Fractional distillation and petrochemicals

Crude oil is a mixture of hydrocarbons.

The majority of hydrocarbons in crude oil belong to one homologous series.

Give the name of this series.

When hydrocarbons undergo combustion, water is produced.

Draw a dot and cross diagram of a molecule of water.

One compound in crude oil contains 0.96 g of carbon atoms combined with 0.32 g of hydrogen atoms.

Calculate the empirical formula of this compound.

(relative atomic masses: C = 12, H = 1.0)

*(d) Crude oil is separated into useful products called fractions using fractional distillation.

Figure 9 shows a fractional distillation column and the fractions kerosene and fuel oil.

Kerosene and fuel oil have different uses depending on their properties.

Describe the properties and uses of kerosene and fuel oil. Include in your answer

• the difference in boiling point

• the difference in viscosity

• the difference in ease of ignition

• their uses and how fuel oil can be converted into kerosene.

Figure 5 shows the structure of one molecule of three different compounds, X, Y and Z.

The molecules of the compounds shown in Figure 5 all contain the same number of carbon atoms.

Give the number of carbon atoms in a molecule of compound X.

Compound X contains carbon and one other element.

Give the name of the other element in compound X.

Which of the compounds in Figure 5 is a hydrocarbon?

Which of the compounds in Figure 5 have the same molecular formula?

Figure 6 shows where fractions are produced in the fractional distillation of crude oil.

Complete the sentences about fractions obtained from crude oil.

The fraction with the smallest molecules is called_........ .

Compared to petrol, the boiling point of kerosene is_........ .

When petrol burns, one product is_........ .

When some impure hydrocarbon fuels are burned, sulfur dioxide is one of the products.

Some sulfur dioxide gas is dissolved in water to form solution W.

When solution W is added to sodium hydroxide solution of pH 12

• the pH changes

• the temperature increases.

Explain how the pH changes and why the temperature increases.

Crude oil is a mixture of hydrocarbons.

Crude oil can be separated into useful fractions by the process of fractional distillation in a fractionating column.

Figure 10 shows a fractionating column, the fractions obtained and the trend in viscosity of the fractions.

Which row shows the correct uses for bitumen, diesel oil and fuel oil?

Explain the trend in the viscosity of the fractions.

Hydrocarbon X was cracked to form one molecule of hexane, C₆H₁₄, and one molecule of alkene Y.

The relative formula mass of Y is 56. The empirical formula of Y is CH₂.

Deduce the molecular formula of hydrocarbon X.

Show your working.

(relative atomic masses: H = 1.0, C = 12)

*(c) Large quantities of methane are used as a fuel.

Figure 11 shows a Bunsen burner.

Methane can be used as fuel for the Bunsen burner.

The air-hole on the chimney of the Bunsen burner can be opened and closed.

Explain the effect of opening and closing the air-hole of the Bunsen burner on the products of combustion of methane and the harm that using large quantities of methane as a fuel can cause.

Figure 5 shows one molecule of a compound obtained from crude oil.

Give the names of the two elements in this molecule.

What is the molecule in Figure 5?

What is the relative formula mass of the compound in Figure 5?

(relative atomic masses: H = 1.0, C = 12)

Crude oil can be separated into different fractions.

Draw one straight line from each fraction to a use of that fraction.

Hydrogen chloride gas and sulfur dioxide gas are dissolved in separate test tubes of water. Blue litmus paper is dipped into each test tube.

State and explain the colour change you would observe in each test tube.

Diesel oil is a mixture of hydrocarbons that can be obtained from crude oil.

State the name of the process used to separate diesel oil from crude oil.

Diesel oil contains alkanes. These alkanes are part of an homologous series.

Which statement about compounds in this homologous series is true?

When fuels such as diesel oil are burned, the high temperatures produced can cause nitrogen and oxygen in the air to form the pollutant nitrogen dioxide.

Complete the balanced equation for the reaction.

N₂ + 2O_{2 ........}

Explain how the greenhouse effect is caused by the gases produced by the complete combustion of diesel oil.

*(e) Diesel oil can contain impurities of sulfur. Burning diesel oil containing impurities of sulfur can result in acid rain. Acid rain is harmful to the environment.

Explain how acid rain is formed and the harm it can do.

Diesel oil is a mixture of hydrocarbons that can be obtained from crude oil.

State the name of the process used to separate diesel oil from crude oil.

Diesel oil contains alkanes. These alkanes are part of an homologous series.

Which statement about compounds in this homologous series is true?

When fuels such as diesel oil are burned, the high temperatures produced can cause nitrogen and oxygen in the air to form the pollutant nitrogen dioxide.

Complete the balanced equation for the reaction.

