Physical Sciences Grade 12 Paper 2 NSC June 2022 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) 2022 MARKING GUIDELINES/NASIENRIGLYNE MARKS/PUNTE: 150 These marking guidelines consist of 16 pages./ Hierdie nasienriglyne bestaan uit 16 bladsye. Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 2 DBE/2022 SC/NSC/SS/NSS – Marking Guidelines/Nasienriglyne QUESTION 1/VRAAG 1 1.1 B  (2) 1.2 D  (2) 1.3 B  (2) 1.4 D  (2) 1.5 B  (2) 1.6 D  (2) 1.7 C  (2) 1.8 A  (2) 1.9 A  (2) 1.10 B  (2) [20] QUESTION 2/VRAAG 2 2.1 2.1.1 E (1) 2.1.2 F (1) 2.1.3 C (1) 2.1.4 H (1) 2.2 2.2.1 2-bromo-2,4,5-trimethylhexane/2-broom-2,4,5-trimetielheksaan Marking criteria: Nasienkriteria:  Correct stem i.e. hexane.   Korrekte stam d.i. heksaan.   All substituents (bromo and trimethyl)  Alle substituente (bromo and trimetiel) correctly identified.  korrek geïdentifiseer.   IUPAC name completely correct  IUPAC-naam heeltemal korrek including numbering, sequence, insluitende volgorde, koppeltekens en hyphens and commas.  kommas.  (3) Copyright reserved/Kopiereg voorbehou

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 3 DBE/2022 SC/NSC/SS/NSS – Marking Guidelines/Nasienriglyne 2.2.2 H Marking criteria/Nasienkriteria:  Five C atoms in longest chain + triple H C H bond.  H H Vyf C-atome in langste ketting +  drievoudige binding.   Two methyl substituents.  H C C C C C H  Twee metielsubstituente.  Whole structure correct. H H Hele struktuur korrek.  H C H H IF/INDIEN  More than one functional group/wrong functional group: Meer as een funksionele groep/foutiewe funksionele groep: 0 3  If condensed structural formulae used/Indien gekondenseerde struktuurformules gebruik: Max/Maks.: 2 3 (3) 2.3 2.3.1 Aldehyde/Aldehied  (1) 2.3.2 Formyl/Formiel  (1) 2.3.3 H H O H Marking criteria/Nasienkriteria:  Functional group.  H C C C C H Funksionele groep.  Whole structure correct. H H H Hele struktuur korrek.  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 struktuurformules gebruik: Max/Maks.: 1 2 (2) 2.4 2.4.1 Methylpropane/2-methylpropane/Metielpropaan/2-metielpropaan (2) 2.4.2 2C4H10 + 13O2  → 8CO2 + 10H2O  Bal.  Ignore phases./Ignoreer fases. Marking criteria/Nasienkriteria:  Reactants  Products  Balancing:  Reaktanse Produkte Balansering  Ignore double arrows./Ignoreer dubbelpyle.  Marking rule 6.3.10/Nasienreël 6.3.10. IF: Structural formula for C4H10 Max. 2/3 INDIEN: Structural formula for C4H10 Max. 2/3 (3) [19] Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 4 DBE/2022 SC/NSC/SS/NSS – Marking Guidelines/Nasienriglyne QUESTION 3/VRAAG 3 3.1 Marking criteria/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 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 Increases/Neem toe  (1) 3.2.2 From A to C:  Increase in molecular mass/size/chain length/surface area/number of C atoms.   Strength of the intermolecular forces increases/More sites for London forces.   More energy is needed to overcome/break intermolecular forces.  OR From C to A:  Decrease in molecular mass/size/chain length/surface area/number of C atoms.   Strength of the intermolecular forces decreases/Less sites for London forces.   