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GCSE Questions and Answers Organic Chemistry

6 consecutive CCEA GCSE Chemistry papers: 2002-7

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2002, Paper 2 4a) Ethene, C 2 H 4 , is the first member of a homologous series of hydrocarbons called the alkenes.

(i) What is a hydrocarbon?

_____________________________ ___________________________ [2]

4a) Ethene, C 2 H 4 , is the first member of a homologous series of hydrocarbons called the alkenes.

(i) What is a hydrocarbon?

Only [1] contain carbon and hydrogen [1] atoms

(ii) Complete the table below giving the molecular formula of propene and the physical states of both alkenes at room temperature and pressure.

Name of Alkene

Ethene

Molecular formulae Physical state at room temperature and pressure

C 2 H 4 Propene

(ii) Complete the table below giving the molecular formula of propene and the physical states of both alkenes at room temperature and pressure.

Name of Alkene

Ethene

Molecular formulae Physical state at room temperature and pressure

C 2 H 4 Gas [1] Propene C 3 H 6 [1] Gas [1]

(iii) Draw the structure of ethene showing all bonds.

[2]

(iii) Draw the structure of ethene showing all bonds.

[2]

(iv) What would you observe if some bromine water was added to a sample of ethene?

_____________________________ ___________________________ [2] (v) Name the organic product formed when ethene reacts with water.

___________________________ [1]

What would you observe if some bromine water was added to a sample of ethene?

Yellow/orange/brown [1] to colourless [1] (decolourises = [1]) (v) Name the organic product formed when ethene reacts with water.

Ethanol [1] (Accept C 2 H 5 OH)

b) Addition polymerisation is an important industrial reaction of alkenes. Vinyl chloride is an alkenes commonly used for polymerisation.

i) Write an equation for the formation of the polymer formed from vinyl chloride.

[4]

b) i) Addition polymerisation is an important industrial reaction of alkenes. Vinyl chloride is an alkenes commonly used for polymerisation.

Write an equation for the formation of the polymer formed from vinyl chloride. [4]

(ii) Give two uses of the polymer formed from vinyl chloride.

1. ___________________________ 2. ________________________ [2] c) Give one reason why it is important to recycle polymers.

_____________________________ __________________________ [1]

(ii) Give two uses of the polymer formed from vinyl chloride.

Clothing/seat covers/records/window frames or other correct. Any two [2] c) Give one reason why it is important to recycle polymers.

Save resources/limited dumping / landfill / reduce toxic fumes on burning. [1]

2003, Paper 2 6a) Butane is a hydrocarbon fuel used in many small lighters in which the gas is ignited using a spark from a flint.

(i) What is meant by the term “hydrocarbon”?

___________________________ [2] (ii) To which homologous series does butane belong?

___________________________ [1]

(i) What is meant by the term “hydrocarbon”?

Contains carbon and hydrogen atoms [1] only [1] (ii) To which homologous series does butane belong?

Alkanes [1]

(iii) Draw the structural formula of butane showing all the bonds in the compound. [2]

(iii) Draw the structural formula of butane showing all the bonds in the compound. [2] H H H H I I I I H – C – C – C – C – H I I I I H H H H

b) Petrol is a hydrocarbon fuel burnt in car engines.

It is obtained from crude oil and consists mainly of octane.

(i) Name the two products formed when octane burns completely in a plentiful supply of air.

____________________

b) Petrol is a hydrocarbon fuel burnt in car engines It is obtained from crude oil and consists mainly of octane.

(i) Name the two products formed when octane burns completely in a plentiful supply of air.

Carbon dioxide [1] water/steam [1]

Keep the problems with oil in mind as well!

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(ii) If a car engine is not serviced correctly the octane does not burn completely. Name the poisonous product formed in this reaction.

___________________________ [1] (iii) Name the industrial method used to obtain petrol from crude oil.

___________________________ [1]

(ii) If a car engine is not serviced correctly the octane does not burn completely. Name the poisonous product formed in this reaction.

