Physical Sciences Grade 12 Paper 2 NSC June 2023 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) 2023 MARKING GUIDELINES/NASIENRIGLYNE MARKS/PUNTE: 150 These marking guidelines consist of 20 pages. Hierdie nasienriglyne bestaan uit 20 bladsye. Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 2 DBE/2023 SC/NSC/SS/NSS – Marking Guidelines/Nasienriglyne QUESTION/VRAAG 1 1.1 A  (2) 1.2 D  (2) 1.3 B  (2) 1.4 C  (2) 1.5 C  (2) 1.6 B  (2) 1.7 C  (2) 1.8 D  (2) 1.9 A  (2) 1.10 D  (2) [20] QUESTION/VRAAG 2 2.1 Compounds with one or more multiple bonds between C atoms in the hydrocarbon chain.  (2 or 0) Verbindings met een of meer meervoudige bindings tussen C-atome in die koolwaterstofkettings. (2 of 0) OR/OF A hydrocarbon with two or more bonds between the C-atoms. ‘n Koolwaterstof met twee of meer bindings tussen die C-atome. OR/OF Hydrocarbons containing not only single bonds between C atoms. Koolwaterstowwe wat nie slegs enkelbindings tussen die C-atome bevat nie. ACCEPT/AANVAAR: Compounds with one or more double/triple bonds between C atoms in the hydrocarbon chain. Verbindings met een of meer dubbel/trippelbindings tussen C-atome in die koolwaterstofkettings. (2) 2.2.1 D (1) Copyright reserved/Kopiereg voorbehou

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 3 DBE/2023 SC/NSC/SS/NSS – Marking Guidelines/Nasienriglyne 2.2.2 2,4-dimethylhexane  2,4-dimetielheksaan Marking criteria:  Correct stem i.e. hexane.   Substituents (dimethyl) correctly identified.   IUPAC name completely correct including numbering, sequence, hyphens and commas.  Nasienkriteria:  Korrekte stam d.i. heksaan.   Substituente (dimetiel) korrek geïdentifiseer.   IUPAC-naam heeltemal korrek insluitende nommering, volgorde, koppeltekens en kommas.  (3) 2.2.3 Propan-2-ol /2-propanol  Marking criteria:  Correct stem i.e. propanol.   IUPAC name completely correct including numbering and hyphens.  Nasienkriteria:  Korrekte stam d.i. propanol.   IUPAC-naam heeltemal korrek insluitende nommering en koppeltekens.  (2) 2.2.4 hept-1-ene/1-heptene  hept-1-een/1-hepteen Marking criteria:  Correct stem i.e. heptene.   IUPAC name completely correct including numbering and hyphens.  Nasienkriteria:  Korrekte stam d.i. hepteen.   IUPAC-naam heeltemal korrek insluitende nommering en koppeltekens.  (2) 2.2.5 Marking criteria/Nasienkriteria  Correct molecular formula: C8H18  Korrekte molekulêre formula: C8H18  Correct molecular formula of inorganic reactant and products.  Korrekte molekulêre formule vir die anorganiese reaktant en produkte.  Balancing/Balansering  2C8H18  + 25O2 → 16CO2 + 18H2O Bal  Notes/Aantekeninge:  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 struktuurformules gebruik: Max/Maks. 2 3 (3) 2.3.1 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. Compounds with the same molecular formula but different functional groups/homologous series.  Verbindings met dieselfde molekulêre formule maar verskillende funksionele groepe/homoloë reekse. (2) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 4 DBE/2023 SC/NSC/SS/NSS – Marking Guidelines/Nasienriglyne 2.3.2 Marking criteria/Nasienkriteria:  Functional group for aldehyde correct   Functional group for ketone correct  Funksionele groep van aldehied korrek Funksionele groep van ketoon korrek  Whole structure of aldehyde correct   Whole structure of ketone correct  Hele struktuur van aldehied korrek Hele struktuur van ketoon korrek O H  H H H H H   H C C C C O H C C C C H H H H H H H H (4) 2.4 Marking criteria  Calculate the mass/percentage of oxygen.   