Fuels Practice Questions

Which of these compounds is a hydrocarbon?

Put a cross ( ☒ ) in the box next to your answer.

☐ A $\mathrm{CO_2}$

☐ B $\mathrm{C_2H_5OH}$

☐ C $\mathrm{C_6H_{14}}$

☐ D $\mathrm{CH_3Cl}$

Crude oil is described as a finite resource.

State what is meant by a finite resource.

As well as being used as fuels, substances from crude oil are used as feedstock for the petrochemical industry.

Give one example of a useful material made from this feedstock.

Crude oil is separated into fractions in a fractionating column.

The table shows some of these fractions and a use for each one.

Fraction	Use
gases	domestic heating and cooking
petrol	fuel for cars
kerosene	fuel for aircraft
diesel oil	...............................................
fuel oil	...............................................
bitumen	surfacing roads and roofs

Complete the table by giving a use for the diesel oil fraction and a use for the fuel oil fraction.

Name the two products formed when butane burns completely.

Butane is obtained from crude oil, which is a non-renewable fossil fuel.

State what is meant by a non-renewable fuel.

Which of these compounds is in the same homologous series as ethane?

Put a cross ( ☒ ) in the box next to your answer.

☐ A $\mathrm{C_3H_6}$

☐ B $\mathrm{C_3H_8}$

☐ C $\mathrm{C_4H_8}$

☐ D $\mathrm{C_5H_{10}}$

Alkanes have the general formula $\mathrm{C_nH_{2n+2}}$.

Deduce the molecular formula of the alkane whose molecules contain 20 carbon atoms.

State what happens to the viscosity of the fractions as you go down the column.

Explain how the hydrocarbons in crude oil are separated into different fractions in the column.

Explain why carbon monoxide is produced when the air inlet is partly blocked.

Write the balanced equation for the incomplete combustion of propane in which carbon monoxide and water are the only products.

Explain why carbon monoxide produced by faulty appliances is dangerous to people in the home.

Explain how burning this fuel oil produces sulfur dioxide.

Explain how the sulfur dioxide released leads to acid rain, and give one problem caused by acid rain.

These alkanes belong to the same homologous series.

Give one feature of an homologous series, other than the compounds having the same general formula.

Explain why the boiling point increases as the number of carbon atoms in the molecule increases.

Use the table to give the name of the alkane that is a gas at a room temperature of $20\,^{\circ}\mathrm{C}$.

Droplets of a colourless liquid form on the inside of the funnel.

Name this liquid and explain why it forms on the funnel.

Give one safety precaution the student should take during this investigation.

The student repeats the investigation with the air hole of the Bunsen burner closed. The flame is now yellow and the funnel becomes coated with a black solid.

Explain these observations.

Most cars today burn petrol in their engines. Some car manufacturers are developing cars that burn hydrogen gas instead.

Evaluate the use of hydrogen, rather than petrol, as a fuel in cars.

Write the balanced equation, including state symbols, for the complete combustion of pentane.

In a poorly ventilated appliance, pentane can burn so that all of the carbon in it forms carbon monoxide.

Write the balanced equation for this reaction. State symbols are not required.

Use the data in the table to explain why the refinery carries out cracking.

One molecule of decane, $\mathrm{C_{10}H_{22}}$, is cracked to form one molecule of propene, $\mathrm{C_3H_6}$, and one molecule of another hydrocarbon.

Deduce the molecular formula of the other hydrocarbon and name the homologous series it belongs to.

Explain why some of the molecules produced by cracking are unsaturated.