Physical Sciences Grade 12 Paper 2 NSC June 2021 Memo

Downloaded from hlayiso.com SENIOR CERTIFICATE EXAMINATIONS/ NATIONAL SENIOR CERTIFICATE EXAMINATIONS SENIORSERTIFIKAAT-EKSAMEN/ NASIONALE SENIORSERTIFIKAAT-EKSAMEN PHYSICAL SCIENCES: CHEMISTRY (P2) FISIESE WETENSKAPPE: CHEMIE (V2) 2021 MARKING GUIDELINES/NASIENRIGLYNE MARKS/PUNTE: 150 These marking guidelines consist of 19 pages./ Hierdie nasienriglyne bestaan uit 19 bladsye. Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences/P2/Fisiese Wetenskappe/V2 2 DBE/2021 SC/NSC/SS/NSS – Marking Guidelines/Nasienriglyne QUESTION 1/VRAAG 1 1.1 C  (2) 1.2 D  (2) 1.3 C  (2) 1.4 B  (2) 1.5 D  (2) 1.6 C  (2) 1.7 B  (2) 1.8 B  (2) 1.9 A  (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/2021 SCE/NSC/SSE/NSS – Marking Guidelines/Nasienriglyne QUESTION 2/VRAAG 2 2.1 2.1.1 F (1) 2.1.2 B&F (1) 2.1.3 C (1) 2.2 2.2.1 Haloalkane / alkyl halide  Haloalkaan/alkielhalied (1) 2.2.2 3,5-dibromooctane  3,5-dibroomoktaan Marking criteria/Nasienkriteria:  Octane/Oktaan   Dibromo/Dibroom   Substituents (dibromo) correctly numbered, hyphens, commas correctly used./ Substituente (dibroom) korrek genommer, koppeltekens en kommas korrek gebruik.  (3) 2.3 2.3.1 Pentan-3-one  Marking criteria/Nasienkriteria: Pentan-3-oon  Pentanone/pentanoon  OR/OF  Correct position of functional group.  3-pentanone Korrekte posisie van funksionele groep. 3-pentanoon (2) 2.3.2 3-methylbutan-2-one/3-metielbutan-2-oon OR/OF 3-methylbutanone/3-metielbutanoon OR/OF methylbutanone/metielbutanoon OR/OF 3-methyl- 2-butanone/3-metiel-2-butanoon (2) 2.4 2.4.1 Hexyl methanoate  Heksielmetanoaat (2) 2.4.2 O O  OR/OF C O C R C O R (1) 2.5 2.5.1 Cracking/Elimination  Kraking/eliminasie (1) 2.5.2 C7H16  (2) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 4 DBE/2021 SCE/NSC/SSE/NSS – Marking Guidelines/Nasienriglyne 2.5.3 H H Notes/Aantekeninge   Functional group/Funksionele H C C C H groep:   Whole structure correct/Hele H H struktuur korrek:  (2) [19] QUESTION 3/VRAAG 3 3.1 Marking guidelines/Nasienkriteria: 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 pressure exerted by a vapour at equilibrium with its liquid in a closed system.  Die druk uitgeoefen deur 'n damp in ewewig met sy vloeistoffase in 'n geslote sisteem. (2) 3.2 Functional group/Type of intermolecular forces/Homologous series  Funksionele groep/Tipe intermolekulêre kragte/Homoloë reeks (1) 3.3 B (1) 3.4 Marking criteria/Nasienkriteria  State hydrogen bonding in A./Noem waterstofbinding in A.   State dipole-dipole forces in B./Noem dipool-dipoolkragte in B.  Compare strengths of IMFs./Vergelyk sterktes van IMKe.   Compare energies required./Vergelyk energieë benodig.   Compound A/butan-1-ol has hydrogen bonding (dipole-dipole and London forces) between molecules.   Compound B/butan-2-one has dipole-dipole forces (and London forces) between molecules.   