Organic chemistry

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.

Methanol, CH₃OH, is the first member of the homologous series of alcohols.

Give two characteristics of a homologous series.

Methanol is heated with potassium dichromate(VI) and one other reagent.

The methanol is oxidised to methanoic acid, HCOOH

Give the formula of the other reagent.

Give the colour change that occurs during the reaction.

Draw the displayed formula for methanol and for methanoic acid in the boxes.

methanol
methanoic acid

Methanol reacts with methanoic acid to form an ester.

Complete the equation for this reaction.

The structural formula of an ester is CH₃COOCH₂CH₂CH₂CH₃

What is the name of this ester?

Deduce the molecular formula of this ester.

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 unsaturated hydrocarbons.

Ethene (C₂H₄) is a member of the homologous series of alkenes.

Give two characteristics of a homologous series.

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

Show outer electrons only.

Propene (C₃H₆) is another member of the homologous series of alkenes.

State why the empirical formula of all alkenes in this homologous series is CH₂

Propene can be polymerised to form poly(propene).

Draw the displayed formula of propene and the repeat unit of poly(propene).

propene
repeat unit of poly(propene)

This is the structural formula of another hydrocarbon compound.

Give the molecular formula and the empirical formula of this compound.

molecular formula

empirical formula

Explain why this compound is an unsaturated hydrocarbon.

Describe a test to show that this hydrocarbon is unsaturated.

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.

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.

Hand sanitiser liquids are used regularly to reduce the spread of infections.

Three compounds P, Q and R are often present in these liquids.

What type of formula is shown for P?

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

Give two properties of a homologous series.

Name the homologous series that contains compounds P, Q and R.

Give the name of compound Q.

Diols and dicarboxylic acids react together in polymerisation reactions to form polyesters.

Explain the name given to the type of polymerisation that occurs in these reactions.

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.

The diagram shows some important conversion processes used in the oil industry.

Describe how kerosene is produced from crude oil in process 1.

C₁₂H₂₆ is present in kerosene.

In process 2, C₁₂H₂₆ is cracked to produce two molecules of ethene and one molecule of another hydrocarbon.

Complete the equation for the cracking of C₁₂H₂₆

Explain why cracking is a useful process in the oil industry.

This is the equation for one of the reactions that may occur during process 3.

H H

C l C l

What is the name of this type of reaction?

Explain why the disposal of polymers such as poly(chloroethene) is difficult.

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.

An organic compound has this percentage composition by mass.

C = 40 % H = 6.7 % O = 53.3 %

Show that the empirical formula of the compound is CH₂O

Draw the structural formula of a compound with the molecular formula C₂H₄O₂

Methanoic acid (HCOOH) reacts with sodium carbonate solution to give three products.

Complete the equation for this reaction.

2HCOOH + Na₂CO_{3 ........} +_........ +_........

State what you would observe in this reaction.

Methanoic acid also reacts with propanol to form an ester.

The equation for the reaction is

Give the name of the ester that forms.

State what is meant by the symbol.

When this reaction occurs in a sealed container, the reaction can reach dynamic equilibrium.

Give one characteristic of a reaction at dynamic equilibrium.

A polyester forms when butanedioic acid reacts with ethanediol.

The diagram shows the repeat unit of the polyester that forms.

O O

Give the name of this type of polymerisation.

Draw the structural formulae of the two monomers used to make this polyester.

This question is about alcohols, carboxylic acids and esters.

Ethanol can be manufactured by the fermentation of a solution of glucose.

Write a word equation for this reaction.

State the substance that needs to be added for the reaction to occur.

State two conditions needed for this reaction.

In the presence of an acid catalyst, ethanoic acid is heated with butanol to form an ester.

Which of these is the formula of the ester?

State how you would know that an ester has formed.

Give one use of an ester.

Aspirin is a compound used to reduce pain.

Aspirin contains a carboxylic acid functional group and an ester functional group.

State what is meant by the term functional group.

This is the structural formula of aspirin.

O O

Draw a circle around the carboxylic acid functional group.

