2009 Chemistry TrialHSC Independent org

8/4/2019 2009 Chemistry TrialHSC Independent org

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NSW INDEPENDENT TRIAL EXAMS - 2009CHEMISTRY TRIAL HSC EXAMINATION

MARKING GUIDELINES

Section I - Part B16(a)Criteria MarksEthylene is obtained by the catalytic cracking of longer chained fractions of petroleum. 2These hydrocarbons are heated strongly in the absence of air but in the presence of acatalyst. The carbon chains are broken into shorter chain lengths. Continued crackingultimately results in the formation of ethylene.16(b)Criteria Marks

CH2= CH2 + H2O CH3CH2OH 2The catalyst used is dilute sulfuric acid.16(c)Criteria MarksEthanol can be dehydrated to form ethylene. 3

CH3CH20H CH2 = CH2 + H2OThis reaction can be performed in the presence of a strong dehydrating agent such asconcentrated sulfuric acid.Ethanol can be obtained by the fermentation of sugars from renewable sources such assugar cane.

C6H 1206 2 CH 3CH20H + 2 C02The use of non-renewable petroleum resources can be reduced by obtaining ethylene viathe dehydration of ethanol formed by fermentation using renewable resources of sugars.17

5Criteria MarksAlkenes contain a reactive double bond in their carbon chain and so readily react withbromine in aqueous solution. The double bond opens up allowing bromine atoms tobond with the carbon atoms in an addition reaction.

Alkanes have only single bonds between carbon atoms. Hence, in the absence ofUVlight, bromine in aqueous solution does not react with alkanes.Bromine water is a yellow/brown colour due to the presence of the Br2 molecules. Whenthe Br2 reacts with alkenes, the bromine water loses its colour. TIns allows the fact that areaction has occurred to be easily identified.In the presence of alkanes, bromine water retains its yellow/brown colour as there is noreaction.Bromine water is therefore most suitable for the purpose of distinguishing betweenalkanes and alkenes as it readily undergoes an easily identified reaction with alkenes butdoes not react with alkanes.

NSW Independent Trial Exams 2009 - Chemistry Trial HSC Examination: Marking Criteria - Page 1


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18(a)Criteria MarksAtoms of zinc are ionised and accelerated to very high speeds in a particle accelerator 2before smashing into a lead target. If the zinc nuclei have sufficient energy to overcomerepulsive forces, they combine with lead nuclei forming a superheavy element such as112.

18(h)Criteria MarksTIlls type of research increases our understanding of the structure of the atomic nucleus 2and may produce new isotopes for use in areas such as industry and medicine.

19Criteria MarkThe chemical reactions that take place in a battery involve electron transfer between 3oxidant and reductant species. These reactions can be considered as separate oxidation(electron loss) and reduction (electron gain) reactions. Electrons from the reductant aretransferred to the oxidant during the reactions.In the construction of a battery, these two processes are physically separated so that theelectrons must move through an external circuit for the transfer to take place, allowingusable electrical energy to be generated. Inthe battery, the oxidant and reductant areseparated by a barrier that allows ions to move through it to complete the electricalcircuit and thus keep the two sides of the battery electrically neutral. The reductantforms the anode or negative terminal of the battery, while the oxidant forms the cathodeor positive terminal.

20(a)Criteria Marks

CO2(g) + 20H- -7 CO/- + H20 (or molecular form with 2NaOH) 2Ca2+ + cot -7 CaC03(s)

20(b)Criteria MarksMole mass ofCaC03 ::::40 + 12 + 48 = 100 g :.1000 kg = 10,000 moles 1Moles of CO2 needed = 10,000 moles:. Volume of CO2 needed = 10,000 x 24.79 = 247,900 LVolume of air to pass through "tree" = 247,900 / 0.00038 = 6.52 x 108 L 120(c)Criteria Marks1000 kg CaC03= 10,000 moles 1:.180 kJmarl x 10,000 moles = 1.8 x 106 kJ energy required1.8 x 106 kJ 11 000 kJ marl = 1.8 x 103 mol natural gas 1:. V = 1.8 X 103 mol X 24.79 L mol" = 4.46 x 104 L natural gas needed