Intermolecular forces in compound A/butan-1-ol are stronger than intermolecular forces in compound B/butan-2-one.  OR Intermolecular forces in compound B/butan-2-one are weaker than intermolecular forces in compound A/butan-1-ol.   More energy is needed to overcome/break intermolecular forces in compound A/butan-ol than in compound B/butan-2-one.   Verbinding A/butan-1-ol het waterstofbindings (dipool-dipoolkragte en Londonkragte) tussen molekule.  Verbinding B/butan-2-oon het dipool-dipoolkragte (en London kragte) tussen molekule.   Intermolekulêre kragte in verbinding A/butan-1-ol is sterker as intermolekulêre kragte in verbinding B/butan-2-oon. OF Intermolekulêre kragte in verbinding B/butan-2-oon is swakker as intermolekulêre kragte in verbinding A/butan-1-ol.  Meer energie is nodig om intermolekulêre kragte te oorkom/breek in verbinding A/butan-1-ol as in verbinding B/butan-2-oon. (4) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences/P2/Fisiese Wetenskappe/V2 5 DBE/2021 SC/NSC/SS/NSS – Marking Guidelines/Nasienriglyne 3.5 3.5.1 Boiling point (of compound A/butan-1-ol)  Kookpunt (van verbinding A/butan-1-ol) (1) 3.5.2 Gas  (1) 3.5.3 Marking criteria/Nasienkriteria: A  Curve C starts below curve A/Kurwe C begin onder Vapour pressure (kPa) C kurwe A.   Curve C remains below  curve A/ Kurwe C bly onder 101,3 kurwe A.  Accept/Aanvaar Dampdruk (kPa)  If C is labelled as B / Indien C as B benoem is  If graph below graph A is unlabelled /Indien grafiek Temperature/Temperatuur (°C) onder grafiek A nie benoemis nie Note/Let Wel If both graphs unlabelled / Indien beide grafiek nie benoem is nie: 0 marks / 0 punte (2) [12] Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 6 DBE/2021 SCE/NSC/SSE/NSS – Marking Guidelines/Nasienriglyne QUESTION 4/VRAAG 4 4.1 4.1.1 Heat/sunlight/ultraviolet light/radiation/light  Hitte/sonlig/ultravioletlig/straling/lig (1) 4.1.2 HBr/hydrogen bromide/waterstofbromied  (1) 4.1.3 Hydrolysis/hidrolise  (1) 4.1.4 H2O/water Accept/Aanvaar hydrogen oxide/waterstofoksied OR/OF NaOH/KOH/LiOH/sodium hydroxide/potassium hydroxide/lithium hydroxide NaOH/KOH/LiOH/Natriumhidroksied/kaliumhidroksied/litiumhidroksied (1) 4.1.5 2-bromopropane  2-bromopropaan (2) 4.2 Marking criteria/Nasienkriteria: (Mark bullets independently. / Sien kolpunte onafhanklik na.)  React chloroethane with (conc) NaOH or NaOH in ethanol.   Indicate heat/Δ (on the arrow) or as a reactant in the reaction of chloroethane.   Correct condensed formula for ethene as product.  Product NaCℓ in the reaction of chloroethane.   Product H2O in the reaction of chloroethane.   React ethene with H2.  Indicate Pt on the arrow of / at the reaction of ethene with H2.   Correct condensed formula of ethane as product.  .  Reageer chloroetaan met (gekons) NaOH of NaOH in etanol.  