INTERMEDIATE 2 UNIT 2PAST PAPER WRITTEN QUESTIONS 2001-2009
CARBON COMPOUNDS
2001
1. / A very hot flame is produced when ethyne gas (C2H2) burns in a plentiful supply of oxygen.(a) / Name the products formed in this reaction. / 1
(b) / Ethyne is the first member of an homologous series called alkynes.
Ethyne has the following structure.
All the members of the alkyne series have a triple carbon to carbon bond.
Complete the table below.
Position in series / Name / Molecular formula
1st / ethyne / C2H2
2nd / C3H4
3rd / Butyne
/ 2
(3)
2002
2. / Lavender flowers contain an oil.
(a) / Lavender oil is produced from the flowers by steam distillation. The flowers are put into a flask with a little water. Steam from a steam generator is blown through them to extract the oil. The mixture of lavender oil and steam distils over. It is condensed and collected.
The pieces of apparatus which are used to carry out this steam distillation are shown below.
Put a letter in each box to show the order in which the pieces of apparatus should be arranged to obtain the mixture.
/ 1
(continued)
(b) / The structural formulae for two of the compounds in lavender are shown below.
(i) / To show that lavender oil contains unsaturated compounds it can be tested by shaking a sample with bromine solution.
Bromine solution is corrosive. Apart from wearing safety goggles, give another safety precaution which should be taken when shaking the sample with bromine solution.
1
(ii) / Linalool is an alcohol. Circle the alcohol group in the linalool molecule shown above. / 1
(iii) / Linalyl ethanoate is made from an alcohol and ethanoic acid.
To which group of compounds does linalyl ethanoate belong? / 1
(iv) / Draw the full structural formula for ethanoic acid. / 1
(5)
2002
3. / Gases can be liquefied by increasing the pressure, but above a certain temperature it is not possible to do this. This temperature is known as the critical temperature. The critical temperatures of some alkanes are shown below.
(a) / Describe the trend in critical temperatures for the straight-chain alkanes.
1
(b) / Predict the critical temperature of the alkane
˚C / 1
(2)
2006
4. / Methylpropene and an alkane can be use to produce 2,2,4-trimethylpentane, a molecule added to petrol.(a)
(b) / (i)Give the systematic name for the alkane used to produce 2,2,4-trimethylpentane.
______
(ii) Name the type of chemical reaction shown above.
______
A similar reaction can be used to prepare 2,2-dimethylpentane.
Draw a structural formula for the alkene used to form this molecule.
/ 1
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(3)
2007
5. / Thiols are organic compounds containing sulphur. Some thiols are listed in the table.(a)
(b)
(c ) / Ethanthiol is added to natural gas to give it a smell.
Draw the full structural formula for ethanediol.
Suggest a name for thiol X.
Thiols undergo complete combustion.
thiols + oxygen → carbon dioxide + water + ______
Complete the word equation for this reaction. / 1
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(3)
2008
6. / Chlorofluorocarbons (CFCs) are a family of compounds which are highly effective as refrigerants and aerosol propellants. However, they are now known to damage the ozone layer.One example of a CFC molecule is shown.
(a) / What term is used to describe the shape of this molecule? / 1
(b) Scientists have developed compounds to replace CFCs. The table shows information about the ratio of atoms in CCl2F2 and compounds used to replace it.
(i)
(ii)
(iii) / Draw a possible structure for Replacement 2
Compared with, the replacement compounds contain less of which element?
From the table, what is the advantage of using the replacement molecules as refrigerants and aerosol propellants? / 1
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(4)
2008
7 / Infrared spectroscopy can be used to detect the bonds present in molecule.The same bond always absorbs infrared radiation at the same wavenumber, even in different molecules.
For example the C – H bond absorbs in the range 2800 – 3000 wavenumbers.
The infrared spectra of two different organic compounds are shown.
(a) / The absorption at wavenumber 1600 in the spectrum of butane is not present in the spectrum of propane.
Which bond could be responsible for this absorption/ / 1
(b) / The O-H bond absorbs in the ranger 3500 - 3700 wavenumbers.
Sketch the infrared spectrum you would predict for ethanol.
/ 1
(2)
2009
8. / The octane number of petrol is a measure of how efficiently it burns as a fuel. The higher the octane number, the more efficient the fuel.(a) / What is a fuel? / 1
(b) / The octane numbers for some hydrocarbons are shown.
(i)Predict the octane number for hexane.