21(a)Criteria MarksInthe reaction magnesium atoms are oxidised to form magnesium ions, showing that it 1is an oxidation-reduction reaction.Carbon atoms are reduced in the reaction (from +2 to 0). 1



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21(b)Criteria MarksThe monomeric tetrafluoroethylene is a low boiling substance (non-polar and low 1molecular mass) and chemically reactive owing to its double C=C bond.The polymer is a plastic which is stable and unreactive, as it has no multiple bonds, 1making it much more suitable for packing into a flare canister.22(a)Criteria Marks

Start Point (mL) End Point (mL) Vol H2S04 (mL) 10.0 18.6 18.618.6 37.3 18.712.8 31.5 18.7

Mean Volume: 18.722(b)Criteria MarksMoles NaOH ;;::: x moles H2SO4 or CbVb ;;::: 2 x c. 125 x 0.220 = 2 x 18.7 x c, and C. = 0.147 mol Lo tConcentration of H2S04 =0.147 mol r. ' 122(c)Criteria MarksInitial Moles H2SO4 = 0.5 x 0.25 = 0.125 mol 1Moles used to dissolve Mg = = 0.125 - moles remaining = 0.125 - 0.0735 = 0.0515 molMoles ofMg = moles H2S04 ;;:::0.0515mol Mass ofMg= 0.0515 x24.31 = 1.251965 g.'. Percentage of Mg by mass = 1.251965 x 100/2.12 = 59.05% (59.1% to 3 sf.) 122(d)

I Criteria MarksA 25.0 mL pipette is used. 122(e)Criteria MarksA measured mass of flare mixture is reacted with sulfuric acid under an inverted 2measuring cylinder, initially filled with water. After equalising water levels the volumeof hydrogen gas collected is measured and converted to moles, using the molar volumeof a gas under collection conditions. As one mole of Mg produces one mole ofhydrogen, the mass of magnesium can be determined.23(a)Criteria MarksCH3CH200CH (in expanded form showing all bonds). 123(b)Criteria Marks Small quantities (approximately equimolar) of ethanol and formic acid are mixed 2together in a boiling flask A little concentrated sulfuric acid is added. The flask is connected vertically to a condenser. The mixture is boiled under reflux.



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23(c)I Marksriteria

The isomeric compound is propanoic acid. (formula C3H602).Propanoic acid will change the colour of an acid-base indicator, such as litmus. Ethylformate has no acid-base properties. (or any other weak acid property such aseffervescence of CO2 with a carbonate)

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24(a) I MarksriteriaPhosphorus is present as phosphate ion, and iron (III) ion forms a precipitate of ironflll)phosphate. Fe3+ + pol -7 FeP04(s)'It is important to remove the phosphate ion from the effluent to minimise fertilisingaction, which would promote growth of aquatic plants and eutrophication.

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24(b)I Marksriteria

Anyone of chlorine, ozone or UV irradiation.The purpose is to destroy bacteria by strong oxidation (or UV exposure) to ensure noharmful pathogenic bacteria are present in the effluent.

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24(c)Criteria I MarksAdd excess dilute silver nitrate solution to a 100 mL sample of the effluent. Separate thesilver chloride precipitate by filtration, dry and weigh the solid.Ag+ + cr -7 AgCI (5)The mass and concentration of chloride ion can be calculated from the formula AgCl.

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1125(a), (b)Criteria Marks

Na +Concentration (mg L- )olution Absorbance at 589 nm(%) 2Standard 10 16Standard 20 34Standard 6 30Standard 60 98

2.5 43.2 532.5 54

Downriver sample 2 26.5 43(a)

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25 (c)Criteria MarksThese downriver sodium concentrations are within safe limits for freshwater organisms. 2During low rainfall periods the river flow will decrease, reducing the dilution effect. As aresult the downriver sodium concentrations will increase, possibly above the maximumlevel.