Dui hitte/Δ (op die pyl) of as ‘n reaktant in die reaksie van chloroetaan.   Korrekte gekondenseerde formule vir eteen as produk.   Produk NaCℓ in die reaksie van chloroetaan.  Produk H2O in die reaksie van chloroetaan.  Reageer eteen met H2   Dui Pt aan op die pyl / by die reaksie van eteen met H2.   Korrekte gekondenseerde formule vir etaan as produk.  + NaOH (in ethanol/etanol)  CH3CH2Cℓ + (conc/gekons) NaOH  ∆ CH2CH2  + NaCℓ  + H2O  Pt  CH2CH2 + H2  CH3CH3  Note/Let wel Any additional reactants or products: Deduct one mark per reaction Enige addisionele reaktanse of produkte: Trek een punt af per reaksie (8) [14] Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences/P2/Fisiese Wetenskappe/V2 7 DBE/2021 SC/NSC/SS/NSS – Marking Guidelines/Nasienriglyne QUESTION 5/VRAAG 5 5.1 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) 5.2  Time/tyd   Volume of gas/CO2/carbon dioxide (in gas syringe) Volume gas/CO2/koolstofdioksied (in gasspuit) OR/OF  Time taken for Aℓ2(CO3)3 to be used up.  Tyd geneem vir die Aℓ2(CO3)3 om opgebruik te word. Accept/Aanvaar Measure volume of gas/CO2 at regular time intervals.  Meet volume van gas/CO2 met gereelde tydintervalle. (2) 5.3 Experiment II/Eksperiment II:  More (HCℓ) particles per unit volume./More particles with correct orientation.   More effective collisions per unit time./Higher frequency of effective collisions.   Higher reaction rate.   Meer (HCℓ)-deeltjies per eenheid volume./Meer deeltjies met korrekte oriëntasie.  Meer effektiewe botsings per eenheid tyd./Hoër frekwensie van effektiewe botsings.  Hoër reaksietempo. (3) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 8 DBE/2021 SCE/NSC/SSE/NSS – Marking Guidelines/Nasienriglyne OR/OF Experiment I/Eksperiment I:  Less (HCℓ) particles per unit volume.   Less effective collisions per unit time./Lower frequency of effective collisions.   Lower reaction rate.   Minder (HCℓ) deeltjies per eenheidvolume.  Minder effektiewe botsings per eenheidtyd./ Laer frekwensie van effektiewe botsings.  Laer reaksietempo. 5.4 OPTION 1/OPSIE 1 Marking criteria/Nasienkriteria n  Substitute average rate and ∆t./ ave rate/gem tempo = - Vervang gemiddelde tempo en ∆t.  t  Substitute/Vervang ∆n.  n  0,016  4,4 x 10-3 = - f  Final answer/Finale antwoord: 2,5 ( 0) 0,005 (mol)   n[Aℓ2(CO3)3] = 0,005 (mol)  NOTE/LET WEL OPTION 2/OPSIE 2  Accept negative answers when the n negative sign in front of the formula is ave rate/gem tempo = omitted./Aanvaar negatiewe antwoord t wanneer die negatiewe teken voor die -3 n formule uitgelaat is. 4,4 x 10 = 2,5  Do not penalise if initial and final mole  values or time values are swopped. / Δn[Aℓ2(CO3)3] = 0,016 – 0,011  Moenie penaliseer indien aanvanklike = 0,005 mol  en finale molwaardes omgeruil is nie. OPTION 3/OPSIE 3 With reference to CO2/Met verwysing na CO2 n ave. rate/gem tempo = t n 4,4 x 10-3 = 2,5  Δn(CO2) = 0,011 