Less energy is needed to overcome/break intermolecular forces.  Van A na C:  Verhoging in molekulêre massa/molekulêre grootte/kettinglengte/reaksie- oppervlak/aantal C-atome.   Sterkte van die intermolekulêre kragte verhoog./Meer punte vir Londonkragte.   Meer energie benodig om intermolekulêre kragte te oorkom/breek.  OF Van C na A:  Verlaging in molekulêre massa/molekulêre grootte/kettinglengte/reaksie- oppervlak/aantal C-atome.   Sterkte van die intermolekulêre kragte verlaag./Minder punte vir Londonkragte.   Minder energie benodig om intermolekulêre kragte te oorkom/breek.  (3) 3.3 No / Nee  More than one independent variable./Molar mass and chain length (surface area) are changing.  Meer as een onafhanklike veranderlike./Molêre massa (reaksie-oppervlak) en kettinglengte verander. (2) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 5 DBE/2022 SC/NSC/SS/NSS – Marking Guidelines/Nasienriglyne 3.4 3.4.1 Functional group/homologous series/type of intermolecular forces/type of (1) compound  Funksionele groep/homoloë reeks/soort intermolekulêre kragte/tipe verbinding 3.4.2 Dipole-dipole forces/Dipool-dipoolkragte  (1) 3.5 D / methylbutane / metielbutaan  - Lower boiling point/Weaker intermolecular forces  Laer kookpunt/Swakker intermolekulêre kragte (2) [12] QUESTION 4/VRAAG 4 4.1 4.1.1 Dehydrohalogenation/elimination/dehydrobromination  Dehidrohalogenering/eliminasie/dehidrobrominering (1) 4.1.2 2-methylbut-2-ene / 2-methyl-2-butene  Marking criteria/Nasienkriteria 2-metielbut-2-een / 2-metiel-2-buteen  Methylbutene/metielbuteen  IUPAC name correct/IUPAC-naam korrek  (2) IF/INDIEN Any error, e.g. hyphens omitted and/or incorrect sequence/Enige fout, bv. koppeltekens weggelaat en/of verkeerde volgorde: Max/Maks: 1 2 4.1.3 Water/H2O  (1) 4.1.4 Heat/Hitte  ACCEPT/AANVAAR: (Concentrated) sulphuric acid/catalyst  High temperature/ (Gekonsentreerde) swawelsuur/katalisator Hoë temperatuur (2) 4.1.5 H Marking criteria/Nasienkriteria   Whole structure correct/Hele struktuur O H H H korrek: 2  2 H C C C C H  Only functional group correct:/Slegs funksionele groep korrek: Max/Maks.: 1 2 H H H H IF/INDIEN More than one functional group/Meer as een funksionele groep 0 2 (2) 4.2 4.2.1 Catalyst/Lowers the activation energy./Increases the rate of the reaction.  Katalisator/Verlaag die aktiveringsenergie./Laat reaksietempo toeneem. (1) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 6 DBE/2022 SC/NSC/SS/NSS – Marking Guidelines/Nasienriglyne 4.2.2 The bromine water/Br2/solution decolourises.  Die broomwater/Br2/oplossing ontkleur. OR/OF Bromine water/Br2/solution changes from brown/reddish to colourless. Broomwater/Br2/oplossing verander van bruin/rooi na kleurloos. (1) 4.2.3 Addition/halogenation/bromination  (1) Addisie/halogenering/brominering 4.2.4 C2H6  (3 or/of 0) OR/OF C4H10 OR/OF C6H14 IF structural/condensed formulae: (2 or 0) INDIEN struktuurformules/gekondenseerde formules gebruik: (2 of 0) (3) 4.2.5 Marking criteria Nasienkriteria  Correct functional group i.e. double  Korrekte funksionele groep d.i. bond.  dubbelbinding.   