Crude oil, hydrocarbons & alkanes

Butane (C₄H₁₀) is an alkane.

Explain why butane is a saturated hydrocarbon.

When butane burns completely in oxygen, carbon dioxide and water are produced.

Give a chemical equation for this combustion reaction.

Incomplete combustion can occur when the oxygen supply is limited.

One product of the incomplete combustion of butane is carbon monoxide.

Give the name of another product of this incomplete combustion.

State why carbon monoxide is poisonous to humans.

C₄H₁₀ exists as two isomers.

State what is meant by the term isomers.

Draw the displayed formula of each isomer.

Explain why hexane (C₆H₁₄) has a higher boiling point than butane (C₄H₁₀).

Crude oil is a mixture of hydrocarbons.

Name the process used to separate crude oil into fractions.

Give one use for the bitumen fraction.

The diagram shows the displayed formula of one of the alkanes in the refinery gases fraction.

Determine the molecular formula of this alkane.

Name this alkane.

Give the general formula of the homologous series of alkanes.

This question is about alkanes and alkenes.

Ethane and ethene each react with bromine, but under different conditions.

Give a reason why ethane does not undergo an addition reaction with bromine.

Complete the equation for the substitution reaction between ethane and bromine, including an essential condition for the reaction.

condition

Give the colour change that occurs when ethene reacts with bromine water.

The diagram shows the displayed formulae of two compounds in the homologous series of alkenes.

Compounds in the same homologous series have the same general formula.

Give two other characteristics of compounds in the same homologous series.

Explain why the alkenes in the diagram are isomers.

Draw the displayed formula of another alkene that is an isomer of these two alkenes.

The reaction used to make poly(ethene) can be represented by this equation.

H H n

Describe the differences between the reactant and the product in this reaction.

Refer to carbon chain length, type of bond and state of matter in your answer.

This question is about methane, CH₄

The diagram shows a Bunsen burner that uses methane.

During combustion, methane reacts with a gas in the air.

Give the name of this gas.

Give the two products of the complete combustion of methane.

During the incomplete combustion of methane, carbon monoxide forms.

Give a reason why carbon monoxide forms during incomplete combustion.

State why carbon monoxide is poisonous.

The equation shows the reaction of methane with bromine.

Give the name of this type of chemical reaction.

This question is about alkanes and alkenes.

The alkane C₄H₁₀ exists as two isomers.

State what is meant by the term isomers.

Draw the displayed formulae for the two isomers of C₄H₁₀

Ethane (C₂H₆) can react with bromine.

State the condition needed for ethane to react with bromine.

Complete the equation for this reaction.

Give the name for this type of reaction.

Explain why ethane is described as a saturated compound.

State what you would observe when ethane and ethene are added separately to two samples of bromine water.

ethane

ethene

Explain why straight‑chain alkenes always have the same empirical formula, but straight‑chain alkanes have different empirical formulae.

Refer to the molecular formulae of the alkanes C₂H₆ and C₄H₁₀ in your answer.

An organic compound has this percentage composition by mass.

C = 19.2 % H = 4.0 % O = 12.8 % Br = 64.0 %

Calculate the empirical formula of this compound.

This question is about alkanes.

An alkane has the structural formula CH₃CH₂CH₂CH₃

Give the missing information for this alkane.

There are two isomers of C₄H₁₀

State what is meant by the term isomers.

Draw the displayed formula of each isomer of C₄H₁₀

Isomer 1
Isomer 2

Methane reacts with bromine to form bromomethane and one other product.

Give the formula of the other product.

What is the name of this type of reaction?

State the condition needed for this reaction to occur.

When ethane (C₂H₆) burns in a plentiful supply of air, carbon dioxide and water are formed.

Give a chemical equation for this reaction.

When the air supply is limited, incomplete combustion occurs.

Explain why a gas formed by incomplete combustion can cause a problem for humans.

This question is about organic compounds.

Give the total number of atoms in one molecule of methanoic acid.

Determine the relative molecular mass (M_r) of methanoic acid.

Explain why methanoic acid is not a hydrocarbon.

The atoms in methanoic acid are held together by covalent bonds.

State, in terms of electrostatic attractions, what is meant by the term covalent bond.

Draw a dot‑and‑cross diagram to show the bonding in a molecule of methanoic acid.

