Physical Sciences Grade 12 Paper 2 NSC November 2018 Memo

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE NASIONALE SENIOR SERTIFIKAAT GRADE/GRAAD 12 PHYSICAL SCIENCES: CHEMISTRY (P2) FISIESE WETENSKAPPE: CHEMIE (V2) NOVEMBER 2018 MARKING GUIDELINE/NASIENRIGLYN MARKS/PUNTE: 150 These marking guidelines consist of 18 pages. Hierdie nasienriglyne bestaan uit 18 bladsye. Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 2 DBE/November 2018 NSC/NSS – NSC/NSS – Marking Guidelines/Nasienriglyne QUESTION 1/VRAAG 1 1.1 C  (2) 1.2 C  (2) 1.3 C  (2) 1.4 A  (2) 1.5 D  (2) 1.6 B  (2) 1.7 B  (2) 1.8 D  (2) 1.9 D  (2) 1.10 B  (2) [20] Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 3 DBE/November 2018 NSC/NSS – NSC/NSS – Marking Guidelines/Nasienriglyne QUESTION 2/VRAAG 2 2.1 ANY ONE/ENIGE EEN: • (Alcohol/ethanol) is flammable/catches fire easily.  (Alkohol/etanol) is vlambaar/slaan maklik aan die brand. • To heat it evenly./Om dit eweredig te verhit. • Water bath is used for low heat/low temperature./Waterbad word gebruik vir lae hitte/lae temperatuur. • Alcohol/ethanol will evaporate too quickly./(Alkohol/etanol) sal te vinnig verdamp. Accept/Aanvaar: (Alcohol/ethanol) is volatile./(Alkohol/etanol) is vlugtig. (1) 2.2 2.2.1 Esterification/condensation  Verestering/esterifikasie/kondensasie (1) 2.2.2 H 2 SO 4  (1) 2.2.3 Esters  (1) 2.3 M(ester ) 144 Marking guidelines/Nasienriglyne = =2 • If only answer given, award 2 marks on final M(C 4H8 O) 72  answer./Indien slegs antwoord gegee, ken 2 ∴ 2 x C 4 H 8 O = C 8 H 16 O 2  punte toe vir finale antwoord. • If 72 g·mol-1 calculated without substituting, no mark is awarded./Indien 72 g·mol-1 bereken is sonder om te vervang word geen punt toegeken nie. (2) 2.4 Ethyl  hexanoate  Etielheksanoaat Note/Aantekening Accept any other ethyl ESTER from QUESTION 2.3. Aanvaar enige ander etiel ESTER vanaf VRAAG 2.3. (2) Copyright reserved/Kopiereg voorbehou Please turn the page/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 4 DBE/November 2018 NSC/NSS – NSC/NSS – Marking Guidelines/Nasienriglyne 2.5 POSITIVE MARKING FROM QUESTION 2.4. POSITIEWE NASIEN VANAF VRAAG 2.4. H H H H H O  H C C C C C C O H  H H H H H Marking criteria/Nasienriglyne • Whole structure correct/Hele struktuur korrek: 2 2 • Only functional group correct/Slegs funksionele groep korrek: Max/Maks.: 1 2 • Accept/Aanvaar -OH as condensed/gekondenseerd. IF/INDIEN • More than one functional group/wrong functional group/Meer as een funksionele groep/foutiewe funksionele groep: 0 2 • If condensed structural formulae used/Indien gekondenseerde struktuur-formules gebruik: Max/Maks.: 1 2 (2) [10] QUESTION 3/VRAAG 3 3.1 Marking guidelines/Nasienriglyne If any one of the underlined key phrases in the correct context is omitted, deduct 1 mark./Indien enige van die onderstreepte frases in die korrekte konteks uitgelaat is, trek 1 punt af. The temperature at which the vapour pressure of a substance equals atmospheric/external pressure. Die temperatuur waar die dampdruk van 'n stof gelyk is aan atmosferiese/ eksterne druk. (2) 3.2 3.2.1 Carboxyl (group)/karboksiel(groep)  