Carbon monoxide [1] (iii) Name the industrial method used to obtain petrol from crude oil.

Fractional [1] distillation [1]

Fractional Distillation (Fractionation) of Crude Oil.

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c) Liquid octane can be thermally cracked in the laboratory using the apparatus shown below.

(i) Why is it possible to collect the products over water?

_______________________________ [1] (ii) What is meant by the term “cracking”?

_______________________________ [2]

(i) (ii) Why is it possible to collect the products over water?

Not very soluble in water/insoluble [1] What is meant by the term “cracking”?

Breaking down large molecules [1] into smaller molecules [1]

(iii) When octane, C 8 H 18 , is cracked, ethene and one other hydrocarbon is produced. Write a balanced, symbol equation for the cracking of octane.

______________________________ ___________________________ [2]

(iii) When octane, C 8 H 18 , is cracked, ethene and one other hydrocarbon is produced. Write a balanced, symbol equation for the cracking of octane.

C 8 H 18 → C 2 H 4 + C 6 H 14 [2]

(iv) Ethene is an alkene. Describe a chemical test which could be used to prove that an alkene was produced. State the result of the test.

_________________________________ _________________________________ _______________________________ [3]

(iv) Ethene is an alkene. Describe a chemical test which could be used to prove that an alkene was produced. State the result of the test.

(bubble into) bromine water [1] red brown to [1] colourless / decolourised [1]

d) “Gasochol” is an alternative fuel which contains up to 20% ethanol. The ethanol is produced by the fermentation of sugar cane.

(i) Draw the structural formula of ethanol showing all the bonds in the compound.

[2]

(ii) Write a balanced, symbol equation for the combustion of ethanol in a plentiful supply of air.

_______________________________ [2] (iii) Describe how ethanol is produced by fermentation.

______________________ __________________________________ _______________________________ [4]

(ii) Write a balanced, symbol equation for the combustion of ethanol in a plentiful supply of air.

C 2 H 5 OH + 3O 2 → 2CO 2 + 3H 2 O[2] (iii) Describe how ethanol is produced by fermentation.

The key points of this answer are: sugar/grapes, yeast, exclude air, control temperature, CO 2 (Max [4] from [5]) produced

(iv) Give one other use of ethanol, apart from as a fuel.

___________________________ [1]

(iv) Give one other use of ethanol, apart from as a fuel.

Alcoholic beverage / solvent [1]

2004, Paper 2 1 Ethanol is an important carbon compound. It is the “active ingredient” in alcoholic drinks and is often just called “alcohol”.

a)(i) Give the molecular formula for ethanol.

_______________________________ [1]

1 Ethanol is an important carbon compound. It is the “active ingredient” in alcoholic drinks and is often just called “alcohol”.

a)(i) Give the molecular formula for ethanol .

C 2 H 5 OH [1]

(ii) Draw the full structural formula of ethanol.

[2]

(ii) Draw the full structural formula of ethanol.

[2] all bonds present = [2] 1 bond missing = [1] more than one bond missing = [0]

b) Ethanol can be produced by the fermentation of sugar solutions.

(i) What must be added to a sugar solution for fermentation to occur?

_______________________________ [1] (ii) Give two other conditions which are necessary for fermentation to take place.

_______________________________ _______________________________ [2]

b) Ethanol can be produced by the fermentation of sugar solutions.

(i) What must be added to a sugar solution for fermentation to occur?

Yeast [1] (ii) Give two other conditions which are necessary for fermentation to take place.

Warm (20°C ≤ 50°C) [1] exclusion of air [1]

(iii) Name the other product of this fermentation.

_______________________________ [1] (iv) What technique can be used to make the dilute solution of ethanol produced more concentrated?

_______________________________ [1]

(iii) Name the other product of this fermentation.

Carbon dioxide [1] (iv) What technique can be used to make the dilute solution of ethanol produced more concentrated?