Show only the outer electrons of each atom.

Calculate the empirical formula of the organic compound with this composition by mass.

C = 52.2% H = 13.0% O = 34.8%

Give a reason why compound X is not a hydrocarbon.

Give the letter of the compound that is a saturated hydrocarbon with the empirical formula CH₂

Give the letter of the compound that produces nine moles of water when one mole undergoes complete combustion.

Give the structural formula of compound Y.

Explain why compounds W and Y are isomers.

Compound Z reacts with bromine in the presence of ultraviolet radiation.

Write a chemical equation for this reaction.

What is the name for this type of reaction?

Describe how the combustion of sulfur-free petrol in a car engine produces gases that can cause acid rain.

Do not refer to carbon dioxide in your answer.

This question is about alkanes and alkenes.

The alkane C₅H₁₂ has three isomers.

State what is meant by the term isomers.

Calculate the relative formula mass (M_r) of C₅H₁₂

This is the displayed formula of one of the isomers.

H H H H H

Give the name of this isomer.

Draw the displayed formulae of the other two isomers.

Isomer 1
Isomer 2

Ethane (C₂H₆) and ethene (C₂H₄) both react with bromine.

Describe the differences in the reactions of ethane and ethene with bromine.

Refer to the conditions, the products and the types of reaction involved.

This question is about alkanes.

Which of these is the molecular formula of an alkane?

Which of these has the same empirical formula and molecular formula?

In the presence of ultraviolet radiation, methane reacts with bromine to form bromomethane and hydrogen bromide.

State the name of this type of reaction.

Give a chemical equation for this reaction.

One mole of an alkane burns completely in oxygen.

The equation represents the reaction.

The numbers x, y and z are used to balance the equation.

The complete combustion of one mole of the alkane produces 220 g of carbon dioxide and 108 g of water.

Calculate the values of y and z.

[M_r of CO₂ = 44 M_r of H₂O = 18]

Determine the molecular formula of the alkane and the value of x.

When an alkane burns in a limited supply of air, incomplete combustion occurs.

Explain why incomplete combustion of an alkane could be harmful to humans.

Give the letter of a compound not shown as a displayed formula.

Give the letter of a saturated compound with the general formula C_nH_2n

Name compound E.

Explain why compound A and compound D are isomers.

Compound F reacts with bromine in the presence of ultraviolet radiation.

Complete the equation for the reaction.

Give the name of this type of reaction.

Another compound, G, has this percentage composition by mass.

C = 37.8 % H = 6.3 % C l = 55.9 %

Show by calculation that the empirical formula of compound G is C₂H₄Cl

The relative formula mass (M_r) of G is 127

Determine the molecular formula of G.

Compound E is used to make an addition polymer.

Give one problem caused by the disposal of addition polymers.

This question is about the unsaturated hydrocarbon, ethene.

The displayed formula of ethene is

State the meaning of the term hydrocarbon.

Give the reason why ethene is described as unsaturated.

Ethene is bubbled through bromine water until there is no further colour change.

Which of these is the appearance of the solution formed?

Ethanol is produced industrially by the reaction between ethene and steam.

The equation for the reaction is

State the temperature and pressure used in this reaction.

temperature

pressure

Give the molecular formula of ethanol.

Crude oil is a mixture of hydrocarbons.

This passage is about the industrial separation of crude oil.

Complete the passage by adding the missing words.

Crude oil is_........ to form vapour.

The vapour is passed through a_........ column.

The refinery gases are collected at the top of the column because they have low

Bitumen is collected at the bottom of the column.

Give one use of bitumen.

One of the hydrocarbons in crude oil is an alkane with this structural formula.

Give the name of this alkane.

Calculate the relative molecular mass (M_r) of this alkane.

Catalytic cracking is used to convert long-chain alkanes into shorter-chain alkanes.

Give the name of the catalyst and the temperature used in catalytic cracking.

Catalytic cracking also produces alkenes.

Decane (C₁₀H₂₂) can undergo cracking to give C₄H₁₀ and two different alkenes.

Complete the equation for this cracking process.

Crude oil is a mixture of organic compounds.

Most of these compounds are members of the same homologous series.

State the name of this homologous series.

An industrial process is used to separate crude oil into fractions.