Correct number of C atoms in relation  Korrekte aantal C-atome na to answer in Q4.2.4.  aanleiding van antwoord in V4.2.4.   Whole structure correct.   Hele struktuur korrek.  IF condensed/molecular formulae INDIEN gekondenseerde/molekulêre used: Max. 2⁄3 formules gebruik: Maks. 2⁄3 IF C2H6 in QUESTION 4.2.4/INDIEN C2H6 in VRAAG 4.2.4: H H H H H    H C C C C H OR/OF H C C C C H  H H H H H H H IF C4H10 in QUESTION 4.2.4/ IF C6H14 in QUESTION 4.2.4: INDIEN C4H10 in VRAAG 4.2.4: INDIEN C6H14 in VRAAG 4.2.4: H H H   H H C C C H  H C C H  H H (3) [17] Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 7 DBE/2022 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:  Change in concentration  of products/reactants per (unit) time.   Change in amount/number of moles/volume/mass of products or reactants per (unit) time.  Amount/number of moles/volume/mass of products formed/reactants used per (unit) time.  Rate of change in concentration/amount/number of moles/volume/ mass. (2 or 0) ENIGE EEN:  Verandering in konsentrasie van produkte/reaktanse per (eenheid) tyd.  Verandering in hoeveelheid/getal mol/volume/massa van produkte of reaktanse per (eenheid) tyd.  Hoeveelheid/getal mol/volume/massa van produkte gevorm/reaktanse gebruik per (eenheid) tyd.  Tempo van verandering in konsentrasie/ hoeveelheid/getal mol/ volume/massa. (2 of 0) (2) 5.2  Surface area / state of division / particle size (of MgCO3)   Concentration (of HCℓ)   Reaksieoppervlak/toestand van verdeeldheid/deeltjie-grootte (van MgCO3)  Konsentrasie (van HCℓ) (2) 5.3  At a higher temperature particles move faster/have a higher kinetic energy.   More molecules have enough/sufficient kinetic energy for an effective collision.  OR More molecules have kinetic energy/Ek equal to or greater than the activation energy.  More effective collisions per unit time/second.  OR Frequency of effective collisions increases.  Reaction rate increases.   By 'n hoër temperatuur beweeg die deeltjies vinniger/het die deeltjies hoër kinetiese energie.   Meer molekule het genoeg/voldoende kinetiese energie/Ek vir 'n effektiewe botsing.  OF Meer molekule het kinetiese energie gelyk aan of groter as die aktiveringsenergie.  Meer effektiewe botsings per eenheidtyd/sekonde.  OF Frekwensie van effektiewe botsings verhoog.  Reaksietempo neem toe.  (4) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 8 DBE/2022 SC/NSC/SS/NSS – Marking Guidelines/Nasienriglyne 5.4.1 Marking criteria Nasienkriteria m m  Formula: n =   Formule: n =  M M m m  Substitution of 84 g∙mol-1 in n =   Vervanging van 84 g∙mol-1 in n =   Use mole ratio:  Gebruik molverhouding: n(MgCO3)used = n(CO2)produced  n(MgCO3)gebruik = n(CO2)berei  m m  Substitution of 44 g∙mol-1 in n =  Vervanging van 44 g∙mol-1 in n = or to calculate rate in mol·min-1.  of om tempo te bereken in mol·min-1.   Correct substitution of 0,5 in rate  Korrekte vervanging van 0,5 in equation.  tempovergelyking.   