N₂ + 2O_{2 ........}

Explain how the greenhouse effect is caused by the gases produced by the complete combustion of diesel oil.

Methane is a hydrocarbon fuel.

Complete the word equation for the complete combustion of methane in oxygen.

methane +_........ water +_........

The incomplete combustion of methane can produce carbon and carbon monoxide.

Give the reason why carbon and carbon monoxide are produced in the incomplete combustion of methane.

Crude oil is a complex mixture of hydrocarbons. Crude oil can be separated into useful fractions by fractional distillation.

Figure 7 shows a fractional distillation column and the fractions produced when crude oil is distilled.

Name the fraction in Figure 7 that is used to surface roads.

Name the fraction in Figure 7 that contains hydrocarbons with the lowest boiling point.

When crude oil is fractionally distilled, the demand for some fractions is more than the amount produced.

Figure 8 shows the relative amounts of each fraction in a crude oil and the relative demand for each of these fractions.

Which of the following shows the fractions where the relative demand is greater than the relative amount in the crude oil?

Cracking involves the breaking down of large hydrocarbon molecules into smaller hydrocarbon molecules.

Octane, C₈H₁₈, can be cracked to produce one molecule of ethene, C₂H₄, and one molecule of C_xH₁₄.

Determine the value of x in the molecule of C_xH₁₄.

x =_........

Dodecane is a large hydrocarbon molecule. When one molecule of dodecane is cracked the products are one molecule of octane and one molecule of butene.

dodecane octane + butene

Calculate the maximum mass of octane that could be produced when 340 g of dodecane is cracked in this reaction.

(relative formula masses: dodecane = 170, octane = 114)

mass of octane =_........ g

Most of the fuels used today are obtained from crude oil.

Which statement about crude oil is correct?

Crude oil is separated into several fractions by fractional distillation. Two of these fractions are kerosene and diesel oil.

State a use for each of these fractions.

kerosene_........

diesel oil_........

Figure 8 shows where the fractions kerosene and diesel oil are produced in the fractionating column.

Kerosene is obtained higher up the column than diesel oil. Kerosene and diesel oil fractions have slightly different properties.

Choose a property. State how this property for kerosene compares with the property for diesel oil.

property_........

comparison_........

Figure 9 shows the formulae of a molecule of butane and of a molecule of pentane. Butane and pentane are neighbouring members of the same homologous series.

Explain, using these formulae, why butane and pentane are neighbouring members of the same homologous series.

Butane has the formula C₄H₁₀.

Calculate the mass of carbon in 100 g of butane.

Give your answer to three significant figures.

(relative atomic masses: H = 1.00, C = 12.0; relative formula mass: C₄H₁₀ = 58.0)

You must show your working.

mass of carbon =_........ g

Butane burns completely in air to form carbon dioxide and water.

Write the word equation for this reaction.

Most of the fuels used today are obtained from crude oil.

Which statement about crude oil is correct?

Crude oil is separated into several fractions by fractional distillation. Two of these fractions are kerosene and diesel oil.

State a use for each of these fractions.

kerosene_........

diesel oil_........

Figure 1 shows where the fractions kerosene and diesel oil are produced in the fractionating column.

Kerosene is obtained higher up the column than diesel oil. Kerosene and diesel oil fractions have slightly different properties.

Choose a property. State how this property for kerosene compares with the property for diesel oil.

property_........

comparison_........

Figure 2 shows the formulae of a molecule of butane and of a molecule of pentane. Butane and pentane are neighbouring members of the same homologous series.

Explain, using these formulae, why butane and pentane are neighbouring members of the same homologous series.

Butane has the formula C₄H₁₀.

Calculate the mass of carbon in 100 g of butane.

Give your answer to three significant figures.

(relative atomic masses: H = 1.00, C = 12.0; relative formula mass: C₄H₁₀ = 58.0)

You must show your working.

mass of carbon =_........ g

Crude oil is found in the Earth’s crust.

Which of the statements about crude oil is correct?

The substances ethane, C₂H₆, octane, C₈H₁₈, and pentadecane, C₁₅H₃₂, are all found in crude oil.

These substances

Use a word from the box to complete each of the sentences about the fractional distillation of crude oil.

Each word may be used once, more than once, or not at all.

The separation of crude oil into fractions occurs in a fractional distillation column.

Before crude oil is passed into the column it is_........ .

During the distillation, vapour rises up the column until it is cold enough for the

vapour to form a liquid. The vapour has been_........ .

In January 2015 the United Kingdom produced 850 000 barrels of crude oil per day. 45% of this crude oil was fuel oil.

Calculate the number of barrels of fuel oil present in the 850 000 barrels of crude oil.

Give your answer to two significant figures.

_........ barrels