The process depends on a difference in a property of the fractions.

What is this property?

The boxes give some uses of fractions and some names of fractions.

Draw one straight line from each use to its correct fraction.

Fuels obtained from the fractions may contain impurities.

Explain how the combustion of a common impurity in fuels may cause an environmental problem.

Some of the fractions contain long-chain molecules which are not very useful.

Give the name of the process used to convert long-chain molecules into more useful shorter-chain molecules.

Give the catalyst and temperature used in the industrial process to convert long-chain molecules into shorter-chain molecules.

When C₁₃H₂₈ is used in this process, three different molecules are formed.

Complete the equation for this reaction.

A sample of a gaseous hydrocarbon, X, has a volume of 600 cm³ at room temperature and pressure (rtp).

Calculate the amount, in moles, of hydrocarbon X in the sample.

[molar volume of a gas = 24 000 cm³ at rtp]

The mass of the sample of hydrocarbon X is 1.45 g.

Show that the relative molecular mass (M_r) of X is 58

Hydrocarbon X is an alkane.

Show that the molecular formula of X is C₄H₁₀

Give the displayed formula of the branched‑chain isomer of hydrocarbon X.

This question is about alkenes and alkanes.

Complete the table by giving the missing information about the alkene with the molecular formula C₃H₆

Alkenes are unsaturated compounds.

State what is meant by the term unsaturated.

Describe a test to show that a compound is unsaturated.

When the alkane methane reacts with chlorine, the products are chloromethane (CH₃Cl) and hydrogen chloride gas.

Give a chemical equation for this reaction.

What is the name of this type of reaction?

State the condition needed for this reaction to occur.

When ethane reacts with chlorine, one of the products of the reaction has the formula C₂H₄Cl₂

There are two isomers with this formula.

State what is meant by the term isomers.

Draw the displayed formulae of the two isomers with the formula C₂H₄Cl₂

The diagram shows the displayed formula of the organic compound methanol, CH₃OH

Determine the number of atoms in one molecule of methanol.

State why methanol is not a hydrocarbon.

The atoms in methanol are held together by covalent bonds.

State what is meant by the term covalent bond.

Draw a dot-and-cross diagram to show the bonding in a molecule of methanol.

Show only the outer electrons of each atom.

Another organic compound has the percentage composition by mass

C = 38.7% H = 9.7% O = 51.6%

Calculate the empirical formula of this compound.

The relative molecular mass (M_r) of the compound is 62

Determine the molecular formula of the compound.

The boxes show the displayed formulae of six organic compounds, P, Q, R, S, T and U.

Use the letters P, Q, R, S, T and U to answer these questions.

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

Give the letter of the compound that is not a hydrocarbon.

Give the letters of the two compounds that have the same empirical formula.

Give the letter of the compound that is used to manufacture poly(propene).

Describe a test that can be used to distinguish between compounds Q and T.

result with compound Q_........

result with compound T_........

Compounds P, Q and R are members of the same homologous series.

Give two characteristics of a homologous series.

This is the displayed formula of an alkene, V.

Give the name of alkene V.

Draw the displayed formula of another alkene that is an isomer of alkene V.

An organic compound has the percentage composition by mass

C = 36.36% H = 6.06% F = 57.58%

Show that the empirical formula of the compound is CH₂F

The relative molecular mass (M_r) of the compound is 66.

Determine the molecular formula of the compound.

Crude oil is a mixture of hydrocarbons.

Name the process used to separate crude oil into fractions.

Give one use of the kerosene fraction.

One of the hydrocarbons in the refinery gas fraction is an alkane with the structural formula CH₃CH₂CH₂CH₃

Give the name of this alkane.

Calculate the relative molecular mass (M_r) of this alkane.

One of the alkanes in the gasoline fraction has the displayed formula

H H H H H H H

Determine the molecular formula of this alkane.

Give the general formula for the alkanes.

Catalytic cracking is used to convert long‑chain alkanes into shorter‑chain alkanes.

Name the catalyst used in catalytic cracking.

Explain why it is necessary to convert long‑chain alkanes into shorter‑chain alkanes.

Catalytic cracking also produces alkenes.

C₁₁H₂₄ can undergo cracking to give pentane (C₅H₁₂) and two different alkenes.

Complete the equation for this cracking reaction.