Final answer: 5,238 to 5,28 min   Finale antwoord: 5,238 tot 5,28 min  m n(MgCO3) =  5 = 84  = 0,06 mol(0,0595 mol) n(CO2)produced/gevorm = n(MgCO3)  = 0,06 mol   m Ave rate/gem tempo in mol·min-1: n(CO2) = M 0,5  = 0,0114 mol·min-1 m 44 0,06 = 44  n(CO2 ) m(CO2) = 2,64 g Ave rate/gem tempo = t m(CO2 ) 0,06 Ave rate/gem tempo = 0,0114 = t t 2,64 ∆t = 5, 28 min  0,5 = t ∆t = 5,28 min  (6) 5.4.2 POSITIVE MARKING FROM QUESTION 5.4.1. POSITIEWE NASIEN VANAF VRAAG 5.4.1. Marking criteria Nasienkriteria  Substitution of n(CO2) AND 1,5 dm3 in  Vervanging van n(CO2) EN 1,5 dm3 in V V n= . n= . Vm Vm  Final answer:  Finale antwoord:  \25 to 25,21 dm3·mol-1 25 dm3 tot 25,21 dm3·mol-1  V n= Vm 1,5  0,06  Vm Vm = 25 dm3·mol-1 (25,21 dm3·mol-1) ACCEPT/AANVAAR: 25 dm3 (2) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 9 DBE/2022 SC/NSC/SS/NSS – Marking Guidelines/Nasienriglyne 5.5 Number of CO2 molecules B 1 A Aantal CO2-molekule 2 Kinetic energy/Kinetiese energie Marking criteria/Nasienkriteria Curve B has a higher peak to the left of curve A. 1 Kurwe B het hoër piek aan die linkerkant van kurwe A.  Curve B is below curve A beyond the peak of curve 2 A./Kurwe B is onder kurwe A na die piek van kurwe A.  If BOTH graphs not labelled (A and B): no marks Indien BEIDE grafieke nie benoem nie (A en B): geen punte (2) [18] QUESTION 6/VRAAG 6 6.1.1 2 (mol·dm-3)  (1) 6.1.2 Marking criteria/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. 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) 6.1.3 Cooled/Afgekoel  (1) 6.1.4  A decrease in temperature favours the exothermic reaction./An increase in temperature favours the endothermic reaction.   The forward reaction is favoured./HI concentration increases./Equilibrium (position) shifts to the right.   The forward reaction is exothermic./Reverse reaction is endothermic.   Afname in temperatuur bevoordeel die eksotermiese reaksie./Toename in temperatuur bevoordeel die endotermiese reaksie.   Die voorwaartse reaksie word bevoordeel./ HI-konsentrasie neem toe./Die ewewigs(posisie) skuif na regs.   Voorwaatse reaksie is eksotermies./Die terugwaartse reaksie is endotermies.  (3) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 10 DBE/2022 SC/NSC/SS/NSS – Marking Guidelines/Nasienriglyne 6.2 6.2.1 Products can be converted back to reactants.  OR Both forward and reverse reactions can take place. OR A reaction which can take place in both directions. Produkte kan omgeskakel word na reaktanse.  OF Beide voor-en terugwaartse reaksies kan plaasvind. OF ’n Reaksie wat in beide rigtings kan plaasvind. (1) 6.2.2 Marking criteria Nasienkriteria: a) Δn(N2O4) = n(N2O4)eq – n(N2O4)ini.  (a) Δn(N2O4) = n(N2O4)ewe – n(N2O4)aanv. b) USING ratio: (b) GEBRUIK verhouding: n(NO2) : n(N2O4) = 2 : 1  n(NO2) : n(N2O4) = 2 : 1  c) n(NO2)eq = n(NO2)ini - ∆n(NO2)  (c) n(NO2)ewe = n(NO2)aanv - ∆n(NO2)  d) Divide BOTH by 1 dm3  (d) Deel BEIDE deur 1 dm3  e) Correct Kc expression (formulae in (e) Korrekte Kc uitdrukking (formules in square brackets).  vierkantige hakies).  