26(a)Criteria Marks

2Q::Q :0: The oxygen free radical is much lessoxygen stable than the oxygen moleculemolecule

26(b)Criteria MarksAn oxygen free radical combines with an oxygen molecule by means of a coordinate 2covalent bond. .. :g=...--Coordinate

Q::Q Bond

Section IIQuestion 27 - Industrial ChemistryQ 27(a)Criteria MarksSodium hydroxide is produced by the electrolysis of brine, a concentrated solution of 7sodium chloride in water. The sodium chloride is obtained by evaporation of seawater.In the modern membrane electrolytic cell, the brine is electrolysed using a titanium anodeand steel mesh cathode, supporting a membrane which separates the electrolyte into anodeand cathode compartments. The membrane allows sodium ions to pass through to thecathode, where water is reduced to hydrogen gas and hydroxide ions.

H20 + e- -7 12H2(g) + OR"The solution of sodium hydroxide is collected as it passes through the steel mesh cathodeand is then concentrated or obtained as the solid by evaporation. The anode reactionproduces chlorine by oxidation of chloride ions.

cr -7 ~Ch(g) + e'Sodium hydroxide is a white waxy solid which is extremely soluble in water. It is a verystrong base, and is the most widely used alkali in industry. Domestically it is used in drainand oven cleaners, for its ability to dissolve fatty deposits by the saponification reaction.Saponification is also the largest industrial use. It is used in the process of soap-making,where sodium hydroxide is used to convert fats and oils to soap and glycerol. A soap is amixture of the sodium salts offatty acids.Q 27(b)(i)Criteria MarksFor the reaction 2S02(g) + 02(g) -7 2S03(g) 2K, =[soi.;. ([S02f [02]) = 6262 .;. (2232 x 114) = 0.069



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Q 27(b)(ii)Criteria Marks

Property Total pressure Kp Yield OfS03 2Graph A C D(A,B,C,orD)

Q 27(b)(iii)Criteria MarksAt 25C the reaction would be extremely slow and it would take millions of years to reach 1equilibrium.Q 27(c)(i)Criteria MarksThree endothermic reactions are: 3

1. Decomposition of calcium carbonate: CaC03(s} -7 CaOes) + CO2(g)2. Ammonia recovery: Ca(OH)z + 2NH4CI -7 2NH3(g} + CaCh + 2H2O3. Production of sodium carbonate 2NaHC03(s } -7 Na2C03(Sl +C02f~l + H2O(!!:)Q 27(c)(ii)Criteria MarksThe most suitable fuel is natural gas which is easily transported by pipeline, has a high 2heat of combustion and bums cleanly, producing less carbon dioxide than other fossilfuels such as coal.Q 27(d)Criteria MarksSoap is a mixture of sodium salts of long chain fatty (carboxylic) acids. Each anionic 2molecule consist of a long non-polar alkyl chain which is hydrophobic and a highly polarand negatively charged carboxyl group which is strongly hydrophilic.

/V'-..~~OO-Mixed with water soap molecules form clusters called micelles forming an emulsion. 2Each micelle has a non-polar interior comprising alkyl groups and a surface layer of polarhydroxyl groups which form hydrogen bonds with water molecules. Grease and other non-polar molecules and are dissolved into the non-polar interior of the micelles, hence thecleansing effect of soap.Q 27(e)Criteria MarksA galvanic cell produces energy while an electrolytic cell consumes energy. In a galvanic 2cell an exothermic chemical reaction occurs to create a voltage and deliver current andenergy to an external circuit. e.g. electrodes of copper and magnesium immersed in apotassium nitrate solution. The magnesium anode is oxidised to magnesium ions whilewater is reduced to hydrogen at the copper cathode.An electrolytic cell can be made of stainless steel electrodes in a sodium chloride solution. 2An external voltage source drives current through the celL Water is reduced at the cathodeand the chloride ion is oxidised to chlorine at the anode.Question 28 - Shipwrecks, Corrosion and ConservationQ 28(a)Criteria MarksSteel-hulled ships operate in a strongly oxidising environment in which seawater provides 7a highly conducting electrolyte for electrochemical corrosion. Oxygen in the atmosphere,and dissolved in the surface layers of the ocean, is the principal oxidising agent, and allmetals are reducing agents. Iron, the most widely used metal is a strong reductant in thissituation, initially undergoing oxidation to iron(II) ions.