Aspirin has this percentage composition by mass.

C = 60.00 % H = 4.44 % O = 35.56 %

Show by calculation that the empirical formula of aspirin is C₉H₈O₄

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.

Organic compounds can exist as isomers.

Explain what is meant by the term isomers.

Organic compound Q reacts with bromine, without the presence of ultraviolet radiation, to form the compound C₄H₈Br₂

Draw the displayed formulae of two isomers of Q.

An acrylic polymer can be formed from molecules with this structure.

A student describes the molecule as an unsaturated hydrocarbon.

Explain whether this is a correct description.

Name the type of polymerisation that occurs in the formation of the polymer.

Complete the equation for the polymerisation reaction.

Octane is a compound in petrol.

The equation for the complete combustion of octane is

The fuel tank of a car contains 50.0 dm³ of octane.

Calculate the mass, in kg, of carbon dioxide formed if all the octane in the fuel tank undergoes complete combustion.

[mass of 1 dm³ of octane = 700 g]

State an environmental problem caused by carbon dioxide.

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 table shows the molecular formulae of six organic compounds, A, B, C, D, E and F.

Explain which homologous series compound B belongs to.

Give the letter of the compound that has the same empirical formula as its molecular formula.

Compound F exists as two isomers.

Explain what is meant by the term isomers.

Include the structures of the two isomers of compound F in your answer.

Describe how compound D can be obtained from crude oil using the industrial process of fractional distillation.

Compound C can be used to make a polymer.

State the type of polymer formed from compound C.

Name the polymer formed from compound C.

Draw the structure of this polymer.

Include the displayed formula of the repeat unit.

Alcohols contain the functional group —OH

Give the structural formula of the alcohol that contains one carbon atom.

Ethanol (C₂H₅OH) is an alcohol that can be obtained from glucose (C₆H₁₂O₆).

Name the process that converts glucose into ethanol.

Explain why this process is carried out in the absence of air and at a temperature below 40C.

The table gives information about some organic compounds in the same homologous series.

Complete the table by giving the missing information.

Name the homologous series that contains these compounds.

The compounds in the table can react with alcohols to form esters.

When preparing esters, a small amount of concentrated sulfuric acid is also used.

State the purpose of the acid.

Draw the displayed formula of the ester that forms when propanoic acid reacts with ethanol.

Esters have particular uses that depend on their properties.

Give an example of a property and use of esters.

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.

This question is about alkenes and polymers.

Ethene (C₂H₄) can be represented by different types of formula.

Complete the table by giving the missing information.

Ethene is a member of the homologous series of alkenes.

All members of the same homologous series have the same general formula.

Give two other characteristics of a homologous series.

Ethene is used to make poly(ethene).

State the type of polymerisation used to form poly(ethene).

Complete the equation for the polymerisation of ethene.

Poly(ethene) is used to make plastic bags.

Corn starch from plants can also be used to make polymers for plastic bags.

The table gives some information about poly(ethene) and polymers made from corn starch.

Use the information in the table and your knowledge to discuss the advantages and disadvantages of using poly(ethene) to make plastic bags.

The diagram shows the repeat unit of another polymer.

Draw the displayed formula of the monomer used to make this polymer.

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.

This question is about some Group 2 elements and their compounds.

Calcium reacts with water to produce calcium hydroxide and hydrogen gas.

Give the word equation for this reaction.

State two observations that would be made during this reaction.

Describe how a pure, dry sample of the insoluble salt, barium sulfate, could be made from the two solids sodium sulfate and barium chloride.

Give an ionic equation for the reaction that occurs.

Include state symbols in your equation.

When magnesium nitrate is heated, magnesium oxide, nitrogen dioxide and oxygen form.

The equation for the reaction is

What is the name for this type of reaction?

Calculate the total volume, in dm³, of gas produced at rtp when 7.7 g of magnesium nitrate completely reacts.

[Assume that the molar volume of a gas at rtp is 24 dm³]

[M_r of Mg(NO₃)₂ = 148]

Give your answer to two significant figures.