Substitute correct mass and molar mass for both C and H into n = .   Substitute correct mass and molar mass for O into n = .   Simplify ratio. (Accept correct empirical formula if no ratio is given.)   Correct molecular formula.  Nasienkriteria:  Bereken die massa/persentasie suurstof.  m  Vervang korrekte massa en molêre massa vir beide C en H in n = .  m  Vervang korrekte massa en molêre massa vir O in n = .   Vereenvoudig verhouding. (Aanvaar korrekte empiriese formule indien geen verhouding nie )   Korrekte molekulêre formule.  OPTION 1/OPSIE 1 C H O Mass / Massa 1,09 0,18 2 – (1,09 + 0,18)  = 0,73 n= n= n= Moles /mol = =  =  = 0,0908 = 0,18 = 0,046 Simplest ratio Eenvoudigste 2 4 1  verhouding Empirical formula C2H4O Empiriese formule M(C2H4O) x n= 88 (g·mol-1) 44n = 88 n=2 Molecular formula of compound X/ Molekulêre formule van verbinding X: C4H8O2  Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 5 DBE/2023 SC/NSC/SS/NSS – Marking Guidelines/Nasienriglyne OPTION 2/OPTION 2 C H O Percentage/Persentasie 54,5 9 36,5  Moles /mol   Simplest ratio  Eenvoudigste 2 4 1 verhouding Empirical formula C2H4O Empiriese formule M(C2H4O) x n= 88 (g·mol-1) 44n = 88 n=2 Molecular formula of compound X/ Molekulêre formule van verbinding X: C4H8O2  (6) [25] Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 6 DBE/2023 SC/NSC/SS/NSS – Marking Guidelines/Nasienriglyne QUESTION/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 compound) equals atmospheric pressure.  Die temperatuur waarby die dampdruk (van 'n verbinding) gelyk is aan die atmosferiese druk. (2) 3.2 Marking criteria/Nasienkriteria  Compare compounds in terms of branches/chain lengths/surface area.  Vergelyk verbindings in terme van vertakkings/kettinglengte/oppervlakarea.  Co pare stre gths of I F’s/Vergelyk sterkte van IMK'e.  Compare energy/Vergelyk energie  Butan-1-ol   Has a longer chain length./is less branched./has a larger surface area/ contact area.   Strength of the intermolecular forces is greater./There are more sites for London forces.   More energy is needed to overcome/break intermolecular forces.   Het 'n langer kettinglengte./is minder vertak./het 'n groter kontakoppervlak/reaksieoppervlak.   Sterkte van die intermolekulêre kragte verhoog./Daar is meer plekke vir Londonkragte.   Meer energie word benodig om die intermolekulêre kragte te oorkom/breek.  OR/OF  2-methylpropan-1-ol has a shorter chain length./is more branched./ has a smaller surface area/contact area.  Strength of the intermolecular forces is weaker./There are fewer sites for London forces.  Lesser energy is needed to overcome/break intermolecular forces.  2-metielpropan-1-ol het 'n korter kettinglengte./is meer vertak./het 'n kleiner kontakoppervlak/reaksieoppervlak.  Sterkte van die intermolekulêre kragte is swakker./Daar is minder plekke vir Londonkragte.  Minder energie word benodig om intermolekulêre kragte te oorkom/breek. (4) 3.3 Boiling point/Kookpunt  (1) 3.4 3.4.1 S (1) 3.4.2 P (1) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 7 DBE/2023 SC/NSC/SS/NSS – Marking Guidelines/Nasienriglyne 3.4.3 R (1) 3.5 Propanoic acid/P has the strongest intermolecular forces.  