(ii)State a relationship between the structure of the hydrocarbon and their efficiency as fuels. / 1
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(3)
REACTIONS OF CARBON COMPOUNDS
2001
1. / Hydroxy acids are compounds that contain both a hydroxyl group and a carboxylic acid group within the same molecule.
These compounds are able to form cyclic esters called lactones.
(a) / Draw the structural formula for the lactone formed when this hydroxyl acid reacts.
/ 1
(b) / Draw the structural formula for the hydroxyl acid from which this lactone was formed.
/ 1
(2)
2002
2. / Iodine can react with propene in the following way.
(a) / (i) / Name the homologous series to which propene belongs / 1
(ii) / Name the type of chemical reaction which takes place when iodine reacts with propene. / 1
(b) / Calculate the mass of iodine, in grams, that will react with 100g of propene.
g / 2
(c) / The mass of iodine that reacts with 100g of a substance is known as the iodine number.
Explain why oils are likely to have higher iodine numbers than fats.
1
(d) / Liquid oils can be converted into hardened fats using a solid catalyst.
The catalyst used is the transition metal, nickel. What type of catalyst is the nickel? / 1
6
2003
3. / (a) / Name the alkane shown below.
/ 1
(b) / Alkanes can be reacted with alkenes to produce longer chain alkanes.
Draw the structural formula of the alkane formed in the following reaction.
/ 1
(2)
2004
4. / Candle wax is a hydrocarbon.
Blue cobalt chloride paper and limewater can be used to detect products formed when candle wax is burned.
(a) / Complete and label the diagram to show the arrangement you would use.
/ 2
(b) / Name the product detected using the blue cobalt chloride paper. / 1
(c) / As the candle burns the funnel becomes coated with soot.
Why does this happen?
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(4)
2004
5. / Ethyl ethanoate can be made by reacting ethanoic acid and ethanol.
(a) / Name this type of chemical reaction. / 1
(b) / A method of making ethyl ethanoate from ethanol only, has been developed.
2C2H5OH CH3COOC2H5 + 2X
(i) / Name substance X. / 1
(ii) / This method was developed for use in countries where ethanol is made from a renewable source.
Name this source of ethanol. / 1
(3)
2005
6. / Propene can take part in addition reactions.
(a) / (i) / Draw the structural formula for propan-2-ol / 1
(ii) / Give another name for the addition reaction that produces propan-2-ol. / 1
(b) / Identify substance Y. / 1
(c) / Draw a section of the polymer formed from propene showing three monomer units linked together. / 1
(4)
2005
7. / The diagram shows how an ester with a “pear drops” smell can be made.
(a) / (i) / Name the ester formed. / 1
(ii) / Why can this reaction be described as a condensation reaction?
1
(b) / Polyesters are synthetic fibres.
Part of the structure of a polyester fibre is shown below.
(i) / Why are polyester fibres described as synthetic? / 1
(ii) / Circle an ester link in the polyester structure. / 1
(4)
2005
8. / Propane can be cracked to produce a mixture of smaller molecules.
(a) / Catalysts can be used to speed up a chemical reaction.
Give another advantage of using a catalyst.
1
(b) / Name the process used at step 2 to separate the product mixture. / 1
(c) / Complete the flowchart by naming the other product separated from the mixture. / 1
(3)
2005
9. / (a) / Draw the full structural formula for propanoic acid. / 1
(b) / The diagram below shows how an alkane can be prepared from an alkanoic acid.
The equation for the reaction is:
alkanoic acid alkane + carbon dioxide
Complete the table to show which alkanoic acid could be used to produce butane.
Alkanoic acid / Alkane
ethanoic acid / methane
propanoic acid / ethane
butane
/ 1
(2)
2006
10. / (a)(b) / Draw the full structural formula for ethanol.
The dehydration of ethanol to ethane was carried out using the following apparatus.
(i) Complete the word equation for the reaction
Ethanol Ethene + ______
(ii)As a safety precaution, the delivery tube was removed from the water before heating was stopped.
Why was this done?
(iii)Why is the aluminium oxide catalyst described as being heterogeneous?
(iv)What would the mass of aluminium oxide catalyst be after the reaction was complete? / 1
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(5)
2007
11. / When a hydrocarbon is burnt, carbon dioxide and water are produced. The following experiment can be used to investigate the products of combustion
(a)
(b) / Complete the diagram to show the apparatus which would be used to collect the water.
When the carbon dioxide produced in the reaction is passed through the pH indicator solution, the solution turns green to red.
What does this colour change suggest about carbon dioxide?
______/ 1
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(2)
2008
12. / Scientists have replaced oils in gloss paints with synthetic polyesters.This has improved the drying quality of the paint.