Fe(s) -7 Fe2+ + 2e-Question 28(a) continues on the next pageNSW Independent Trial Exams 2009 - Chemistry Trial HSC Examination: Marking Criteria - Page 6


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Question 28(a) continuedThe primary reduction reaction, which occurs on a suitable cathodic surface, is of oxygento hydroxide ion. Y2O2 + H20 + Ze' -7 20H"

The ultimate product is hydrated iron (III) oxide, or rust.Measures taken to combat corrosion include:1) Preventing contact of the seawater with the steel using impervious coatings such as

grease, paint or a passivating metal.2) Cathodic protection by embedding slabs of a more reactive metal which becomes a

sacrificial anode. In this situation the steel becomes a cathode and oxidation of iron isprevented. Using an inert metal such as titanium, an external voltage can be appliedfrom the ship's generators to make the steel hull a cathode in the cell so created.

3) Use of passivating metals, such as aluminium alloys, in place of steel for fittings andsuperstructure can also reduce the problem of corrosion.

4) Taking care to prevent contact of seawater with less active metals or alloys, such ascopper and bronze, which act as cathodes and accelerate the electrochemical corrosionof steel.

Q 28(b)(i)Criteria MarksTogether with salt spray the copper plate and galvanised bracket create an electrochemical 3cell in which the bracket is the anode. Corrosion of the bracket is accelerated due tocontact with the copper, with both zinc and iron being oxidised to 2+ ions, while oxygen isreduced at the copper cathode. Iron(II) ions then react with oxygen to form a deposit ofrust.Q 28(b)(ii)Criteria MarksIf sufficiently strong for the purpose a plastic bracket could be used, such as high density 2PVC, which is unreactive. Otherwise a passivating metal such as stainless steel or titaniumcould be used. These metals develop a tough and impervious oxide layer, whichminimises or prevents corrosion under these conditions.Q 28(c)(i)

Voltage source 2Criteria Marks

Stainless steelanodeHorseshoeArtefact_---t-~Cathode

Q 28(c)(ii)Criteria MarksAnode: 20H"-7 Yz02(g) + H20 +2e- or H20 -7 Y202(g) + 2ff' +2e- 2Cathode: e.g., F~03(s) + 3H20 + 6e- -7 2Fecs) + 60H' or Fe3++ 3e" -7 Fe(s)



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Question 29(a) continued Glucose-6-phosphate is then converted to glucose-l-phosphate by phosphoglucomutase Glycogen formation is endergonic which means it requires the input of energy. The energy for glucose synthesis comes from UTP which reacts with Glucose-l-phosphate to form

UDP-glucose. This reaction is catalysed by UDP-glucose pyrophosphorylase. Glycogenin initiates the synthesis of glycogen from the UDP-glucose monomers and the glycogen

synthase enzyme then adds UDP-glucose monomers to the glycogen chain. A branching enzyme forms branches off the glycogen chain. The bonds joining the glucose monomers are either 1,4 glycosidic (long chains) or 1,6 glycosidic

bonds (branches).

CH20HIHC-o,OHI H "IC,-OH H ~CI" I, IHO C-C HI IH OH ".1.4-9lycosidlclin~ages Glycogen is stored primarily in the liver and skeletal muscle. Glycogens function is to store

glucose or energy in a reserve that is able to be rapidly mobilised when required. Glycogen is a much larger molecule than fat which is another form of energy storage;

however its highly branched structure allows it to be rapidly broken down when required. Liver glycogen is responsible for maintaining blood glucose and muscle glycogen is utilised

during exercise.Q29(b)Criteria MarksProvides a comprehensive description of the relationship between the chemical 5features of a protein and its shape.Uses a relevant example to illustrate answer,Provides a description of the relationship between the chemical features of a 3-4protein and its shape.Uses a relevant example to illustrate answer.Provides some information about the relationship between the chemical features 1-2of a protein and its shape.Answer may include:

An amino acid contains a carboxyl end, an amine end, and an organic part known as an Rgroup.

The peptide bond is between the amine group of one amino acid and the carboxyl group ofanother.