Accept/Aanvaar Carboxylic/Karboksiel (1) 3.2.2 Propanoic acid/propanoësuur  (1) Copyright reserved/Kopiereg voorbehou Please turn the page/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 5 DBE/November 2018 NSC/NSS – NSC/NSS – Marking Guidelines/Nasienriglyne 3.2.3 H O  ACCEPT/AANVAAR (2 or/of 0) H C O C H  H O H O Marking criteria/Nasienriglyne • Whole structure correct: H C C H  Hele struktuur korrek: 2 H 2 • Only functional group correct: Slegs funksionele groep korrek: Max/Maks: 1 O H 2 IF/INDIEN H C C O H  • More than one functional group/wrong functional group/Meer as een funksionele groep/foutiewe H funksionele groep: 0 2 • If condensed structural formulae used/Indien O HO H gekondenseerde struktuur-formules gebruik:  H C C H Max/Maks: 1 2 (2) 3.3 A - Lowest boiling point./Shortest chain length.  Laagste kookpunt./Kortste kettinglengte. (2) 3.4 3.4.1 The same molecular mass/molecular size.  Dieselfde molekulêre massa/molekulêre grootte. (1) 3.4.2 Primary/Primêre  -OH group is bonded to a C atom bonded to one other C atom.  -OH-groep is gebind aan 'n C-atoom wat aan een ander C-atoom gebind is. OR/OF -OH group is bonded to a C atom that has two H atoms. -OH-groep is gebind aan 'n C-atoom wat twee H-atome bevat. (2) Copyright reserved/Kopiereg voorbehou Please turn the page/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 6 DBE/November 2018 NSC/NSS – NSC/NSS – Marking Guidelines/Nasienriglyne 3.4.3 Marking guidelines/Nasienriglyne • BOTH have hydrogen bonding./BEIDE het waterstofbindings.  • Compare number of sites for hydrogen bonding./Vergelyk aantal punte vir waterstofbinding.  • Compare strength of IMFs./Vergelyk sterkte van IMKe.  • Compare energy required./Vergelyk energie benodig.  • Both compounds/X and B have (in addition to London forces and dipole- dipole forces) hydrogen bonding./Beide verbindings/X en B het waterstofbindings (behalwe Londonkragte en dipool-dipoolkragte).  • Compound X/CH 3 CH 2 CH 2 OH/propan-1-ol/alcohol has one site for hydrogen bonding and compound B/ethanoic acid/carboxylic acid has two/more sites for hydrogen bonding OR B/ethanoic acid/carboxylic acid has two/more sites for hydrogen bonding.  Verbinding X/CH 3 CH 2 CH 2 OH/propan-1-ol/alkohol het een punt vir waterstofbindings en verbinding B/etanoësuu/karboksielsuur het twee/meer punte vir waterstofbindings OF B/etanoësuu/karboksielsuur het twee/meer punte vir waterstofbindings. • Intermolecular forces in compound B/ethanoic acid/carboxylic acid are stronger than intermolecular forces in compound X/CH 3 CH 2 CH 2 OH/ propan-1-ol/alcohol.  Intermolekulêre kragte in verbinding B/etanoësuur/karboksielsuur is sterker as die intermolekulêre kragte in verbinding X/CH 3 CH 2 CH 2 OH/ propan-1-ol/alkohol. OR/OF Intermolecular forces in compound X/CH 3 CH 2 CH 2 OH/ propan-1- ol/alcohol are weaker than intermolecular forces in compound B/ethanoic acid/carboxylic acid./Intermolekulêre kragte in verbinding X/CH 3 CH 2 CH 2 OH/propan-1-ol/alkohol is swakker as intermolekulêre kragte in verbinding B/etanoësuur/karboksielsuur. • More energy is needed to overcome/break intermolecular forces in compound B/ethanoic acid/carboxylic acid than in compound X/CH 3 CH 2 CH 2 OH/ propan-1-ol/alcohol.  