The first step in the production of the synthetic polyester is shown.
(a) / What does the term synthetic mean? / 1
(b) / Circle an ester link in the triglyceride. / 1
(c) / Name X / 1
(3)
2009
7. / The diagram shows how paraffin, C12H26 , can be cracked.(a) / Name the catalyst used in cracking. / 1
(b) / One of the reactions taking place when paraffin is cracked is
(i)Identify molecule X.
(ii)Describe what would be seen when X is added to bromine solution. / 1
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(3)
2009
8. / Alkynes are a homologous series of hydrocarbons which contain carbon to carbon triple bonds. Two members of this series are shown.(a) / Name the first member of this series. / 1
(b) / Alkynes can be prepared by reacting a dibromoalkane with potassium hydroxide solution.
(i)Draw a structural formula for the alkyne formed when the dibromoalkane shown reacts with potassium hydroxide solution.
(ii)Suggest a reason why the dibromoalkane shown below does not form an alkyne when it is added to potassium hydroxide solution.
/ 1
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(3)
2009
9. / The flow chart shows some of the stages in the manufacture of ethanoic acid.(a) / In the mashing process, some of the starch is broken down into glucose.
Using the flow chart, write the word equation for the reaction taking place in the mashing process. / 1
(b) / Name process X. / 1
(c ) / Draw the full structural formula for ethanoic acid / 1
(d) / Ethanoic acid can be reacted with methanol to form an ester, which is used as a solvent in nail varnish remover.
Name this ester / 1
(4)
MAN MADE POLYMERS/PLASTICS
2001
1. / Poly(ethenyl ethanoate) is an addition polymer. Part of its structure is shown below.
(a) / Draw the structural formula for the monomer used to make this polymer. / 1
(b) / Poly(ethenyl ethanoate) is used to make the polymer poly(ethanol).
poly(ethenyl ethanoate) + methanol →poly(ethanol) + methyl ethanoate
Methyl ethanoate is also formed in the reaction.
(i) / What property of poly(ethanol) makes it useful for laundry bags?
1
(ii) / Draw a structural formula for methyl ethanoate. / 1
(3)
2002
2. / Kevlar is a recently developed polymer.
(a) / State a useful property of Kevlar. / 1
(b) / The monomers used to make Kevlar have the following structural formulae.
Why are these molecules able to take part in condensation polymerisation?
1
(c) / Kevlar is an example of a polyamide.
Draw the structure of an amide link. / 1
(3)
2003
3. / Nylon is a polymer.
The monomers shown below are used to produce a nylon.
(a) / Draw a section of the polymer showing the three monomer units linked together.
/ 1
(b) / What feature of their structure makes these molecules suitable for use as monomers?
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(2)
2006
4. / Kevlar is a thermosetting polymer which can be used to make bullet-proof vests.(a)
(b) / The diagram below shows how the monomers used to make Kevlar link together.
(i)What type of polymerisation takes place?
______
(ii)Name the type of link formed.
______
(iii)Why is it important that the monomers have functional groups at each end of the molecule?
______
______
______
What property of Kevlar makes it suitable for use in bullet-proof vests?
______
______/ 1
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(4)
2007
5. / Polystyrene is made from the monomer styrene. The systematic name for stryrene is phenylethene.(a)
(b)
(c) / The monomer used to form polystyrene is shown.
Which part of the structure of styrene allows the polymer to form ?
Complete the digram to show how three styrene molecules join to form part of the polymer chain.
Give another name for polystyrene.
______/ 1
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(3)
2008
6. / Poly(ethenol) is one of the substances used to cover dishwater tablets.A section of the poly(ethanol) polymer is shown.
(a) / Name the functional group present in this polymer. / 1
(b) / Draw the structure of the repeating unit for this polymer. / 1
(c) / A dishwasher tablet, complete with its poly(ethanol) cover, can be added to a dishwasher.
What property of the poly(ethenol) makes it suitable asa cover for a dishwasher tablet? / 1
(3)
NATURAL PRODUCTS
2001
1. / Enzymes are biological catalysts. A chemistry class was investigating how the activity of an enzyme changed with pH.
They carried out experiments at different pH values and timed how long it took for the enzyme to break down starch. The more active the enzyme, the shorter the time taken to break down the starch.
Here are their results.
(a) / Name the type of chemical reaction taking place when starch is broken down. / 1
(b) / To which class of compounds do enzymes belong? / 1
(c) / What effect does increasing the pH from 5 to 6 have on the activity of the enzyme?