Distillation [1]

c) Ethanol has many uses. Some countries, including Brazil, use ethanol as a fuel for cars.

(i) Write a balanced symbol equation for the combustion of ethanol.

_______________________________ [1] (ii) Give one advantage of ethanol as a fuel compared to the alkanes.

_______________________________ [1]

c) Ethanol has many uses. Some countries, including Brazil, use ethanol as a fuel for cars.

(i) Write a balanced symbol equation for the combustion of ethanol.

C 2 H 5 OH + 3O 2 → 2CO 2 + 3H 2 O [1] (ii) Give one advantage of ethanol as a fuel compared to the alkanes.

It is a clean fuel/renewable [1]

(iii) The combustion of ethanol is an exothermic reaction. What is meant by the term exothermic?

_______________________________ _______________________________ [2] (iv) Explain in terms of bonds broken and bonds made why a reaction such as the combustion of ethanol is exothermic.

_______________________________ _______________________________ [5]

(iii) The combustion of ethanol is an exothermic reaction. What is meant by the term exothermic?

Gives out [1] heat [1] [2] (iv) Explain in terms of bonds broken and bonds made why a reaction such as the combustion of ethanol is exothermic.

Breaking bonds requires heat energy [1] in reactants [1]. Formation of new bonds releases energy [1] in products [1]. More energy is given out than is taken in.

[5]

d) Ethanol reacts with ethanoic acid to form an ester.

(i) Briefly describe the conditions necessary to carry out this reaction on a test tube scale.

_______________________________ _______________________________ _______________________________ [3]

d) Ethanol reacts with ethanoic acid to form an ester.

(i) Briefly describe the conditions necessary to carry out this reaction on a test tube scale.

A few drops of concentrated [1] sulphuric acid [1] are added and the mixture is warmed [1] (for a few minutes) [3]

(ii) Name the ester formed and draw its full structural formula.

_______________________________ [1] Structural Formula [2]

(ii) Name the ester formed and draw its full structural formula.

Ethyl ethanoate [1] Structural Formula all bonds present = [2] 1 bond missing = [1] more than one bond missing = [0]

(iii) Give one use for this ester.

_______________________________ [1] e) Alcohol is a drug and is addictive. Excessive intake over an extended period of time can damage vital organ s in the body. What do you understand by the term “ safe drinking limit”?

_______________________________ _______________________________ [1]

(iii) Give one use for this ester.

Solvent/flavourings [1] e) Alcohol is a drug and is addictive. Excessive intake over an extended period of time can damage vital organ s in the body. What do you understand by the term “ safe drinking limit”?

Implies drink in moderation [1]

2005, Paper 2 6a) alkanes and alkenes are two distinct homologous series of hydrocarbons. Propane is an alkane and propane is an alkane. Alkanes are described as saturated.

(i) What is meant by the term homologous series?

_______________________________ _______________________________ [3]

6a) alkanes and alkenes are two distinct homologous series of hydrocarbons. Propane is an alkane and propane is an alkane. Alkanes are described as saturated.

(i) What is meant by the term homologous series?

Same general formula/same type of molecule [1] increase in size/increase in carbon chain/increase by CH 2 unit [1] same chemical properties [1] gradation in physical properties [1] (Max [3])

(ii) What is hydrocarbon?

_______________________________ _______________________________ [2] (iii) What is meant by the term saturated?

_______________________________ _______________________________ [2]

(ii) What is hydrocarbon?

Only [1] contains carbon and hydrogen atoms [1] (iii) What is meant by the term saturated?

No [1] double/triple bonds [1] (or only [1] single [1] bonds) [2]

(iv) Give the molecular and structural formulae of propane and propene in the table below.

Hydrocarbon Molecular formula Structural formula

Propane Propene

(iv) Give the molecular and structural formulae of propane and propene in the table below.