Meer energie word benodig om intermolekulêre kragte in verbinding B/etanoësuur as in verbinding X/CH 3 CH 2 CH 2 OH/ propan-1-ol/alkohol te oorkom/breek. OR/OF Less energy is needed to overcome/break intermolecular forces in compound X/CH 3 CH 2 CH 2 OH/propan-1-ol/alcohol than in compound B/ethanoic acid/carboxylic acid. Minder energie word benodig om intermolekulêre kragte in verbinding X/ CH 3 CH 2 CH 2 OH/propan-1-ol/alkohol te oorkom/breek as in verbinding B/etanoësuur/karboksielsuur. (4) [15] Copyright reserved/Kopiereg voorbehou Please turn the page/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 7 DBE/November 2018 NSC/NSS – NSC/NSS – Marking Guidelines/Nasienriglyne QUESTION 4/VRAAG 4 4.1 4.1.1 (A series of organic) compounds that can be described by the same general formula/functional group.  (2 or 0) ('n Reeks organiese) verbindings wat deur dieselfde algemene formule/ funksionele groep beskryf kan word. (2 of 0) OR/OF (A series of organic) compounds in which one member differs from the next by a CH 2 group./('n Reeks organiese) verbindings waarin een lid van die volgende verskil met 'n CH 2 -groep. (2 or/of 0) (2) 4.1.2 Substitution/halogenation/bromination  Substitusie/halogenasie/halogenering/brominasie/brominering (1) 4.1.3 HBr  (1) 4.1.4  Marking criteria/Nasienriglyne Br H H H  • Br on first C atom/Br op eerste C- H C C C C H atoom: Max/Maks: 1 2 • Whole structure correct/Hele struktuur H H H H korrek: 2 2 IF/INDIEN: Br 2 but rest of structure correct/Br 2 maar res van struktuur korrek: 1 2 (2) 4.1.5 C 5 H 12 + 8O 2   5CO 2 + 6H 2 O  Bal  Marking guidelines/Nasienriglyne • Reactants  Products  Balancing  Reaktanse Produkte Balansering • Ignore double arrows and phases./Ignoreer dubbelpyle en fases. • Marking rule 6.3.10/Nasienreël 6.3.10. • If condensed structural formulae used/Indien gekondenseerde struktuur- formules gebruik: Max/Maks: 2 3 (3) 4.1.6 Marking guidelines/Nasienriglyne If any one of the underlined key phrases in the correct context is omitted, deduct 1 mark./Indien enige van die onderstreepte frases in die korrekte konteks uitgelaat is, trek 1 punt af. The (chemical) process in which longer chain hydrocarbons/longer chain alkanes are broken down to shorter/more useful hydrocarbons/molecules/ chains/alkanes and alkenes. Die (chemiese) proses waarin langketting koolwaterstowwe/langketting- alkane afgebreek word in korter/meer bruikbare koolwaterstowwe/molekule/ kettings/alkane en alkene. (2) Copyright reserved/Kopiereg voorbehou Please turn the page/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 8 DBE/November 2018 NSC/NSS – NSC/NSS – Marking Guidelines/Nasienriglyne 4.1.7 H H H H Marking guidelines/Nasienriglyne  • One or more H atoms omitted/Een of H C C C C H meer H-atome uitgelaat: Max/Maks: 1 2 • Condensed or semi-structural formula: H H H H Gekondenseerde of semi-struktuur- formule: Max/Maks: 1 2 (2) 4.2 4.2.1 Butan-2-ol  OR/OF 2-butanol  IF/INDIEN: Butanol or/of butan-1-ol 1 2 (2) 4.2.2 H  H H Marking criteria/Nasienriglyne  • Only functional group correct/Slegs H C C C C H funksionele groep korrek: Max/Maks: 1 2 H H H • Whole structure correct: Hele struktuur korrek: 2 2 (2) [17] QUESTION 5/VRAAG 5 5.1 Temperature/Temperatuur  (1) 5. 