A chain of amino acids linked by peptide bonds is a protein. When a protein is formed, certain interactions can influence the shape of the protein molecule. The R groups can form bonds with other amino acid R groups in the protein. Ionic bonds can form between oppositely charged side groups. R groups with 0 or N atoms can for hydrogen bonds to other R groups. Hydrogen bonds can

also form between C=;Q and N-H groups in the protein backbone. Dispersion forces can cause the formation of spiral helices, which exclude water. Disulfide bonds can form between two cysteine residues forming a strong covalent bond. All these factors cause the protein to bend and fold to form a unique shape.V2mark per point



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Q29(c)Criteria MarksProvides an accurate outline of the ATP production involved in sprinting. 3Provides some relevant information about the ATP production involved in 1-2sprinting.Answer may include:

When sprinting, muscles quickly use ATP. Heavy breathing indicates a need for oxygen for oxidative decarboxylation and oxidativephosphorylation. As the creatine phosphate supply last for approximately 5 seconds when sprinting and it takes

much longer for the oxygen breathed in to reach the muscle cells and replace the ATP thoughaerobic respiration, the sprinting muscles must use a non-oxygen (anaerobic) ATP productionmethod.

The method used is anaerobic glycolysis, which converts pyruvate to lactic acid, which istransported out of the cell in the blood stream. This allows for the regeneration of NADHwithout using oxygen.

The muscles can thus continue to convert one glucose to two pyruvate and release two ATP. As the lactic acid concentration increases in the blood, raising the pH, this process cannot

continue.Y z mark per point

Q29(d)Criteria MarksProvides an accurate outline of the role of oxygen in respiration. 3Provides some relevant information about the role of oxygen in respiration. 1-2Answer may include:

In the metabolism of glucose, glycolysis is the fIrst step. This is where the glucose isconverted to pyruvate. The pyruvate is then able to go down one of two separate paths.

If the oxygen supply is insufficient the pyruvate is fermented to lactic acid. This has a netproduction of2 ATP, and enables the NADH to be regenerated for reuse.

If there is oxygen present then the pyruvate will form acetyl-CoA and enter the TCA andeventually the electron transport chain.

This process produces much more ATP (approximately 36 more than glycolysis alone). With oxygen as the terminal electron acceptor, NADH and FADH2 are able to be oxidised and

thus regenerated.Y z mark per point



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Q29(e)Criteria MarksProvides a comprehensive description of the process of muscle contraction 5Provides a description of the process of muscle contraction 3-4Provides some information about the process of muscle contraction 1-2Answer may include:

Nerve cells stimulate the release of calcium ions. An electrical impulse is transmitted from nerves to the cell membrane of the muscle fibre. The impulse carried throughout the muscle cell causes the release of calcium ions as the

impulse passes. The calcium ion concentration increases by ten times and the calcium binds with troponin

causing a conformation change in tropomyosin which is released from the myosin binding siteon the actin filament This allows the myson to bind the actin.

The myosin hydrolyses ATP to .ADP and Pi. The ATP energy is released as mechanical energy where the actin filaments are pulled past the

myosin filaments. The actin and myosin filaments slide past each other and overlap more. The bonds between actin and myosin are temporary and are released when the calcium ion

concentration decreases, causing the muscle to relax. During the contraction the myosin and actin filaments do not change length. The myosin is attached to the Z disk via titin and when sliding over the actin causing

shortening of the sarcomere.lh mark per pointQ29(f)Criteria MarksProvides appropriate equations summarising the reduction/oxidation process in 2ATP regeneration.Refers to both electron carriers.Provides appropriate equations summarising the reduction/oxidation process in 1ATP regeneration.Refers to one electron carrier.Answer may include:



