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E x a m in at io n a n s we1.1 Rings, polymers and analysis1 (a) Structure:

rs

(iii)

Br

Br2

HBr

(iv) Bromobenzene (b)Br H Br Step 2 Br

Empirical formula: CH (b) Concentrated nitric acid and concentrated sulfuric acid. (c) (i) NO2+ (ii) HNO3 + H2SO4 NO2+ + HSO4 + H2O (iii) NO2 ON HNO22

Step 1

H

Intermediate

(c) (i)

Cyclohexene H H H H Benzene H H H H H p orbitals H H overlap H H H H H H H p orbitals overlap to give a H bond above and below the H two carbon atoms H See diagram 00.00.00.00 H

H

H

2 (a) (i) I: Br2, II: NaOH (ii) Dye, colouring or indicator. (iii) Add phenylamine to sodium nitrite and hydrochloric acid below 10 C. Add this product to an alkaline solution of phenol. (b) H H H HC H C C H C H H C C H H C C C H C C C H

H

H

H

Theporbitalsoverlapaboveandbelowtheplane of the ring structure. Theelectronsaredelocalisedandspreadacross all six carbon atoms. Inbenzeneallthebondsarethesamelength between the lengths of the single and double bonds. henolismorereactivebecausetheringis P activated.Thelonepairfromtheoxygenonthering is delocalised into the ring so electrophiles are more attractedtotheringthaninbenzene. 3 (a) (i) FeBr3 or AlBr3 (ii) Halogen carrier.

(ii) nbenzenetheelectronsarespreadoverthe I whole ring structure, as they are delocalised. When cyclohexene is reacted with bromine the bromine is polarised by the double bond. However,whenbenzeneisreactedwith bromine, the bromine cannot be polarised by theringastheelectronsarespreadoverthe molecule. Electrophiles are less attracted to the benzene.Greaterenergyisneededtobreakthe cloudinbenzenethanincyclohexene. 4 (a) (i) D = Propanone (ii) E = Propanal (b) (i) eagent(s):2,4-dinitrophenylhydrazine. R Observation:orangeprecipitate. (ii) eagents:Tollensreagent.ObservationforD: R nochange.ObservationforE:Silvermirror formed.

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1

5 (a) CH3CHO + 2[H] CH3CH2OH (b) O C CH3 H H

8 (a)H H O H

H C H

H C H

H C H

H C H H H C H H H C H H OH OH H C H H C H H C O H H C H H

NaBH4 Step 1 CH3 HO H H

O C H

Butan-1-ol

IntermediateH H C H CH3 C H

Ethanal

Step 2

Butan-2-ol

CH3

C

H C C OH H H C H H

2-methylpropan-1-ol

H Organic product

(iii) An electron-pair donor (iv) henucleophileisattractedtothepositive T charge.Lonepairofelectronsformsadative bond. An electron pair from the double bond goestotheoxygenatom.The bond in the carbonyl bond breaks. (c) Hydrogendoesnothavealonepairofelectrons. 6 (a) OO Z-but-2-enal cis but-2-enal E-but-2-enal (trans)

2-methylpropan-2-ol

(b) (i) ddTollensreagent.Heatreactioninawater A bath.But-2-enalgivesasilverprecipitateor silvermirror. (ii) Aldehydes can be oxidised but ketones cannot. (c) (i) CH3CH=CHCH2OH (ii) Redox reaction/reduction or addition. (d) C4H6O + 5O2 4CO2 + 3H2O 7 (a) (i) eagent:Tollensreagent.Observation:silver R mirror formed. Organic product: butanoic acid. (ii) eagent:bromine.Observation:decolourises. R Typeofreaction:electrophilicaddition. (b) Recrystallise the product in order to purify the orange precipitate. Measure the melting points of the crystals. Compare known melting points with data tables.

(b) (i) Butan-1-ol can be oxidised to produce butanal andfurtheroxidisedtogivebutanoicacid.This occurs as primary alcohols can be oxidised. Butan-2-ol can be oxidised to produce butanone. No further oxidation occurs as ketones cannot be oxidised. 2-Methylpropan-2ol cannot be oxidised as it is a tertiary alcohol and is not oxidised. 2-Methylpropan-1-ol can be oxidised to produce 2-methylpropanal and further oxidised togive2-methylpropanoicacid. D: 2-methylpropan-1-ol. E: 2-methylpropanoic acid. (ii) (CH3)2CHCOOH + C2H5OH (CH3)2CHCOOC2H5 + H2O (c) H H H H OHO C H C H C H C H C ONa

9 (a) (i) Methyl butanoate. (ii) Heat/boil/warm/reflux with aqueous HCl or aqueous NaOH. (b) (i)HO

(ii)

HO or

HOCH2CH2 C H C

H

C2H5

2

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(iii)

O C H3C O CH2 CH2 C H C H CH2CH3

12 (a) Stage 1: React phenylamine with sodium nitrite and hydrochloricacidat10Corbelow.Thisformsa diazoniumsaltwhichisunstableandmustbekept below10C.Stage2:Reactthediazoniumsaltwith an alkaline solution of phenol below 10 C.NH2 N2Cl

10 (a) (i) Concentrated H2SO4. (ii) hisistopreventthelossofreactantsand T productsbyevaporation. (b) (i) HH H C H O C H O H H C C C C H H H H H

2 HCI NaNO2

NaCl 2 H2O (Diazonium salt)