OR Two sites for hydrogen bonding (which is stronger than other intermolecular forces). OR Most energy needed to separate the chains. Propanoësuur/P het die sterkste intermolekulêre kragte. OF Twee plekke vir waterstofbindings (wat sterker is as die ander intermolekulêre kragte). OF Meeste energie benodig om kettings te skei. (1) [11] QUESTION/VRAAG 4 4.1 4.1.1 Halogenation/Bromination  Halogenering/Brominering (1) 4.1.2 The bromine water/Br2/solution decolourises./Brown colour disappears.  Die broomwater/Br2/oplossing ontkleur./Bruin kleur verdwyn. OR/OF Bromine water/Br2/solution changes from brown/reddish to colourless. Broomwater/Br2/oplossing verander van bruin/rooierig na kleurloos. (1) 4.1.3 H Marking criteria/Nasienkriteria  Functional group correct  H C H Funksionele groep korrek H H  Whole structure correct   Hele struktuur korrek H C C C H H (2) 4.1.4 2-chloro-2-methylpropane /2-chloro-2-metielpropaan ACCEPT/AANVAAR: 2-chloromethylpropane / 2-chlorometielpropaan (2) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 8 DBE/2023 SC/NSC/SS/NSS – Marking Guidelines/Nasienriglyne 4.1.5 Marking criteria:  Cℓ ato o seco d C ato o co pou d R   Whole structure of compound R correct   React compound R with NaOH(aq)/ KOH(aq)/LiOH(aq) OR H2O   OH-group replaces Cℓ ato at the same position.   Whole structure of alcohol correct.   NaCℓ(aq)/KCℓ(aq)/LiCℓ(aq) OR HCℓ(aq)  (must correspond to the inorganic reactant used) Nasienkriteria:  Cℓ-atoom op tweede C-atoom van verbinding R   Hele struktuur van verbinding R korrek   Reageer verbinding R met NaOH(aq)/ KOH(aq)/LiOH(aq) OF H2O   OH-groep vervang Cℓ-atoom by dieselfde posisie.   Hele struktuur van alkohol korrek.   NaCℓ(aq)/KCℓ(aq)/LiCℓ(aq) OF HCℓ(aq)  (moet ooreenstem met die anorganiese reaktans gebruik) H H H C H H C H H H H H   H C C C H + NaOH(aq)/ H C C C H + NaCℓ(aq)/ KOH(aq)/ H KCℓ(aq)/ H Cℓ LiOH(aq)/ H O H OR/OF LiCℓ(aq)/  OR/OF  H2O H HCℓ Notes/Aantekeninge:  Ignore/Ignoreer ⇌  Accept all inorganic reagents as condensed./Aanvaar alle anorganiese reagense as gekondenseerd.  Accept coefficients that are multiples. Aanvaar koëffisiënte wat veelvoude is.  Any additional reactants and/or products Enige addisionele reaktanse en/of produkte: Max./Maks. ⁄  Incorrect balancing/Verkeerde balansering: Max./Maks. ⁄  Molecular formulae/Molekulêre formule: Max./Maks. ⁄  Condensed formulae/Gekondenseerde formule: Max./Maks. ⁄ Accept/Aanvaar: -OH as condensed / -OH as gekondenseerd Condensed formulae/Gekondenseerde formule:   CH3C(CH3)CℓCH3  + NaOH(aq)/ CH3C(CH3)OHCH3  + NaCℓ(aq)/ KOH(aq)/ KCℓ(aq)/ LiOH(aq)/ LiCℓ(aq)/ OR/OF OR/OF H2O HCℓ (6) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 9 DBE/2023 SC/NSC/SS/NSS – Marking Guidelines/Nasienriglyne 4.1.6 2-methylpropan-2-ol/2-methyl-2-propanol 2-metielpropan-2-ol/2-metiel-2-propanol ACCEPT/AANVAAR: Methylpropan-2-ol/ Metielpropan-2-ol (2) 4.1.7 Dehydration/Dehidrasie/Dehidratering  (1) 4.2.1 Esterfication/Condensation  Verestering/Esterfikasie/Kondensasie (1) 4.2.2 Butylpropanoate  Butielpropanoaat (2) [18] QUESTION/VRAAG 5 5.1 Initial concentration is 0 (of NO2)./Concentration increases./ Curve starts at 0.  Beginkonsentrasie is 0 (van NO2)./Konsentrasie verhoog./Kurwe begin by 0. OR/OF Curve B has an initial concentration and is the reactant as its concentration decreases. Kurwe B het 'n beginkonsentrasie en is die reaktant aangesien sy konsentrasie afneem. (1) 5.2 True/Waar  n mol of N2O5 forms 2n mol of NO2 per unit time.  n mol N2O5 vorm 2n mol NO2 per eenheidstyd. OR/OF Gradient of graph for NO2 is twice the gradient of graph for N2O5. Gradiënt van grafiek vir NO2 is twee keer die gradiënt van grafiek vir N2O5. NOTE/LET WEL: If gradients calculated correctly award mark. Indien gradiënte korrek bereken word punt toegeken. (2) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 10 DBE/2023 SC/NSC/SS/NSS – Marking Guidelines/Nasienriglyne 5.3.1 Marking criteria/Nasienkriteria:  Formula: c = / n(NO2) = cV / n(NO2) =   Substitute change in concentration.  