2 NOTE/LET WEL Give the mark for per unit time only if in context of reaction rate. Gee die punt vir per eenheidtyd slegs indien in konteks met reaksietempo. ANY ONE/ENIGE EEN • Change in concentration  of products/reactants per (unit) time.  Verandering in konsentrasie van produkte/reaktanse per (eenheid) tyd. • Change in amount/number of moles/volume/mass of products or reactants per (unit) time. Verandering in hoeveelheid/getal mol/volume/massa van produkte of reaktanse per (eenheid) tyd. • Amount/number of moles/volume/mass of products formed/reactants used per (unit) time. Hoeveelheid/getal mol/volume/massa van produkte gevorm/reaktanse gebruik per (eenheid) tyd. • Rate of change in concentration/amount/number of moles/volume/mass. Tempo van verandering in konsentrasie/ hoeveelheid/getal mol/ volume/massa.  (2 or/of 0) (2) 5.3 14 (min)  (2) Copyright reserved/Kopiereg voorbehou Please turn the page/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 9 DBE/November 2018 NSC/NSS – NSC/NSS – Marking Guidelines/Nasienriglyne 5.4 5.4.1 B - Graph/grafiek (Experiment 3) has the highest (acid) concentration/more particles/higher number of moles.  (Eksperiment 3) het die hoogste (suur)konsentrasie/meer deeltjies/groter aantal mol. (2) 5.4.2 C - (Graph/grafiek) (Experiment 5) is at highest temperature/more particles with sufficient kinetic energy/HCℓ is at 35oC  (Eksperiment 5) is by die hoogste temperatuur/meer deeltjies met genoeg kinetiese energie/HCℓ is by 35oC. (2) 5.5 5.5.1 Speeds up the reaction./Increases the reaction rate./Provides alternate pathway./Lowers the (net) activation energy.  Versnel die reaksie./Verhoog die reaksietempo./Verskaf alternatiewe roete./Verlaag die (netto) aktiveringsenergie. (1) 5.5.2 Equal to/Gelyk aan  (1) 5.6 m Marking guidelines/Nasienriglyne n( Zn) = • Substitute/vervang 65 g∙mol-1 in M 1,5 m n=  = M 65  • Substitute change in mol to calculate = 0,023 mol rate./Vervang verandering in mol om ∆n tempo te bereken.  rate/tempo = − ∆t  • Substitute change in time to calculate 0 - 0,023 rate./Vervang verandering in tyd om =-( ) tempo te bereken.  14- 0 • Final answer/Finale antwoord: = 1,65 x 10-3 (mol·min-1) 1,65 x 10-3 mol∙min-1   Range/Gebied: 1,43 x 10-3 to/tot 1,65 x 10-3 (mol∙min-1) Notes/Aantekeninge • Ignore if zeros omitted in calculation of reaction rate./Ignoreer indien nulle uitgelaat in berekening van reaksietempo. • Accept negative answer i.e. -1,65 x 10-3 mol·min-1/Aanvaar negatiewe antwoord d.i. -1,65 x 10-3 mol·min-1. (4) [15] Copyright reserved/Kopiereg voorbehou Please turn the page/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 10 DBE/November 2018 NSC/NSS – NSC/NSS – Marking Guidelines/Nasienriglyne QUESTION 6/VRAAG 6 6.1 When the equilibrium in a closed system is disturbed, the system will re- instate a (new) equilibrium  by favouring the reaction that will cancel/oppose the disturbance.  