mol n(CO2) : n(Aℓ2(CO3)3 3 : 1 0,011 : 3,67 x 10-3 mol  n(Aℓ2(CO3)3 left/oor = 0,016 - 3,67 x 10-3 = 1,23 x 10-2 mol  Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 9 DBE/2021 SCE/NSC/SSE/NSS – Marking Guidelines/Nasienriglyne OPTION 4/OPSIE 4 With reference to HCℓ/Met verwysing na HCℓ n ave. rate/gem tempo = t n 4,4 x 10-3 =  2,5  Δn(HCℓ) = 0,011 mol 0,011 n[Aℓ2(CO3)3] = = 0,0018 mol  6 n[Aℓ2(CO3)3] left/oor = 0,016 – 0,0018 = 0,0142 mol  OPTION 5/OPSIE 5 With reference to AℓCℓ3/Met verwysing na AℓCℓ3 n ave. rate/gem tempo = t n 4,4 x 10-3 =  2,5  Δn(AℓCℓ3) = 0,011 mol n[Aℓ2(CO3)3] = 0,0055 mol  n[Aℓ2(CO3)3] left/oor = 0,016 – 0,0055 = 0,0105 mol  (3) 5.5 Marking criteria/Nasienkriteria:  Use mol ratio/Gebruik molverhouding: n(CO2) : n(Aℓ2(CO3)3) = 3 : 1  3 -1 3 -1 V  Substitute 24 000 cm ∙mol /24 dm ∙mol in n = or in ratio.  VM V Vervang 24 000 cm3∙mol-1/24 dm3∙mol-1 in n = of in verhouding. VM  Final answer/Finale antwoord: 1 152 cm3 / 1,152 dm3  OPTION 1/OPSIE 1 OPTION 2/OPSIE 2 n(CO2) = 3n[Aℓ2(CO3)3] n(CO2) = 3n[Aℓ2(CO3)3] = 3(0,016)  = 3(0,016)  = 0,048 mol = 0,048 mol V n(CO2) = 1 mol ……………….24 000 cm3 VM 0,048 mol ………….V V  0,048 =  0,048  24000 24000 V(CO2) =  3 3 1 V(CO2) = 1 152 cm (1,152 dm )  = 1 152 cm3 (1,152 dm3)  (3) [13] Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 10 DBE/2021 SCE/NSC/SSE/NSS – Marking Guidelines/Nasienriglyne QUESTION 6/VRAAG 6 6.1 (The stage in a chemical reaction when the) rate of forward reaction equals the rate of reverse reaction.  (Die stadium in 'n chemiese reaksie wanneer die) tempo van die voorwaartse reaksie gelyk is aan die tempo van die terugwaartse reaksie. (2 or/of 0) OR/OF (The stage in a chemical reaction when the) concentrations of reactants and products remain constant. (Die stadium in 'n chemiese reaksie wanneer die) konsentrasies van reaktanse en produkte konstant bly. (2 or/of 0) (2) 6.2 6.2.1 X - ANY ONE/ENIGE EEN  The concentration of products increases (from 0 – 6 min.). Die konsentrasie van die produkte neem toe (van 0 - 6 min.).  The concentration of reactants decreases (from 0 – 6 min.). Die konsentrasie van die reaktanse neem af (van 0 – 6 min.).  No products were present initially.  Geen produkte was aanvanklik teenwoordig nie.  The curve begins at zero./Die kurwe begin by nul. (2) 6.2.2 Higher than/Hoër as  (1) 6.3 CALCULATIONS USING NUMBER OF MOLES BEREKENINGE WAT AANTAL MOL GEBRUIK Marking criteria/Nasienkriteria  Calculate/Bereken mol HI: n(HI)ini/aanv. = 1(0,5).   Use mol ratio/Gebruik molverhouding: 2:1:1 / n(HI) = 2n(H2) = 2n(I2).   n(H2)equilibrium/ewewig = n(H2)formed/gevorm  n(I2)equilibrium/ewewig = n(I2)formed/gevorm Note: If Δn not shown award mark for equal nequilibrium Let wel: Indien Δn nie aangedui is nie, ken punt toe vir gelyke newewig  n((HI)equilibrium/ewewig = n(HI)initial/aanvanklik - n(HI)change/verandering.   