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Question 30 - Chemistry ofArtQu 30(a)Criteria MarksBohr proposed a model of the hydrogen atom with the electron occupying one of a limited set 7of circular orbits centred on the nucleus. Each available orbit has its own radius and energyvalue, with higher energy orbits being further from the nucleus. To move to a higher orbit theelectron has to absorb energy. When an electron drops to a lower orbit it emits energy as aquantum oflight. The Bohr model accounted for the main emission (and absorption) lines inthe hydrogen spectrum, and was the first to apply quantum ideas to atomic structure. However,it did not explain why orbits were restricted and was unable to account for the spectra of multi-electron atoms, or the more detailed structure of the hydrogen spectrum. Worse, the Bohr atomcould not exist as an orbiting electron must continually radiate energy and the atom wouldcollapse.More detailed spectral studies and ionisation measurements have led to a more elaborate wavemechanical model for the atom with each principal quantum (or energy) level being dividedinto sets of sublevels. Bohr's circular orbits have been replaced by three-dimensional regionscalled orbitals which are probability distributions for the location of the electron. The Pauliexclusion principle limits the number of electrons at each level, sublevel and orbital by statingthat no two electrons can have exactly the same state. Together with Hund's Rule thatelectrons occupy the lowest available energy levels this provides a model for all atoms of thePeriodic Table. Each block in the table corresponds to the completion of a sublevel. Eachperiod commences with a's' sublevel; Group 1& 2 block to the's' sublevels, Groups 3-8 tothe 'p' sublevels and the transition series to the 'd' sublevels. The rare earths and actinides forthe remaining blocks and correspond to the filling of 'f sublevels.Qu 30(b)(i)Criteria MarksThe unknown pigment will appear red-yellow in reflected light. 2Qu 30(b)(ii)Criteria MarksTitanium oxide shows high (100%) reflectance across the entire visible spectrum, providing 2the opacity needed of a paint pigment.Zinc oxide has high reflectance which extends into the near ultraviolet A region and reducesthe exposure of skin cells to damaging UV radiation from the sun.Qu 30(b)(iii)Criteria MarksOf these four pigments only zinc oxide shows reflectance extending into the UVA region and 1then only to a wavelength of around 360 nm, Zinc oxide provides the best, but incomplete,protection.Qu 30(c)Criteria MarksMicrospectral analysis (MSA) is a very sensitive and reliable method for identifying the origin 5of paint samples. It is able to detect the presence of elements at extremely low concentrations,and only requires a very small sample for analysis.MSA involves the vaporisation and atomisation of a small sample of material using an intenseultraviolet laser. The atoms are produced in an excited state and emit their characteristicemission spectrum.By comparing the spectrum produced to the spectra of known elements, the elements presentin the sample can be identified. Key lines in the spectrum produced can be used to identify theelements and their relative concentrations in the sample.Motor vehicle paints use a mixture of metal oxides as pigments and each paint batch has aunique combination of oxides, even for pigments of the same colour. Thus MSA can not onlyidentify the metals present but also the batch of paint used on the vehicle.



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Q 31(b)(i)Criteria MarksThe molecular formula for maltose, C12H22011[ or CdH20)1 d fits the general formula for a 1carbohydrate CxCH2O)v'Q 31{b)(ii)

OH HOH

OH ~ hydroxyl group

Maltose is a reducing sugar as it has a hydroxyl group (-OH) attached to the carbonyl atom inone of the ring structures.

2CriteriaMarks

oCH20Ho H ~ carbonyl carbon atom

H

Q 3 I(b)(iii)Criteria MarksSugars are made of one, two or three monosaccharide units joined together. Starch is made of 21000's of monosaccharide units joined together. Sugars made of more than onemonosaccharide unit, and starch can be hydrolysed to form monosaccharides.Q 3 I (c)(i)Criteria MarksAll amino acids contain an amine functional group (-NH2) and a carboxylic acid functional 1group (-COOH) in their molecules and have the following general structure