Wanneer die ewewig in 'n geslote sisteem versteur word, sal die sisteem 'n (nuwe) ewewig instel deur die reaksie te bevoordeel wat die versteuring kanselleer/teenwerk. (2) 6.2 Endothermic/Endotermies  - • Decrease in temperature favours the exothermic reaction.  Afname in temperatuur bevoordeel die eksotermiese reaksie. • The reverse reaction is favoured./Die terugwaartse reaksie word bevoordeel.  OR/OF Number of moles/amount/concentration of N 2 O 4 /colourless gas increases. Aantal mol/hoeveelheid/konsentrasie van N 2 O 4 /kleurlose gas neem toe. OR/OF Number of moles/amount of NO 2 /brown gas decreases./Aantal mol/ hoeveelheid NO 2 /bruin gas neem af. (3) 6.3 6.3.1 Increases/Verhoog  (1) 6.3.2 Remains the same/Bly dieselfde  (1) 6.3.3 Increases/Verhoog  (1) Copyright reserved/Kopiereg voorbehou Please turn the page/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 11 DBE/November 2018 NSC/NSS – NSC/NSS – Marking Guidelines/Nasienriglyne 6.4 CALCULATIONS USING NUMBER OF MOLES BEREKENINGE WAT GETAL MOL GEBRUIK Marking guidelines/Nasienriglyne • ∆n(N 2 O 4 ) = 20% of/van x/0,2x.  • USE ratio/GEBRUIK verhouding: N 2 O 4 : NO 2 : = 1 : 2.  • n(N 2 O 4 ) eq/ewe = n(N 2 O 4 ) initial/begin - ∆n(N 2 O 4 ). n(NO 2 ) eq/ewe = n(NO 2 ) initial/begin + ∆n(NO 2 ).  • Divide equilibrium moles by 2 dm3/Deel ewewigsmol deur 2 dm3.  • Correct K c expression (formulae in square brackets).  Korrekte K c uitdrukking (formules in vierkanthakies). • Substitution of K c value/Vervanging van K c -waarde.  • Substitution of concentrations into correct K c expression.  Vervanging van konsentrasies in korrekte K c -uitdrukking. • Final answer/Finale antwoord: 1,6 (mol)  OPTION 1/OPSIE 1 N2O4 NO 2 Initial amount (moles) x 0 Aanvangshoeveelheid (mol) Change in amount (moles) 0,2x  0,4x ratio  Verandering in hoeveelheid (mol) verhouding Equilibrium amount (moles) 0,8x 0,4x  hoeveelheid (mol) Equilibrium concentration (mol∙dm-3) Divide by 0,4x 0,2x Ewewigskonsentrasie (mol∙dm-3) 2 dm3  [NO 2 ] 2 No Kc expression, correct substitution/Geen Kc- Kc =  uitdrukking, korrekte substitusie: Max./Maks. 7 [N2 O 4 ] 8 2 (0,2x ) Wrong Kc expression/Verkeerde Kc-uitdrukking: 0,16 =  (0,4x ) Max./Maks. 5 8 x = 1,6 (mol ) OPTION 2/OPSIE 2 20 ∆n(N 2 O 4 ) = x  = 0,2x 100 ∆n(NO 2 ) = 2∆n(N 2 O 4 ) = 0,4 x  n(N 2 O 4 ) eq/ewe = x – 0,2x = 0,8x AND n(NO 2 ) eq/ewe = 0 + 0,4x  0,8x c(N 2 O 4 ) eq/ewe = = 0,4x 2  0,4x c(NO 2 ) eq/ewe = = 0,2x 2 [NO 2 ] 2 No Kc expression, correct substitution/Geen Kc- Kc =  uitdrukking, korrekte substitusie: Max./Maks. 7 [N2 O 4 ] 8 (0,2x )2 Wrong Kc expression/Verkeerde Kc-uitdrukking: 0,16 =  (0,4 x ) Max./Maks. 5 8 x = 1,6 (mol ) Copyright reserved/Kopiereg voorbehou Please turn the page/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 12 DBE/November 2018 NSC/NSS – NSC/NSS – Marking Guidelines/Nasienriglyne CALCULATIONS USING CONCENTRATION BEREKENINGE WAT KONSENTRASIE GEBRUIK Marking guidelines/Nasienriglyne • Initial n(N 2 O 4 )/x divide by 2 dm3.  Aanvanklike n(N 2 O 4 )/x gedeel deur 2 dm3. • ∆c(N 2 O 4 ) = 20% of initial concentration/0,1x.  • USE ratio/GEBRUIK verhouding: c(N 2 O 4 ) : c(NO 2 ) = 1 : 2.  • c(N 2 O 4 ) eq/ewe = c(N 2 O 4 ) initial/begin - ∆c(N 2 O 4 ). c(NO 2 ) eq/ewe = c(NO 2 ) initial/begin + ∆c(NO 2 ).  • Correct K c expression (formulae in square brackets).  Korrekte K c uitdrukking (formules in vierkanthakies). • Substitution of K c value/Vervanging van K c -waarde.  • Substitution of concentrations into K c expression.  Vervanging van konsentrasies in K c -uitdrukking. • Final answer/Finale antwoord: 1,6 (mol)  OPTION 3/OPSIE 3 N2O4 NO 2 Initial concentration (mol∙dm-3) x = 0,5x 0 Divide by 2 dm3  Aanvanklike konsentrasie (mol∙dm-3) 2 Change (mol∙dm-3) ratio  0,1x  0,2x verhouding Verandering (mol∙dm-3) Equilibrium concentration (mol∙dm-3) 0,4x 0,2x  Ewewigskonsentrasie (mol∙dm-3) No Kc expression, correct substitution/Geen Kc- [NO 2 ] 2 Kc =  uitdrukking, korrekte substitusie: Max./Maks. 6 [N2 O 4 ] 8 (0,2x ) 2 Wrong Kc expression/Verkeerde Kc-uitdrukking: 0,16  =  0,4x Max./Maks. 5 8 x = 1,6 (mol ) (8) [16] Copyright reserved/Kopiereg voorbehou Please turn the page/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 13 DBE/November 2018 NSC/NSS – NSC/NSS – Marking Guidelines/Nasienriglyne QUESTION 7/VRAAG 7 7.1 7.1.1 An acid is a proton donor.  'n Suur is 'n protondonor/skenker. (2) 7.1.2 H2O  (1) 7.1.3 HSO −4  (2) 7.2 7.2.1 Reaction of a salt with water/H 2 O.  Reaksie van 'n sout met water/H 2 O. Accept/Aanvaar Reaction of cations or anions with water Reaksie van katione of anione met water (2) 7.2.2 • CO 32− (aq) + 2H 2 O(ℓ)  ⇌ H 2 CO 3 (aq) + 2OH − (aq)  OR/OF CO 32− (aq) + H 2 O(ℓ) ⇌ HCO 3− (aq) + OH − (aq) Accept/Aanvaar: Ca CO 3 (aq) + 2H 2 O(ℓ) ⇌ H 2 CO 3 (aq) + Ca(OH) 2 (aq) • The formation of OH − (aq) neutralises the excess acid.  Die vorming van OH − (aq) neutraliseer die oormaat suur. Marking guidelines/Nasienriglyne • Reactants  Products  Reaktanse Produkte • The formation of OH − (aq) neutralises the excess acid.  Die vorming van OH − (aq) neutraliseer die oormaat suur. • Ignore single arrows and phases./Ignoreer enkelpyle en fases. • Marking rule 6.3.10/Nasienreël 6.3.10. • Ignore balancing./Ignoreer balansering. (3) 7.3 7.3.1 pH = -log[H 3 O+]  5  = -log[H 3 O+] [H 3 O+] = 1 x 10-5 mol·dm-3  (3) Copyright reserved/Kopiereg voorbehou Please turn the page/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 14 DBE/November 2018 NSC/NSS – NSC/NSS – Marking Guidelines/Nasienriglyne 7.3.2 POSITIVE MARKING FROM QUESTION 7.3.1. POSITIEWE NASIEN VAN VRAAG 7.3.1. Marking guidelines/Nasienriglyne n m c a × Va n m • Any formula/Enige formule: c = /n = / = a /c =  V M c b × Vb nb MV 9 3 • Substitute/vervang V = 4 x 10 dm  • Calculate n a (reacted) = n a (initial) – n a (final)  Bereken n a (reageer) = n a (begin) – n a (finaal) • Use/Gebruik n(CaO) : n(H 3 O+) = 1:2  • Substitution of/Vervanging van 56 g∙mol-1  • Final answer/Finale antwoord: m = 1,08 x 106 g to/tot 1,09 x 106 g  IF final answer is negative:/INDIEN finale antwoord negatief is Max/Maks: 6 7 OPTION 1/OPSIE 1 OPTION 2/OPSIE 2 n n c(H 3 O+) ini/aanv. =  c(H 3 O+) fin =  V V n 1,26 × 10 3 1 x 10-5 = = 4 × 