Divide n(HI)equil & n(H2)equil & n(H2)equil by 0,5 dm3.  Deel n(HI)ewewig & n(H2)ewewig & n(H2)ewewig deur 0,5 dm3.  Correct Kc expression (formulae in square brackets).  Korrekte Kc-uitdrukking (formules in vierkanthakies).  Substitute 0,04 into Kc expression.  Vervang 0,04 in Kc-uitdrukking.  Substitute equilibrium concentrations in Kc expression.  Vervang ewewigskonsentrasies in Kc-uitdrukking.  Final answer/Finale antwoord: 0,07 mol  Range/Gebied: 0,07 – 0,072 mol Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 11 DBE/2021 SCE/NSC/SSE/NSS – Marking Guidelines/Nasienriglyne OPTION 1/OPSIE 1 n(HI) = 1(0,5) = 0,5 mol HI H2 I2 Initial quantity (mol) 0,5  0 0 Aanvangshoeveelheid (mol) Change (mol) ratio  2x x x Verandering (mol) verhouding Quantity at equilibrium (mol)/  0,5-2x  x x Hoeveelheid by ewewig (mol) Equilibrium concentration (mol∙dm-3) 0,5 - 2x x x divide by 0,5  Ewewigskonsentrasie (mol∙dm-3) 0,5 0,5 0,5 deel deur 0,5 [H2 ][I2 ] No KC expression, correct substitution/Geen Kc- Kc =  [HI] 2 8 uitdrukking, korrekte substitusie: Max./Maks. x x 9  ( )( ) 0,5 0,5  Wrong KC expression /Verkeerde Kc-uitdrukking: 0,04 = 6 0,5 - 2x 2 Max./Maks. ( ) 9 0,5 x = 0,071 mol  CALCULATIONS USING CONCENTRATION BEREKENINGE WAT KONSENTRASIE GEBRUIK Marking criteria/Nasienkriteria:  Use initial/Gebruik aanvanklike c(HI) = 1 mol∙dm-3.   Use mol ratio/Gebruik molverhouding: 2 : 1: 1 / n(HI) = 2n(H2) = 2n(I2).   c(H2)equilibrium/ewewig = c(H2)formed/gevorm  c(I2)equilibrium/ewewig = c(I2)formed/gevorm Note: If Δc not shown award mark for equal cequilibrium Let wel: Indien Δc nie aangedui is nie, ken punt toe vir gelyke cewewig  c(HI)equilibrium/ewewig = c(HI)initial - c(HI)change.   Correct Kc expression (formulae in square brackets).  Korrekte Kc-uitdrukking (formules in vierkanthakies).  Substitution of 0,04 into Kc expression.  Vervang 0,04 in Kc-uitdrukking.  Substitution of equilibrium concentrations into Kc expression.  Vervanging van ewewigskonsentrasies in Kc-uitdrukking.  Multiply concentration by 0,5 dm3.  Vermenigvuldig konsentrasie met 0,5 dm3.  Final answer/Finale antwoord: 0,07 mol  Range/Gebied: 0,07 to/tot 0,072 mol Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 12 DBE/2021 SCE/NSC/SSE/NSS – Marking Guidelines/Nasienriglyne OPTION 2/OPSIE 2 HI H2 I2 -3 Initial concentration (mol∙dm ) 1 0 0 Aanvangskonsentrasie (mol∙dm-3) Change (mol∙dm-3) 2x x x Verandering (mol∙dm-3) Equilibrium concentration (mol∙dm-3) Ewewigskonsentrasie (mol∙dm-3) 1-2x  x x  [H2 ][I2 ] Kc =  No KC expression, correct substitution/Geen Kc- [HI] 2 8 uitdrukking, korrekte substitusie: Max./Maks.  ( x )( x ) 9 0,04 =  (1  2x )2 Wrong KC expression /Verkeerde Kc-uitdrukking: x = 0,143 mol∙dm-3 6 Max./Maks. 9 n(I2) = cV = 0,143 x 0,5  = 0,072 mol  (9) 6.4 6.4.1 Both forward and reverse/Beide voorwaartse en terugwaartse  (1) 6.4.2 Positive/Positief   The forward reaction is favoured.  