NO2 N2O4 Initial amount (moles) x 0 Aanvangshoeveelheid (mol) Change in amount (moles) (a) ratio  1,62 0,81  verhouding Verandering in hoeveelheid (mol) Equilibrium amount (moles) (c) Ewewigshoeveelheid (mol) x – 1,62  0,81 Equilibrium concentration (mol∙dm-3) x – 1,62 0,81 Ewewigskonsentrasie (mol∙dm-3) [N2 O 4 ] (e) Wrong or no Kc expression/Verkeerde of geen Kc- Kc   uitdrukking: Max./Maks. [NO2 ] 2 (0,81) 4⁄ = 5 ( x  1,62) 2 (5) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 11 DBE/2022 SC/NSC/SS/NSS – Marking Guidelines/Nasienriglyne 6.2.3 POSITIVE MARKING FROM QUESTION 6.2.2 POSITIEWE NASIEN VAN VRAAG 6.2.2. Marking criteria Nasienkriteria: a) Add 0,79 mol to n(N2O4)ini.  (a) Voeg 0,79 mol by n(N2O4)aanv.  b) USING ratio: n(NO2) : n(N2O4) = 2 : 1 (b) GEBRUIK verhouding: to calculate ∆n(N2O4) as 0,6 mol.  n(NO2) : n(N2O4) = 2 : 1 c) n(NO2)eq = n(NO2)ini + ∆n(NO2) om ∆n(N2O4) as 0,6 mol te bereken.  n(N2O4)eq = n(N2O4)ini - ∆n(N2O4)  (c) n(NO2)ewe = n(NO2)aanv + ∆n(NO2) d) Substitution of concentrations into n(N2O4)ewe = n(N2O4)aanv - ∆n(N2O4)  correct Kc expression.  (d) Vervanging van konsentrasies in e) Equating Kc expresssion from Q6.1.3 korrekte Kc-uitdrukking. and Q6.2.3.  (e) Stel Kc-uitdrukking van Q6.1.3 en f) Final answer: 12,42  Q6.2.3 gelyk aan mekaar.  (Range: 11,27 – 12,42) (f) Finale antwoord: 12,42  (Gebied: 11,27 – 12,42) NO2 N2O4 Initial amount (moles) 0,81 + 0,79  x – 1,62 Aanvangs hoeveelheid (mol) = 1,6 Change in amount (moles) 1,2 0,6  Verandering in hoeveelheid (mol) Equilibrium amount (moles) (c) x – 1,62 +1,2 1 Ewewigshoeveelheid (mol) Equilibrium concentration (mol∙dm-3) x – 0,42 1 Ewewigskonsentrasie (mol∙dm-3) [N2 O 4 ] Wrong Kc expression/Verkeerde Kc- uitdrukking: Kc  [NO2 ] 2 Max./Maks. 4⁄6 (e) (0,81)  1 No Kc expression/Geen Kc- uitdrukking: 6⁄6  (d) ( x  1,62) 2 ( x  0,42) 2 x = 12,42 (mol) (f) (6) [19] QUESTION 7/VRAAG 7 7.1 7.1.1 An acid is a proton (H+ ion) donor.  'n Suur is 'n protondonor/skenker of H+-ioon donor/skenker. (2) 7.1.2 HY  - For the SAME acid concentration: Lower pH / higher H+ or H3O+ concentration / more ionised.  Vir DIESELFDE suurkonsentrasie: Laer pH / hoër H+/H3O+ konsentrasie / meer geïoniseer. (2) 7.1.3 Lower than./Laer as  - Ka < 1 / HX ionises incompletely. / HX has a small Ka value. / HX is a weak acid.  Ka < 1 / HX ioniseer onvolledig. / HX het 'n klein Ka-waarde. / HX is 'n swak suur. (2) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 12 DBE/2022 SC/NSC/SS/NSS – Marking Guidelines/Nasienriglyne 7.2 7.2.1 pH = -log[H3O+] OR/OF [H3O+] = 10-pH  2  = -log[H3O+] [H3O+] = 0,01 mol∙dm-3  (1 x 10-2 mol∙dm-3) (3) 7.2.2 POSITIVE MARKING FROM QUESTION 7.2.1. POSITIEWE NASIEN VAN VRAAG 7.2.1. Marking criteria for OPTION 1: Nasienkriteria vir OPSIE 1:  Substitute c(HCℓ)excess and 0,35 dm 3  Vervang c(HCℓ)oormaat en 0,35 dm3 om to calculate n(HCℓ)excess. n(HCℓ)oormaat te bereken.  Substitute to calculate n(HCℓ)initial   Vervang om n(HCℓ)aanv te bereken.   n(HCℓ)react = n(HCℓ)ini – n(HCℓ)excess.  n(HCℓ)rea = n(HCℓ)aanv – (HCℓ)oormaat  Use ratio:  Gebruik verhouding: n(NaOH) = n(HCℓ)  n(NaOH) = n(HCℓ)  n n  Substitute 0,15 dm3 in c = .   Vervang 0,15 dm3 in c = .  