Hydrocarbon Molecular formula Structural formula

Propane C 3 H 8 [1] Propene C 3 H 6 [1]

(v) What chemical test is used to distinguish between propane and propene? Give the observations you would make.

Test: ___________________________ [1] Result with propane: ______________ _______________________________ Result with propene: ______________ _______________________________ [3]

(v) What chemical test is used to distinguish between propane and propene? Give the observations you would make.

Test: Bromine water [1] Result with propane: No Change [1] Result with propene: orange/red-brown/ brown [1] to colourless [1]

b) Crude oil is a complex mixture of hydrocarbons which can be separated into simpler mixtures. The process of thermal cracking is used on some of the hydrocarbon mixtures.

(i) What is the name of Process 1 in which crude oil is separated into simpler mixtures of hydrocarbons?

_______________________________ [2] (ii) Explain what happens to the hydrocarbons when they undergo thermal cracking.

_______________________________ _______________________________ _______________________________ [2]

(i) What is the name of Process 1 in which crude oil is separated into simpler mixtures of hydrocarbons?

Fractional [1] distillation [1] [2] (ii) Explain what happens to the hydrocarbons when they undergo thermal cracking.

Larger/longer [1] molecules broken into smaller/shorter [1] ones [2]

(iii) Explain why thermal cracking is only used on some hydrocarbon mixtures.

_______________________________ _______________________________ _______________________________ [1]

(iii) Explain why thermal cracking is only used on some hydrocarbon mixtures.

Longer chains fewer uses/some fractions are so useful they do not need to be cracked/shorter chains more uses [1]

c) Polythene or poly(ethene) is a polymer formed when ethene molecules react with other ethene molecules.

(i) Write a structural equation to show the formation of polyethene from ethene.

_______________________________ _______________________________ _______________________________ _______________________________ [4]

c) Polythene or poly(ethene) is a polymer formed when ethene molecules react with other ethene molecules.

(i) Write a structural equation to show the formation of polyethene from ethene. [4]

(ii) Give one use of polythene.

_______________________________ [1] (iii) Polymers like polythene can be disposed of in landfill sites or by incineration. Give one problem associated with each method of disposal.

Incineration: _______________________ _______________________________ [1] Landfill: ___________________________ _______________________________ [1]

(ii) G ive one use of polythene.

plastic bags / plastic bottles [1] (iii) Polymers like polythene can be disposed of in landfill sites or by incineration. Give one problem associated with each method of disposal.

Incineration: CO 2 produced / greenhouse effect / toxic fumes / air pollution [1] Landfill: land waste / non-biodegradable/ eyesore / water pollution / smell [1]

d) The structure below represents part of another polymer.

(i) What is the name of this polymer?

_______________________________ [1] (ii) Draw the structural formula of the monomer from which this polymer is formed.

[1]

(i) What is the name of this polymer?

Polystyrene [1] (ii) Draw the structural formula of the monomer from which this polymer is formed.

[1]

3 2006, Paper 1 Organic compounds are used in medicine and first aid.

a) (i) One of the first anaesthetics to be used in surgery was ethene. However, ethene is flammable and halothane, CF 3 CHBrCl, is now used instead.

Draw the structural formula of ethene.

3 Organic compounds are used in medicine and first aid.

a) (i) One of the first anaesthetics to be used in surgery was ethene. However, ethene is flammable and halothane, CF 3 CHBrCl, is now used instead.

Draw the structural formula of ethene.

1 bond missing = [1] More than 1 bond missing = [0]

(ii) Describe a chemical test which could be used to show that ethene is unsaturated. Give the observations which would occur.

Test: ___________________________ [1] Observations: ______________________ _______________________________ [2]

(ii) Describe a chemical test which could be used to show that ethene is unsaturated. Give the observations which would occur.

Test: Add bromine (water) colourless/decolourises [1] [1] Observations: Red brown [1]. Changes to [2]

(iii) Explain why halothane is not a hydrocarbon.