Die voorwaartse reaksie word bevoordeel.  An increase in temperature favours the endothermic reaction.  'n Toename in temperatuur bevoordeel die endotermiese reaksie.  The forward reaction is endothermic.  Die voorwaartse reaksie is endotermies. (4) [19] Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 13 DBE/2021 SCE/NSC/SSE/NSS – Marking Guidelines/Nasienriglyne QUESTION 7/VRAAG 7 7.1 Standard solution/Standaardoplossing  (1) 7.2 7.2.1 Marking criteria/Nasienkriteria: m m n  Any one of the formulae/Enige een van die formules: c  /n /c   MV M V  Substitution of 40 g∙mol-1 into correct formula.  Vervanging van 40 g∙mol-1 in korrekte formule.  Substitution of 0,25 dm3 into correct formula.  Vervanging van 0,25 dm3 in korrekte formule.  Final answer/Finale antwoord: 0,2 mol∙dm-3  OPTION 1/OPSIE 1 OPTION 2/OPSIE 2 m m c  n MV M 2  2 40  0,25   40  Any one formula/ = 0,20 mol∙dm-3  = 0,05 mol enige formule  n c V 0,05  0,25  = 0,20 mol∙dm-3  (4) 7.2.2 POSITIVE MARKING FROM 7.2.1./POSITIEWE NASIEN VAN 7.2.1. OPTION 1/OPSIE 1 OPTION 2/OPSIE 2 [H3O+][OH-] = 1 x 10-14 pOH = -log[OH-]  [H3O+](0,2) = 1 x 10-14  = -log(0,2)  [H3O+] = 5 x 10-14 mol∙dm-3 = 0,6989 (0,7) pH = -log[H3O+]  pH + pOH = 14 = -log(5 x 10-14)  pH = 14 – 0,6989  = 13,30  = 13,30  (4) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 14 DBE/2021 SCE/NSC/SSE/NSS – Marking Guidelines/Nasienriglyne 7.3 POSITIVE MARKING FROM QUESTION 7.2. POSITIEWE NASIEN VANAF VRAAG 7.2. Marking criteria/Nasienkriteria:  Substitution to calculate n(NaOH)./Vervanging om n(NaOH) te bereken.   Use mol ratio/Gebruik molverhouding: n(HCℓ)excess/oormaat : n(NaOH) = 1 : 1.  m  Substitute/Vervang 100 g·mol-1 in n =  M  Use mol ratio Gebruik molverhouding: n(HCℓ)reacted/oormaat : n(CaCO3) = 2 : 1.   n(HCℓ)initial/aanvanklik = n(HCℓ) excess/oormaat + n(HCℓ) reacted/reageer   Substitute 0,05 dm3 to calculate either c(HCℓ)initial or c(HCℓ) reacted Vervang 0,05 dm3 om c(HCℓ)aanvanklik of c(HCℓ)reageer te bereken.  Final answer/Finale antwoord: 0,7 mol∙dm-3  Range/Gebied: 0,70 to/tot 0,90 mol∙dm-3 OPTION 1/OPSIE 1 OPTION 2/OPSIE 2 n(NaOH)used/gebruik = cbVb 25 2 n(NaOH)used/gebruik =   = 0,2 x 0,025  250 40 = 5 x 10-3 mol = 5 x 10-3 mol n(HCℓ)excess/oormaat = n(NaOH) = 5 x 10-3 mol  m n(CaCO3) = M 1,5 = 100  = 0,015 mol (0,02 mol) n(HCℓ)reacted/reageer = 2n(CaCO3) = 0,03 mol  (0,04 mol) n(HCℓ)ini/aanv. = 5 x 10-3 + 0,03  = 0,035 mol (0,045 mol) n c(HCℓ)ini/aanv = V 0,035 =  0,05 = 0,70 mol∙dm-3  (0,90 mol∙dm-3) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 15 DBE/2021 SCE/NSC/SSE/NSS – Marking Guidelines/Nasienriglyne OPTION 3/OPSIE 3 OPTION/OPSIE 4 c a Va na (NaOH)used/gebruik = cbVb  = (0,2)(0,025) c b Vb nb = 0,005 mol c a (0,05) 1   (0,2)(0,025) 1 n(HCℓ)excess/oormaat = n(NaOH) = 0,005 mol ca = c(HCℓ)excess/oormaat 0,005 = 0,1 mol·dm-3 c(HCℓ)excess/oormaat = 0,05 = 0,1 mol·dm-3 m n(CaCO3) = M 1,5 = 100  = 0,015 mol n(CaCO3) : n(HCℓ) = 1 : 2 n(HCℓ)reacted/reageer = 2(0,015)  = 0,03 mol n c(HCℓ)reacted/reageer = V 0,03 =  0,05 = 0,6 mol·dm-3 c(HCℓ)initial/aanvanklik = c(HCℓ)reacted/reageer + c(HCℓ)excess/oormaat = 0,6 + 0,1  = 0,7 mol·dm-3  (8) [17] Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 16 DBE/2021 SCE/NSC/SSE/NSS – Marking Guidelines/Nasienriglyne QUESTION 8/VRAAG 8 8.1 8.1.1 Gain of electrons./Opneem van elektrone.  (2 or/of 0) (2) 8.1.2 2H2O(ℓ) + 2e─  H2(g) + 2OH─(aq)  Ignore phases/Ignoreer fases. Marking criteria /Nasienkriteria:  H2(g) + 2OH─(aq) ← 2H2O(ℓ) + 2e─ (2 ) 2 2H2O(ℓ) + 2e ⇌ H2(g) + 2OH (aq) ─ ─ ( 1 ) 2 H2(g) + 2OH─(aq) ⇌ 2H2O(ℓ) + 2e─ (0 ) 2 ─ ─ 0 2H2O(ℓ) + 2e ← H2(g) + 2OH (aq) ( ) 2  Ignore if charge omitted on electron./Ignoreer indien lading weggelaat op elektron.  If charge (-) omitted on OH─/Indien lading (-) weggelaat op OH─: Example/Voorbeeld: 2H2O(ℓ) + 2e─  H2(g) + 2OH(aq)  Max./Maks: 1 2 (2) 8.1.3 2Na(s) + 2H2O(ℓ)   H2(g) + 2OH-(aq) + 2Na+(aq)  Bal  OR/OF 2Na(s) + 2H2O(ℓ)   H2(g) + 2NaOH(aq)  Bal  Ignore phases/Ignoreer fases. Marking criteria/Nasienkriteria:  Reactants  Products  Balancing  Reaktanse Produkte Balansering  Ignore double arrows./Ignoreer dubbelpyle.  Ignore phases/Ignoreer fases.  Marking rule 6.3.10./Nasienreël 6.3.10. (3) 8.1.4 Formation of hydroxide ions / OH- / sodium hydroxide/base/ alkaline/ pH > 7  Vorming van hidroksied / OH- / natriumhidroksied / basis / alkalies / pH > 7 (1) ─ 8.1.5 Cu is a weaker reducing agent  than H2 (and OH─)  and H2O will not be reduced  (to H2 and OH─). Cu is 'n swakker reduseermiddel as H2 (and OH─) en H2O sal nie gereduseer word nie na H2 (en OH─). ─ OR/OF H2 (and OH-) are stronger reducing agent  than Cu and H2O will not be reduced(to H2 and OH-). H2 (en OH-) is 'n sterker reduseermiddel as Cu en H2O sal nie gereduseer word (na H2 en OH-). (3) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 17 DBE/2021 SCE/NSC/SSE/NSS – Marking Guidelines/Nasienriglyne 8.2 8.2.1 Phase separator/boundary/difference  Fase skeiding/grens/verskil (1) 8.2.2 Chemical (energy) to electrical (energy)  Chemiese (energie) na elektriese (energie) (1) 8.2.3 OPTION/OPSIE 1 Notes/Aantekeninge  E cell   E reduction   E oxidation   Accept any other correct formula from the data sheet./Aanvaar enige ander korrekte formule = 0,77  - (-0,13)  vanaf gegewensblad.  E cell = 0,90 V   Any other formula using unconventional abbreviations, e.g. Eθcell = EθOA - EθRA followed by correct substitutions:/Enige ander formule wat onkonvensionele afkortings gebruik bv. Eθsel = EθOM - EθRM gevolg deur korrekte vervangings: Max/Maks: 3 4 OPTION/OPSIE 2 Pb(s)  Pb2+(aq) + 2e- 0,13 (V)   2Fe3+(aq) + 2e-  2Fe2+(aq) 0,77 (V)  2+ 3+ 2+ Pb (aq) + 2Fe (aq)  Pb(s) + 2Fe (aq) 0,90 V  (4) [17] QUESTION 9/VRAAG 9 9.1 Electrolytic (cell)/Elektrolitiese (sel)  - Cells have a battery/DC power source/ /Electrical energy is converted to chemical energy.  