V  Final answer: 0,02 mol∙dm-3   Finale antwoord: 0,02 mol∙dm-3  or 0,0167 mol∙dm-3 or 0,017 mol∙dm-3 of 0,0167 mol∙dm-3 of 0,017 mol∙dm-3 OPTION 1/OPSIE 1 n(HCℓ)excess/oormaat = cV = 0,01 x 0,35  = 3,5 x 10-3 mol n(HCℓ)initial/aanv = cV = 0,03 x 0,2  = 0,006 mol n(HCℓ)reacted/reageer = 0,006 – 3,5 x 10-3  = 0,0025 mol n(NaOH)reacted/reageer = n(HCℓ)reacted/reageer = 0,0025 mol  n c(NaOH) = V 0,0025 = 0,15  = 0,02 mol∙dm-3  (0,0167 mol∙dm-3 or/of 0,017 mol∙dm-3) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 13 DBE/2022 SC/NSC/SS/NSS – Marking Guidelines/Nasienriglyne OPTION 2/OPSIE 2 Marking criteria Concentration ratio in final solution:  Ratio HCℓ : H3O+ = 1 : 1  Konsentrasie verhouding in finale  c(HCℓ)excess = 0,01 (mol·dm-3)  oplossing:  n(HCℓ)react = n(HCℓ)ini –(HCℓ)excess. HCℓ : H3O+ = 1 : 1   Use ratio: n(NaOH) = n(HCℓ)  Thus/dus [HCℓ] = 0,01 mol·dm-3   Final answer: 0,02 mol∙dm-3  Nasienkriteria [HCℓ]react = [HCℓ]initial - [HCℓ]excess  Verhouding HCℓ : H3O+ = 1 : 1   c(HCℓ)oormaat = 0,01 (mol·dm-3)  = 0,03 – 0,01   n(HCℓ)reag = n(HCℓ)aanv –(HCℓ)oormaat. = 0,02 mol·dm-3  Gebruik verhouding: n(NaOH) = n(HCℓ)  Concentration ratio in final solution:  Finale antwoord: 0,02 mol∙dm-3  Konsentrasie verhouding in oorspronklike oplossing: HCℓ : NaOH = 1 : 1  [NaOH] = 0,02 mol·dm-3  OPTION 3/OPSIE 3 Marking criteria c n c1 1 n1  Substitute 350 cm3 in c1 1 = n1  = 2 2 2 c2 2 n2  Ratio of HCℓ : H3O+ = 1 : 1  c1 (200) 1  n(HCℓ)react = n(HCℓ)ini –(HCℓ)excess. =   Use ratio: n(NaOH) = n(HCℓ)  (0,01)(350)  1 c n  Substitute 150 cm3 in c1 1 = n1  c1 = 0,0175 mol·dm-3 2 2 2  Final answer: 0,02 mol∙dm-3  or 0,0167 mol∙dm-3 c(HCℓ)react = c(HCℓ)ini – c(HCℓ)excess or 0,017 mol∙dm-3 = 0,03 – 0,0175  Nasienkriteria = 0,0125 mol·dm-3 c V n  Vervang 350 cm3 in c1 V1 = n1  ca a na 2 2 2 =  Verhouding HCℓ : H3O+ = 1 : 1  cb b nb  n(HCℓ)reag = n(HCℓ)aanv –(HCℓ)oormaat.  Gebruik verhouding: (0,0125)(200) 1 n(NaOH) = n(HCℓ)  =  cb (150) 1 c V n  Vervang 150 cm3 in 1 1 = 1  c2 V2 n2 c(NaOH) = 0,0167 mol·dm  -3  Finale antwoord: 0,02 mol∙dm-3  of 0,0167 mol∙dm-3 of 0,017 mol∙dm-3 (0,0167 mol∙dm-3 or/of 0,017 mol∙dm-3) (7) [16] Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 14 DBE/2022 SC/NSC/SS/NSS – Marking Guidelines/Nasienriglyne QUESTION 8/VRAAG 8 8.1 8.1.1 Temperature/Temperatuur: 25 °C/298 K  Pressure/Druk: 101,3 kPa/1 atmosphere  Concentration/Konsentrasie: 1 mol·dm-3  (3) 8.1.2 OPTION 1/OPSIE 1 Notes/Aantekeninge  E cell   Ereduction   E oxidation   Accept any other correct formula from the  data sheet./Aanvaar enige ander korrekte 2,89 = Ereduction – (-1,66)  formule vanaf gegewensblad.  Ereduction = 1,23 (V)   Any other formula using unconventional abbreviations, e.g. E°cell = E°OA - E°RA followed by correct substitutions:/Enige ander formule X is O2/oxygen/suurstof  wat onkonvensionele afkortings gebruik bv. E°sel = E°OM - E°RM gevolg deur korrekte [X marked independently/ vervangings: 4 X onafhanklik nagesien] 5 OPTION 2/OPSIE 2 O2(g) + 4H+ + 4e  2H2O E  = +1,23 V   Aℓ(s) → Aℓ3+(aq) + 3e- E  = +1,66 V  4Aℓ(s) + 3O2(g) + 12H+  4Aℓ3+(aq) + 6H2O E  = +2,89 (V)  X is O2/oxygen/suurstof  [X marked independently/X onafhanklik nagesien] (5) 8.1.3 Aℓ  (1) 8.1.4 O2(g) + 4H+ + 4e → 2H2O  Ignore phases./Ignoreer fases. Marking criteria/Nasienkriteria:  2H2O ← O2(g) + 4H+ + 4e (2 ) O2(g) + 4H+ + 4e ⇌ 2H2O (1 ) 2 2  0  0 + O2(g) + 4H + 4e ← 2H2O ( ) 2H2O ⇌ O2(g) + 4H + 4e + ( ) 2 2  Ignore if charge omitted on electron./Ignoreer indien lading weggelaat op elektron.  