10 9  4 × 10 9  n a = 4 x 104 mol = 3,15 x 10-7 mol∙dm-3 n(H 3 O+) react/rea c(H 3 O+) rea = 1 x 10-5 – 3,15 x 10-7  = 4 x 104 – 1,26 x 103  = 9,69 x 10-6 mol∙dm-3 = 3,87 x 104 mol n(H 3 O+) rea = cV n(CaO) = ½n(H 3 O+) = (9,65 x 10-6)(4 x 109) = ½ x 3,87 x 104  = 3,87 x 104 mol = 1,94 x 104 mol n(CaO) = ½n(H 3 O+) = ½ x 3,87 x 104  = 1,94 x 104 mol OR/OF m 1 mol : 56 g  n(CaO) = M m 1,94 x 104 mol : m 1,94 x 104 = ∴ m = 1,09 x 106 g  56 ∴ m = 1,09 x 106 g  OPTION 3/OPSIE 3 n c(H 3 O+) fin =  V 1,26 × 10 3 = 4 × 10 9  = 3,15 x 10-7 mol∙dm-3 c(H 3 O+) rea = 1 x 10-5 – 3,15 x 10-7  = 9,69 x 10-6 mol∙dm-3 c(CaO) = ½c(H 3 O+)  = 4,845 x 10-6 mol∙dm-3 m m c = ∴ 4,845 x 10-6 = ∴ m = 1,09 x 106 g  MV 56( 4 × 10 ) 9 (7) [20] Copyright reserved/Kopiereg voorbehou Please turn the page/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 15 DBE/November 2018 NSC/NSS – NSC/NSS – Marking Guidelines/Nasienriglyne QUESTION 8/VRAAG 8 8.1 8.1.1 Loss of electrons./Verlies aan elektrone.  (2 or/of 0) (2) 8.1.2 Fe → Fe3+ + 3e-  Marking guidelines/Nasienriglyne • Fe ⇌ Fe3+ + 3e- 1 Fe3+ + 3e- ⇌ Fe 0 2 2 3+ -- Fe + 3e ← Fe 2 3+ - Fe + 3e → Fe 0 2 2 • Ignore if charge omitted on electron./Ignoreer indien lading weggelaat op elektron. • If charge (+) omitted on Fe3+/Indien lading (+) weggelaat op Fe3+: Example/Voorbeeld: Fe → Fe3 + 3e-  Max./Maks: 1 2 (2) 8.1.3 Reducing agent/Reduseermiddel  (1) 8.1.4 Fe is a stronger reducing agent  than Cu  and (Fe) will be oxidised  (to Fe3+)./Fe is 'n sterker reduseermiddel as Cu en (Fe) sal geoksideer word (na Fe3+). OR/OF Cu is a weaker reducing agent  than Fe and (Cu) will not be oxidised  (to Cu2+)./Cu is 'n swakker reduseermiddel as Fe en (Cu) sal nie geoksideer word nie (na Cu2+). (3) 8.1.5 - Zinc/Zn  Stronger reducing agent (than Fe)./Sterker reduseermiddel (as Fe).  OR/OF Zn will undergo oxidation (before Fe)./Zn sal oksidasie (voor Fe) ondergaan. OR/OF Cu is a weaker reducing agent (than Fe)./Cu is 'n swakker reduseermiddel (as Fe). (2) 8.2 8.2.1 3Cu2+ + 2Fe  → 3Cu + 2Fe3+  Bal.  Marking guidelines/Nasienriglyne • Reactants  Products  Balancing  Reaktanse Produkte Balansering • Ignore double arrows./Ignoreer dubbelpyle. • Marking rule 6.3.10/Nasienreël 6.3.10. (3) Copyright reserved/Kopiereg voorbehou Please turn the page/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 16 DBE/November 2018 NSC/NSS – NSC/NSS – Marking Guidelines/Nasienriglyne 8.2.2 OPTION 1/OPSIE 1 Notes/Aantekeninge θ E cell θ = E reduction θ − E oxidation  • Accept any other correct formula from the data sheet./Aanvaar enige ander korrekte formule = 0,34  – (-0,06)  vanaf gegewensblad. = 0,40 V  • Any other formula using unconventional abbreviations, e.g. E° cell = E° OA - E° RA followed by correct substitutions:/Enige ander formule wat onkonvensionele afkortings gebruik bv. E° sel = E° OM - E° RM gevolg deur korrekte vervangings : 3 4 OPTION 2/OPSIE 2 Cu2+ + 2e- → Cu  E θ = 0,34 V  Fe → Fe3+ + 3e- E θ = 0,06 V  3Cu2+ + 2Fe → 3Cu + 2Fe3+ E θ = +0,40 V  (4) [17] QUESTION 9/VRAAG 9 9.1 A cell in which electrical energy is converted to chemical energy.  (2 or 0) 'n Sel waarin elektriese energie omgeskakel word na chemiese energie. (2 of 0) OR/OF A cell in which electrical energy/electricity is used to obtain a chemical change/reaction. (2 or 0) 'n Sel waarin elektriese energie/elektrisiteit gebruik word om 'n chemiese verandering/reaksie te veroorsaak. (2 of 0) (2) 9.2 Any soluble copper(II) salt e.g./Enige oplosbare koper(II)-sout bv. CuSO 4 /Cu(NO 3 ) 2 /CuCℓ 2  (1) 9.3 B Cu2+ + 2e- → Cu  Marking guidelines/Nasienriglyne • Cu ← Cu2+ + 2e- (2 ) Cu ⇌ Cu2+ + 2e- ( 0 ) 2 2 2+ Cu + 2e ⇌ Cu- ( 1 ) 2+ Cu → Cu + 2e - ( 0 ) 2 2 • Ignore if charge on electron is omitted./Ignoreer indien lading op elektron uitgelaat is. 2 - • If a charge of an ion is omitted e.g. Cu + 2e → Cu /Indien lading op ioon Max./Maks: 1 2 - uitgelaat is bv. Cu + 2e → Cu (3) 2 9.4 Platinum/Pt  AND/EN silver/Ag/silwer  (2) [8] Copyright reserved/Kopiereg voorbehou Please turn the page/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 17 DBE/November 2018 NSC/NSS – NSC/NSS – Marking Guidelines/Nasienriglyne QUESTION 10/VRAAG 10 10.1 10.1.1 Haber (process)/Haber(proses)  (1) 10.1.2 Ostwald (process)/Ostwald(proses)  (1) 10.2 10.2.1 Ammonium nitrate/Ammoniumnitraat/NH 4 NO 3  (1) 10.2.2 Iron/iron oxide/Fe/FeO  Yster/ysteroksied/Fe/FeO (1) 10.3 2NH 3 + H 2 SO 4  → (NH 4 ) 2 SO 4  Bal  (3) Marking guidelines/Nasienriglyne • Reactants  Products  Balancing  Reaktanse Produkte Balansering • Ignore double arrows./Ignoreer dubbelpyle. • Marking rule 6.3.10./Nasienreël 6.3.10. 10.4 Marking guidelines/Nasienriglyne • Any ONE molar mass correct/Enige EEN molêre massa korrek: 80 g∙mol-1/164 g∙mol-1/74,5 g∙mol-1  • m(N) = 7 (kg) OR/OF 0,14  • m(P) = 2,27 (kg) OR/OF 0,045  • m(K) = 9,42 (kg) OR/OF 0,188  • Final answer/Finale antwoord: 3 : 1 : 4  ACCEPT/AANVAAR: 3,08 : 1 : 4,15 OR/OF 7 : 2,27 : 9,42 OPTION 1/OPSIE 1 OPTION 2/OPSIE 2 NH 4 NO 3 : m n(NH 4 NO 3 ) = 80 g → 28 g N M 28 20 000 20 kg → x 20 = = 250 mol 80 80  ∴ m(N) = 7 kg  n(N) = 2n(NH 4 NO 3 ) = 500 mol Na 3 PO 4 : m(N) = 500 x 14 164 g → 31 g P = 7 000 g = 7 kg  31 12 kg → x 12 12 000 164 n(Na 3 PO 4 ) = = 73,17 mol 164 ∴ m(P) = 2,27 kg  m(P) = 73,17 x 31 KCℓ: = 2 268 g = 2,27 kg  74,5 g → 39 g K 18 000 39 n(KCℓ) = = 241,61 mol 18 kg → x 18 74,5 74,5 ∴ m(K) = 9,42 kg  m(K) = 241,61 x 39 = 9 423 g = 9,42 kg  ∴ N : P : K ∴ N : P : K 7 : 2,27 : 9,42 7 : 2,27 : 9,42 3 : 1 : 4  3 : 1 : 4  Copyright reserved/Kopiereg voorbehou Please turn the page/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 18 DBE/November 2018 NSC/NSS – NSC/NSS – Marking Guidelines/Nasienriglyne OPTION 3/OPSIE 3 OPTION 4/OPSIE 4 28 NH 4 NO 3 : NH 4 NO 3 : %N = x 100 = 35% 80 28 %N = x 100 = 35% 35 80  m(N) = × 20 = 7 kg  Na 3 PO 4 : 100 Na 3 PO 4 : 31 %P = x 100 = 18,9% 31 164 %P = x 100 = 18,9% KCℓ: 164 18,9 39 m(N) = × 12 = 2,27 kg  %K = x 100 = 52,34% 100 74,5 KCℓ: 20 N: x 35 = 0,14  39 50 %K = x 100 = 52,34% 74,5 12 P: x 18,9 = 0,045  52,34 50 m(K) = × 18 = 9,42 kg  100 18 K: x 52,34 = 0,188  ∴ N : P : K = 7 : 2,27 : 9,42 50 =3: 1 :4  N : P : K = 0,14 : 0,045 : 0,188 = 3 : 1 :4  (5) [12] TOTAL/TOTAAL: 150 Copyright reserved/Kopiereg voorbehou