HIH N-C-COOH2 I

Rwhere R represents a hydrogen atom or a carbon containing side chain. Different amino acidshave a different R group.Q 3 I(c)(ii)Criteria MarksElectrophoresis is able to identify amino acids by using an applied electric field to separate 4them according to differences in their molecular mass and charge. A sample of the mixture tobe analysed is spotted on a piece of porous paper or gel alongside samples of separate pureamino acids for comparison. The paper or gel is soaked in an electrolytic solution containing asuitable buffer. When a voltage is applied across the paper or gel, positive ions will migrate inone direction; negative ions migrate in the opposite direction while neutral ions remainstationary. The speed of migration depends on the molecular mass - smaller less massivemolecules move faster.The charge on the amino acids depends on its isoelectric point and the pH of the electrolyticbuffer. At the isoelectric point, the amino acids exist as neutral ions. They will be negativelycharged at pH's well above this isoelectric point and positively charged at pH's well below.Electrophoresis is a very effective and reliable method for identifying the composition of amixture of amino acids. Each amino acid has a unique combination of molecular mass andisoelectric point. By repeating the analysis at different pH's all amino acids can be separated.The components of the mixture of amino acids can be identified by comparison with the pureamino acid samples run along side the sample being analysed. Each amino acid will move at aunique speed, allowing each component to be separated and analysed.



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Q 31(d)(i)Criteria MarksAn alkanol will react with sodium metal to produce hydrogen gas. 2e.g. C2HjOH (I) + Na (s) ... C2HjONa + 12H z (g)A hydrocarbon does not react with sodium metal.Q 31(d)(ii)Criteria MarksWhen heated in air, an organic compound will react with oxygen to produce carbon 2dioxide gas.e.g, CjH12 (I) + 8 O2 (g) .. 5 COZ(g) + 6H20 (I)An inorganic compound will not produce carbon dioxide gas when heated in air.Q 31(e)Criteria MarksDNA carries the genetic code that determines all of the inherited characteristics of a living 4organism. Because all humans have a large number of characteristics in common, over99% of a person's DNA will be identical to that of another person.Each DNA molecule contains thousands of genes, each gene separated from the next by a"non-coding" sequence of bases called introns. These introns vary significantly from oneperson to the next making each person's DNA unique.DNA analysis allows the comparison of DNA from different samples to establish whetherthey came from the same person or from different people. The huge number of possibleintron combinations means that the chances of unrelated people having matching DNA isone in many billion. Matches of DNA can then be considered a very reliable method foridentifying individuals. DNA profiles can be produced from very small samples from thebody. The reliability of the results will be very dependant on the procedures in place forpreventing contamination of the samples being tested. Forensic scientists take great care toensure that samples are not contaminated when collected or when being tested.



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NSW INDEPENDENT TRIAL EXAMS - 2009CHEMISTRY HSC TRIAL EXAMINATION

MAPPING GRIDQuestion Marks Content Target performancebands

1 1 9.2.4 3-42 1 9.2.5 3-43 1 9.2.3 4-54 I 9.2.1,9.9.2 2-35 1 9.2.3 2-36 1 9.3.2,9.3.3 3-47 1 9.3.4 4-58 1 9.3.3 3-49 1 9.3.4 3-510 1 9.3.4 3-411 1 9.3.2 2-312 1 9.4.4 3-413 1 9.4.2 3-514 1 9.4.3 4-515 1 9.4.4 3-416(a) 2 9.2.1 3-416(b) 2 9.2.3 2-416(c) 3 9.2.2,9.2.3 2-417 5 9.2.1 3-618 4 9.2.5 3-519 3 9.2.4 2-520(a) 2 9.3.2,9.4.3 2-420(b) 2 9.3.2 3-420(e) 2 9.3.2,9.2.3 3-421(a) 2 9.2.4 3-521(b) 2 9.2.1 4-522(a) I 9.3.4 2-322(b) 2 9.3.4 3-422(e) 2 9.3.4 4-522(d) 1 9.3.4 1-222(e) 2 9.1,9.3.2 5-623(a) 1 9.3.5 3-423(b) 2 9.3.5 2-423(c) 2 9.1,9.3.5 3-524(a) 2 9.4.2,9.4.5 4-524(b) 2 9.4.5 3-524(c) 3 9.4.2,9.4.5 4-625(a) 3 9.1,9.4.3 3-525(b) 2 9.1,9.4.3 3-525(e) 2 9.4.5 4-526(a) 2 9.4.4 3-426(b) 2 9.4.4 3-527 25 9.5 2-628 25 9.6 2-629 25 9.7 2-630 25 9.8 2-631 25 9.9 2-6


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2009 Chemistry TrialHSC Independent org