If charge (+) omitted on H+/ Indien lading (+) weggelaat op H+: Max./Maks: 1 2  Example/Voorbeeld: O2(g) + 4H + 4e → 2H2O  (2)  8.1.5 Aℓ (s) | Aℓ3+(aq) || O2(g) | H+(aq) | H2O(ℓ) | Pt(s)   OR/OF Aℓ (s) | Aℓ3+(aq) || O2(g) | H+(aq) | H2O(ℓ) | C(s) OR/OF Aℓ | Aℓ3+ || O2 | H+ | H2O | Pt (3) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

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Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 16 DBE/2022 SC/NSC/SS/NSS – Marking Guidelines/Nasienriglyne 8.2 Copper/Koper   Cu is a weaker reducing agent than Ni and will not reduce Ni2+ (to Ni). / Cu will not be oxidised (to Cu2+).  Zn is a stronger reducing agent than Ni and will reduce Ni2+ (to Ni). / Zn will be oxidised (to Zn2+).  Cu is 'n swakker reduseermiddel as Ni en sal nie Ni2+ (na Ni) reduseer nie. / Cu sal nie geoksideer word nie na (Cu2+).  Zn is 'n sterker reduseermiddel as Ni en sal Ni2+ (na Ni) reduseer. / Zn sal geoksideer word (na Zn2+). NOTE/LET WEL: The mark for 'reduce' can be awarded at any ONE of the two comparisons. Die punt vir 'reduseer' kan toegeken word by ENIGEEN van die twee vergelykings. (4) [18] QUESTION 9/VRAAG 9 9.1 Marking criteria/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. ANY ONE/ENIGE EEN:  The chemical process in which electrical energy is converted to chemical energy.   The use of electrical energy to produce a chemical change.  Decomposition of an ionic compound by means of electrical energy.  The process during which an electric current passes through a solution/ionic liquid/molten ionic compound.  Die chemiese proses waarin elektriese energie omgeskakel word na chemiese energie.   Die gebruik van elektriese energie om 'n chemiese verandering te weeg te bring.  Ontbinding van 'n ioniese verbinding met behulp van elektriese energie.  Die proses waardeur 'n elektriese stroom deur 'n oplossing/ioniese vloeistof/gesmelte ioniese verbinding beweeg. (2) 9.2 9.2.1 X (1) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 17 DBE/2022 SC/NSC/SS/NSS – Marking Guidelines/Nasienriglyne 9.2.2 2H2O(ℓ) + 2e-  H2(g) + 2OH─(aq)  Ignore phases/Ignoreer fases Marking criteria/Nasienkriteria:  H2(g) + 2OH─(aq) ← 2H2O(ℓ) + 2e- ( 2 ) 2H2O(ℓ) + 2e- ⇌ H2(g) + 2OH─(aq) ( 1 ) 2 2 ─ 0 ─ 0 H2(g) + 2OH (aq) ⇌ 2H2O(ℓ) + 2e ( - - ) 2H2O(ℓ) + 2e ← H2(g) + 2OH (aq) ( ) 2 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) 9.2.3 X to/na Y  (1) 9.2.4 2H2O(ℓ) + 2Cℓ─(aq)  → Cℓ2(g) + H2(g) + 2OH─(aq)  Bal  OR/OF 2H2O(ℓ) + 2NaCℓ(aq) → Cℓ2(g) + H2(g) + 2NaOH(aq) Ignore phases/Ignoreer fases Marking criteria/Nasienkriteria:  Reactants  Products  Balancing:  Reaktanse Produkte Balansering  Ignore double arrows./Ignoreer dubbelpyle.  Marking rule 6.3.10/Nasienreël 6.3.10. (3) 9.3 Increases / Toeneem  (1) 9.4 Solution becomes basic / alkaline OR NaOH / OH─ (ions) form  Oplossing word basies / alkalies OF NaOH / OH─(-ione) vorm (1) [11] TOTAL/TOTAAL: 150 Copyright reserved/Kopiereg voorbehou