N2

Cl

OH

NaOH

(c) 11 (a) (b) (c)

(ii) Butan-2-ol. Flavouringsorperfumes. A compound containing nitrogen where the nitrogen is attached to one carbon atom only. + C2H5NH2 + H+ C2H5NH3 (i) tageI:Sn,conc.HCl.StageII:NaNO2, HCl. S StageIII:Phenol,NaOH. (ii) Stage INO2 NH2

HO

N OH

N

NaCl H2O

(b) (i)

N N SO3Na

6[H]

2 H2O

SO3Na E110

CH3 Stage III N2Cl OH

CH3

(ii) 16 carbon atoms and 10 hydrogen atoms. (c) NaOH(aq) OH (d)

H2N Amine

SO3Na

CH3

NaOH SO3Na

CH3

N

N

OH NaCl H2O

Phenol

(iii) Dyes.

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3

13 (a) Diamino compound contains two amine groups 1,4 shows the position of the amine groups on the benzenering. (b) (i) Reduction/redox reaction. (ii) TinandconcentratedHCl.Heatunderreflux. (iii)O2N NO2 12[H]

(iii) Use a naturally occurring amino acid. (iv) higherdosewouldberequired.Theother A stereoisomermayhavesideeffects. 2 (a) (i) RCH(NH2)COOH (ii) H H HH H C H N H H C C C H H C H C O H O H

H2N

NH2 4H2O

(c) (i) heaminogroupacceptsH+ using its lone pair T or electrons on the nitrogen and forming a co-ordinate bond. (ii)ClH3NNH Cl 3

(b) (i) nionwhichhasbothapositiveandanegative A charge.Theoverallchargeiszero. (ii) A proton is transferred from the acidic COOH group to the basic NH2 group.H N H R C H C O H O H H H N

R C H C

O

O

14 (a)

CH3(CH2)6CH2 C H C

CH2

(CH2)6COOH

H

(b) (i) Oleic acid: C18H34O2. Ethanol: C2H6O. Ethyl oleate: C20H38O2 (ii) C18H34O2 + C2H6O C20H38O2 + H2O (c) Hydrolysis using hot aqueous HCl.

Heat with HCl (aq). Hydrolysis. Ammonia in ethanol. Leucine synthesised in the laboratory contains a mixture of two optical isomers. Leucine from meat (a natural source) contains only one of the isomers. 3 (a) For L: (c) (i) (ii) (d) (i) (ii)

1.2 Polymers and synthesis

1 (a) (i) Hydrochloric acid. Aqueous acid heated under reflux. (ii) Amino acids. H H (iii) OH

H C H C H O C H H C OH C O O O O C O H O C O O C H C OH H O

N H

C H

C O H

(or equivalent)

For M:H

(iv) A reaction with water which breaks down a compoundintosmallersub-units.Inthereaction abovethepeptidebondisbroken. (b) (i) For stereoisomerism in compound A, there must be a chiral centre, which is a carbon atom with four different groups attached to it. Stereoisomerism occurs when there is a differentspatialarrangementofthegroups.Two mirror images that are non-superimposable are observed. (ii) hemoleculecontainstwochiralcentresand T each chiral centre has two isomers.

(b)

4

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(c) tisacondensationreaction.Whenthereaction I occurs a small molecule such as water is lost. (d) Fibres/clothing. 4 (a) (i) H H H H H HC C H3C CH3 C H3C CH3 C C H3C CH3 C

I ncondensationpolymerisation,apolymersuchas PETisformedwhenmonomersinthiscase ethane-1,2-diolandbenzene-1,4-dicarboxylicacid join together and lose a small molecule for each bondthatforms.Inthecaseofthispolyester,a water molecule forms for each ester linkage that forms between OH and HOOC.Addition: Monomer ethene H n H Condensation H HO C H H C H OH HO O C O C OH C C H H H C H H C H H C n H H C H

(ii) CH2 (iii) HC H H C O N C

H

CH3

(b) (i) Name of functional group: peptide.

(ii) Condensation. (iii) Displayed formula of H:H N H H C H C O H N H2N O OH H N H C H O C O H O

H O C H

H C H CH3 O

O C

O C n H2O

(b) (i)H C H C H O

Skeletal formula of H:

C

O

(ii) Reagents: HCl (aq). Conditions: Heat and reflux (iii) CH3COOH (c)O C OH HO C O HO H C H H C H OH

(iv) No. of moles of glycine = 1.40/75.0 = 0.0187 moles. Expected no. of moles of dipeptide = 0.0187/2 = 9.33 103 mol. Expected mass = 9.33 103 132 = 1.232 g. % = (1.10/1.232) 100. Percentage yield 89.3% H H (v) OCl H

N H

C H

C OH

6 (a)

O C Cl (CH2)4C

O

H N H 1,6-diaminohexane (CH2)6N

H

5 (a) Inadditionpolymerisation,theC=Cdoublebondin an unsaturated molecule (monomer), such as ethene, breaks open and the monomer adds on to agrowingpolymerchain.Themonomersaddone at a time to form a long polymer such as poly(ethene), HDPE.

Cl Hexanedioyl dichlorideO C (CH2)4 O C N

H

(CH2)6

N H

HCI

H Repeat of unit polymer

Other product

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5

(b) (i)HO

O C

O C OH

(iv)H

H C

Cl

O O

H O C H Cl

CH3H C H H

C

H N H N H H

O

C