_______________________________ _______________________________ [1] (iv) Write a balanced symbol equation for the burning of ethene in excess air.

_______________________________ [3]

(iii) Explain why halothane is not a hydrocarbon.

Halothane contains other elements / contains F, Cl, Br / halogen [1] (iv) Write a balanced symbol equation for the burning of ethene in excess air.

C 2 H 4 [1] + 3O 2 → 2CO 2 + 2H 2 O [3] [1] + [1] for balancing

(v) At room temperature and pressure, what is the physical state of ethene?

_______________________________ [1]

(v) At room temperature and pressure, what is the physical state of ethene?

Gas [1]

b) Hip and shoulder joints which have been damaged by arthritis can be replaced during surgery by a metal ‘bone’ which fits into a polythene cup. Polythene is a polymer made from ethene.

(i) State one property of polythene which makes it suitable for this use.

_______________________________ [1]

b) Hip and shoulder joints which have been damaged by arthritis can be replaced during surgery by a metal ‘bone’ which fits into a polythene cup. Polythene is a polymer made from ethene.

(i) State one property of polythene which makes it suitable for this use.

Unreactive / durable / strong / easily moulded / low density / light / non toxic[1]

(ii) What is meant by the term polymer?

_______________________________ _______________________________ [2] (iii) Draw the structure of polythene.

(ii) What is meant by the term polymer?

Monomers / small molecules / repeating unit [1] bond / join / form a (long) chain[1] (iii) Draw the structure of polythene.

Correct structure with carbon-carbon single bond [1] repeat indicated [1]

c) Surgical spirit is used to sterilise surfaces and to cleanse cuts in the skin. It contains ethanol and a small amount of methanol.

(i) Draw the structural formula of ethanol.

c) Surgical spirit is used to sterilise surfaces and to cleanse cuts in the skin. It contains ethanol and a small amount of methanol.

(i) Draw the structural formula of ethanol.

1 bond missing = [1] more than 1 bond missing = [0]

(ii) The ethanol in surgical spirit is produced in industry from ethene. Write a balanced symbol equation for the production of ethanol from ethene.

_______________________________ [2]

(ii) The ethanol in surgical spirit is produced in industry from ethene. Write a balanced symbol equation for the production of ethanol from ethene.

C 2 H 4 + H 2 O → C 2 [1] H 5 OH [1] [2]

(iii) Alcoholic drinks also contain ethanol, which is produced by fermentation. Explain the process of fermentation.

_______________________________ _______________________________ [3]

(iii) Alcoholic drinks also contain ethanol, which is produced by fermentation. Explain the process of fermentation.

Sugar / fruit [1]* under the action of yeast [1]* form carbon dioxide and alcohol [1], warm [1] conditions, aqueous conditions [1] in the absence of air [1]. * Essential[3]

d) In first aid ethanoic acid is used to treat wasp stings which are alkaline.

(i) Draw the structural formula of ethanoic acid.

d) In first aid ethanoic acid is used to treat wasp stings which are alkaline.

(i) Draw the structural formula of ethanoic acid.

1 bond missing = [1] More than 1 bond missing = [0]

(ii) State another use of ethanoic acid.

_______________________________ [1] (iii) Ethyl ethanoate is formed when ethanoic acid reacts with ethanol. Draw the structural formula of ethyl ethanoate.

(ii) (iii) State another use of ethanoic acid.

Pickling/preservative/flavouring/ vinegar/cleaning [1] Ethyl ethanoate is formed when ethanoic acid reacts with ethanol. Draw the structural formula of ethyl ethanoate.

1 bond missing = [1] More than 1 bond missing = [0]

2007, Paper 1 2a) Most of our fuels come from animals and plants that lived millions of years ago. Fuels formed in this way are called fossil fuels and they are non-renewable fuels. Propane is a non-renewable fuel.

(i) Name the homologous series of organic compounds to which propane belongs.

