

Crude oil itself has no uses and it has to be separated into fractions before it can be used. These fractions are all mixtures, but each one contains a narrow range of sizes of hydrocarbons with similar boiling points. We use fractional distillation to separate crude oil into fractions. This is carried out in an oil refinery.

what is the temperature range used in catalytic cracking?

• 600-700

• 700-900

• 500-800

• 400-500

Answer explanation

The fuel oil fraction is heated to give a gas and then passed over a catalyst of silicon dioxide (also called silica) and aluminium oxide (also called alumina) at about 600-700 ' C. Cracking can also be carried out at higher temperatures without a catalyst (thermal cracking).

Which of the following is not a constituent of refinery gas?

• Ethane

• Propane

• Butane

• Pentane

Answer explanation

Refinery gases are a mixture of methane, ethane, propane and butane, which can be separated into individual gases if required. These gases are commonly used as liquefied petroleum gas (LPG) for domestic heating and cooking.

Which of the following is not used as a fuel in transportation?

• Diesel

• Kerosene

• Gasoline

• Refinery gas

Answer explanation

As with all the other fractions, petrol is a mixture of hydrocarbons with similar boiling points. It is used as a fuel in cars.

Kerosene is used as a fuel for jet aircraft.

This is used as a fuel for buses, lorries, some cars, and some railway engines.

What is bitumen used for?

• To make the top surface of roads.

• As a fuel for ships and for industrial heating

• For domestic heating and cooking

• For construction of vehicles

Answer explanation

Bitumen is a thick, black material, which is melted and mixed with small pieces of rock to make the top surface of roads.

What are the two catalysts used in catalytic cracking?

• Silicon dioxide

• Aluminium oxide

• Iron

• Platinum

• Vanadium oxide

Answer explanation

The fuel oil fraction is heated to give a gas and then passed over a catalyst of silicon dioxide (also called silica) and aluminium oxide (also called alumina) at about 600-700 ' C. Cracking can also be carried out at higher temperatures without a catalyst (thermal cracking).

What are the products of the incomplete combustion of methane?

• Carbon monoxide

• Carbon dioxide

• Water

• Hydrogen

• Oxygen

Answer explanation

If there isn't enough air (or oxygen), you get incomplete combustion. This leads to the formation of carbon (soot) or carbon monoxide instead of carbon dioxide.

Which of the following acids is not involved in the formation of acid rains?

• Sulfuric acid

• Carbonic acid

• Nitric acid

• Hydrochloric acid

Answer explanation