Selle het batterye/GS kragbron/ Elektriese energie is omgeskakel na chemiese energie. (2) 9.2 9.2.1 2Cℓ─  Cℓ2 + 2e─  Notes/Aantekeninge 2Cℓ─ ⇌ Cℓ2 + 2e─ ( 1 ) Cℓ2 + 2e─ ← 2Cℓ─ ( 2 ) 2 2 ─ ─ 0 ─ ─ 0 Cℓ2 + 2e ⇌ 2Cℓ ( ) 2Cℓ ← Cℓ2 + 2e ( ) 2 2  Ignore if charge omitted on electron./Ignoreer indien lading weggelaat op elektron.  If charge (-) omitted on Cℓ─/Indien lading (-) weggelaat op Cℓ─: Example/Voorbeeld: 2Cℓ(aq)  Cℓ2(g) + 2e─ Max./Maks: 1 2 (2) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 18 DBE/2021 SCE/NSC/SSE/NSS – Marking Guidelines/Nasienriglyne 9.2.2 Aℓ3+ + 3e─  Aℓ  Notes/Aantekeninge Aℓ3+ + 3e─ ⇌ Aℓ ( 1 ) Aℓ ← Aℓ3+ + 3e─ ( 2 ) 2 2 ─ 0 0 Aℓ ⇌ Aℓ + 3e 3+ ( ) 3+ Aℓ + 3e ← Aℓ ( ) 2 2  Ignore if charge omitted on electron./Ignoreer indien lading weggelaat op elektron.  If charge (+) omitted on Aℓ3+ /Indien lading (+) weggelaat op Aℓ3+: Example/Voorbeeld: Aℓ3(aq) + 3e─  Aℓ(s) Max./Maks: 1 2 (2) 9.2.3 Cu/copper/koper  (1) 9.3 ANY ONE/ENIGE EEN  The electrode/carbon/C reacts with oxygen.  Die elektrode/koolstof/C reageer met suurstof.  C + O2  CO2  Oxidation takes place./Electrons are lost. Oksidasie vind plaas./Elektrone word verloor.  Oxygen corrodes the carbon electrode. Suurstof roes die koolstof elektrode. (1) [8] QUESTION 10/VRAAG 10 10.1 10.1.1 Sulphur dioxide/SO2/swaweldioksied  (1) 10.1.2 Sulphur trioxide/SO3/swaweltrioksied  (1) 10.1.3 Vanadium pentoxide/V2O5/ Vanadium(V) oxide  Vanadiumpentoksied/Vanadium(V) oksied (1) 10.1.4 H2SO4 + 2NH3   (NH4)2SO4  bal  Marking guidelines/Nasienkriteria:  Reactants  Products  Balancing  Reaktanse  Produkte  Balansering   Ignore/Ignoreer → and phases / en fases  Marking rule 6.3.10/Nasienreël 6.3.10 (3) 10.2 10.2.1 The ratio of nitrogen (N), phosphorous (P) and potassium (K) in a fertiliser./The ratio of the primary nutrients  Die verhouding van stikstof (N), fosfor (P) en kalium (K) in die kunsmis. / Die verhouding van primêre nutriënte. (1) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences/P2/Fisiese Wetenskappe/V2 19 DBE/2021 SC/NSC/SS/NSS – Marking Guidelines/Nasienriglyne 10.2.2 OPTION 1/OPSIE 1 Mass N in 4 kg NH4NO3 / Massa N in 4 kg NH4NO3 28 m(N) = x4 80 = 1,4 kg m(K) = 2m(N)  = 2,8 kg m(P) = 3m(N)  = 4,2 kg m(fertiliser/kunsmis) = 1,4 + 2,8 + 4,2 = 8,4 kg  OPTION 2/OPSIE 2 Mass N in 4 kg NH4NO3/Massa N in 4 kg NH4NO3: 28 m(N) = x4 80 = 1,4 kg N:P:K 1:3 :2 ∴ m(fertiliser/kunsmis) = (6)(1,4) = 8,4 kg  OPTION 3/OPSIE 3 (2)(14) %N= x 100 = 35% 80 Nitrogen in 4 kg = 35% of/van 4 = 1,4 kg  N : P : K 1 : 3 : 2 1,4 : 4,2 : 2,8  Total mass of fertiliser /Totale massa kunsmis = 1,4 + 4,2 + 2,8 = 8,4 kg  (4) [11] TOTAL/TOTAAL: 150 Copyright reserved/Kopiereg voorbehou