_______________________________ [1] (ii) Write a balanced symbol equation to show the complete combustion of propane.

_______________________________ [3]

(i) Name the homologous series of organic compounds to which propane belongs.

Alkanes [1] (ii) Write a balanced symbol equation to show the complete combustion of propane.

C 3 H 8 + 5O 2 → 3CO 2 + 4H 2 O [3]

(iii) Explain what you understand by the term non-renewable.

_______________________________ _______________________________ [2]

(iii) Explain what you understand by the term non-renewable.

Cannot be replaced/renewed [1] in a relatively short period of time [1] by earth’s natural process/human activity[1]

b) Ethanoic acid is a weak acid and is the main constituent of vinegar.

(i) Write the molecular formula of ethanoic acid.

_______________________________ [1]

b) Ethanoic acid is a weak acid and is the main constituent of vinegar.

(i) Write the molecular formula of ethanoic acid.

CH 3 COOH/CH 3 CO 2 H [1]

(ii) Draw the full structural formula of ethanoic acid, showing all bonds. [2]

(ii) Draw the full structural formula of ethanoic acid, showing all bonds. [2] 1 Mistake [1], 2 Mistakes [2].

If – OH then [1]

c) Ethanoic acid behaves as a typical dilute acid. A student decided to investigate some of the reactions of ethanoic acid.

(i) Some copper carbonate was added to a solution of ethanoic acid with stirring. Describe the observations the student would make during this reaction.

_______________________________ _______________________________ _______________________________ [3]

c) Ethanoic acid behaves as a typical dilute acid. A student decided to investigate some of the reactions of ethanoic acid.

(i) Some copper carbonate was added to a solution of ethanoic acid with stirring. Describe the observations the student would make during this reaction.

Green [1] solid disappears [1], bubbles / fizzing / gas given off [1], blue solution formed [1], heat given off [1]. Max [3]

(ii) A strip of magnesium metal was added to a solution of ethanoic acid. State the name of the gas given off during this reaction and describe a test which could be carried out to confirm the presence of this gas.

Gas ____________________________ [1] Test ____________________________ _______________________________ [2]

A strip of magnesium metal was added to a solution of ethanoic acid. State the name of the gas given off during this reaction and describe a test which could be carried out to confirm the presence of this gas.

Gas Hydrogen [1] Test Apply a lighted splint [1], pop [1] [2]

(iii) Finally some sodium hydroxide solution was mixed with a solution of ethanoic acid. State the name and write the formula of the salt produced.

Name __________________________ [1] Formula ________________________ [1]

(iii) Finally some sodium hydroxide solution was mixed with a solution of ethanoic acid. State the name and write the formula of the salt produced.

Name Sodium ethanoate Formula CH 3 COONa [1] [1]

d) Esters are organic compounds which occur naturally in fruits. One such ester, ethyl ethanoate, can be produced by reacting ethanol with ethanoic acid.

(i) Write a balanced symbol equation for the formation of ethyl ethanoate.

_______________________________ [2]

d) Esters are organic compounds which occur naturally in fruits. One such ester, ethyl ethanoate, can be produced by reacting ethanol with ethanoic acid.

(i) Write a balanced symbol equation for the formation of ethyl ethanoate . [2] CH 3 COOH + C 2 H 5 OH → CH 3 COOC 2 H 5 + H 2 O

(ii) What conditions are required for the preparation of ethyl ethanoate in the laboratory?

_______________________________ _______________________________ _______________________________ [3]

(ii) What conditions are required for the preparation of ethyl ethanoate in the laboratory?

Add concentrated [1] sulphuric acid [1] Warm [1] [3]

(iii) Draw the structural formula of ethyl ethanoate, showing all bonds. [2]

(iii) Draw the structural formula of ethyl ethanoate, showing all bonds. [2] One bond missing = [1] Two bonds missing = [0]

(iv) State one use of ethyl ethanoate.

_______________________________ [1]

(iv) State one use of ethyl ethanoate .

Solvent/Flavouring [1]

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