1
(d) / Some students suggested speeding up the rate of the reaction by heating the starch and enzyme mixtures in boiling water baths.
Why would this not speed up the reaction rate?
1
(5)
2003
2. / Yoghurt is made by fermenting fresh milk. Enzymes help to convert lactose in the milk to lactic acid.
(a) / What is an enzyme? / 1
(b) / The structural formula for lactic acid is shown below.
Circle the carboxyl group in the lactic acid molecule. / 1
(c) / Sugar can be added after fermentation has taken place to sweeten the yoghurt.
Suggest why the sugar is added after the fermentation stage and not before.
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(3)
2003
3. / The table below shows the saturated and unsaturated fatty acid content of a fat and an oil.
Source / Fat/oil / % Fatty acid in substance
Saturated / Unsaturated
animal / chicken fat / 68 / 32
marine / cod liver oil / 25 / 75
(a) / What do fats and oils provide in our diet? / 1
(b) / Name another source of fats and oils. / 1
(c) / Why do oils have a lower melting point than fats?
1
(d) / How can oils be converted into hardened fats?
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(4)
2004
4. / Jelly is made from a protein called gelatin.
(a) / Name the type of monomers which join together to form proteins. / 1
(b) / A section of the gelatin structure is shown below.
(i) / Circle a peptide link in this section of the gelatin structure. / 1
(ii) / Draw the structure of the monomer which makes this section of the gelatin structure. / 1
(c) / Papain, an enzyme found in pineapple juice, can hydrolyse gelatin.
When papain is heated to a high temperature it no longer hydrolyses the gelatin. Suggest why.
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(4)
2005
5. / Fats are broken down in the body by hydrolysis.
(a) / When one mole of fat is hydrolysed, how many moles of fatty acids are produced? / 1
(b) / Name the molecule with the structure shown.
/ 1
(c) / Lipase is an enzyme which can catalyse the hydrolysis of fats in milk.
Complete the diagram to show how the indicator colour would change after lipase was added to the test-tube.
/ 1
(3)
2006
6. / Carbohydrates are an essential part of our diet.(a)
(b)
(c) / Why are carbohydrates an important part of our diet?
Name the elements present in carbohydrates.
A student tested the carbohydrates glucose, sucrose and starch as shown.
Complete the table by identifying each carbohydrate.
/ 1
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(4)
2007
7. / The fermentation of glucose is catalysed by the enzyme zymase.
(a) / Balance the equation. / 1
(b) / A series of fermentation experiments was carried out at different temperatures and the volume of carbon dioxide was measured..
(i) Plot a line graph of these results, showing the temperature of the reaction against the volume of CO2 collected.
(ii) When the experiment was carried out at 70oC, no carbon dioxide was produced.
Suggest a reason for this.
______/ 1
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(3)
2007
8. / The silk that spiders spin into a web is made from a protein called fibroin. Two of the amino acids spiders used to make this protein are glycine and alanine.
When fibroin is formed, the glycine and alanine are joined by a peptide link. Part of the structure is shown below.
(a) / Circle a peptide link in the protein structure / 1
(b) / Complete the structure by adding a another molecule of glycine. / 1
(c) / Name the type of polymerisation that produces fibroin.
______/ 1
(3)
2008
9. / The enzyme phosphorylase catalyses the formation of starch from sugars.(a) / Name the monomer used to make a starch polymer / 1
(b) / Name the solution used to test for starch. / 1
(c) / A student investigated the effect of temperature on the rate of starch formation. The results are shown.
(i)Plot these results as a line graph.
(ii)At 32oC the relative rate was 0.0125s-1.
Use this rate to calculate the reaction time at 32oC.
______seconds / 1
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(4)
2008
10. /Use the article to answer the following questions.
(a) / Proteins can be denatured
Describe what happens to the protein when it is denatured. / 1
(b) / Other than heat, give a method that could be used to “cook” fish. / 1
(c) / Proteins can be denatured at low temperatures.
What does this suggest about the strength of the bonds keeping the protein twisted and folded? / 1
(d) / Draw a graph to show the relationship between cooking temperature and the cooking time for fish.
/ 1
(4)
2009
9. / The enzyme RuBisCo is one of the most abundant enzymes on Earth.It contains lysine at its active site.
(a) / Lysine contains two different types of functional groups.
Circle an amine group in the lysine molecule shown above. / 1
(b) / Name the family of compounds to which lysine belongs. / 1
(c ) / Complete the equation to show the structure of the other product formed when two molecules of lysine react.
/ 1
(3)
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