Vervang verandering in konsentrasie .  Substitute M (46) and V (2)./Vervang M (46) en V (2).   Final correct answer/ Finale korrekte antwoord: 1,84 g  OPTION 1/OPSIE 1 OPTION 2/OPSIE 2 n(NO2) = cV c(NO2) =  = (200 x 10-4)x 2  either/ 200 x 10-4 = enige = 4 x 10-2 mol ) ) een  both/ m = 1,84 g  beide n(NO2) = 4 x 10-2 = m = 1,84 g  (4) 5.3.2 Marking criteria/Nasienkriteria:  Substitute the change in concentration into rate formula.  Vervang verandering in konsentrasie in tempo formule.  Substitute time into the rate formula./ Vervang tyd in tempo formule.   Use mol ratio/Gebruik molverhouding: rate/tempo(O2) = ½ rate/tempo(N2O5)/ rate/tempo(O2) = ¼ rate/tempo(NO2)   Final correct answer/Finale korrekte antwoord: 1 x 10-5 (mol·dm-3·s-1)  NOTE/LET WEL If concentration is converted to moles, final moles per s (mol·s-1) must be converted back to concentration (mol·dm-3·s-1). i.e. there must be multiplication and division by 2. If one of these is omitted: Max. ⁄ Indien konsentrasie omgeskakel is na mol, moet die finale mol per s (mol·s-1) omgeskakel word na konsentrasie (mol·dm-3·s-1) d.w.s daar moet vermenigvuldig en gedeel word deur 2. Indien een van hierdie uitgelaat word: Maks. ⁄ OPTION 1/OPSIE 1 c ) Ave rate/gem tempo = - t - - ( - ) =- - ) = 2 x 10 (mol·dm-3·s-1) -5 rate(O2) = ½ rate(N2O5) = ½(2 x 10-5 )  = 1 x 10-5 (mol·dm-3·s-1)  OPTION 2/OPSIE 2 c ) Ave rate/gem tempo = t - ( - )) = - ) = 4 x 10 (mol·dm-3·s-1) -5 rate(O2) = ¼ rate(NO2) = ¼(4 x 10-5 )  = 1 x 10-5 (mol·dm-3·s-1)  Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 11 DBE/2023 SC/NSC/SS/NSS – Marking Guidelines/Nasienriglyne OPTION 3/OPSIE 3 ∆c 2) ½ ∆c 2O5) OR/OF ∆c 2) ¼∆c 2) = ½ (60 x 10-4 – 200 x 10-4)  = ¼(280 x 10-4 (– 0) ) = ½ (140 x 10-4) = 7 x 10-3 mol·dm-3 = 7 x 10-3 mol·dm-3 = 7 x 10-3 mol·dm-3 c ) Ave rate/gem tempo = t ) - ( = - ) = 1 x 10-5 (mol·dm-3·s-1)  (4) 5.4 5.4.1 Marking criteria/Nasienkriteria Number of particles Q  Curve Q must be above the given curve P and have the same shape as the given curve P and the peaks have to correspond.  P Kurwe Q moet bo die gegewe kurwe P wees en moet dieselfde vorm hê as die gegewe kurwe P en die maksimums moet ooreenstem Kinetic energy  Starts at origin and not crossing curve P.  Begin by oorsprong en nie kruis met kurwe P nie. (2) 5.4.2 Higher than/Hoër as   When the concentration of N2O5 is higher there are more N2O5 particles per unit volume.   More effective collisions per unit time/second.  OR Higher frequency of effective collisions.  'n Hoër konsentrasie van N2O5 bevat meer N2O5-deeltjies per eenheidsvolume.   Meer effektiewe botsings per eenheidstyd/sekonde.  OF Hoër frekwensie van effektiewe botsings. (3) [16] Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 12 DBE/2023 SC/NSC/SS/NSS – Marking Guidelines/Nasienriglyne QUESTION/VRAAG 6 6.1 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. 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 6.2.1 n[H2(g)] = 0,11 (mol)  (1) 6.2.2 OPTION 1/OPSIE 1 OPTION 2/OPSIE 2 n(HI)used/gebruik = 2n(I2) H = 2(0,11) Kc = H n(HI)eq = 1 - 0,22 = 0,78 (mol)  0,02 = H HI ol∙d -3 n(HI) = 0,78 (mol)  (1) 6.3 6.3.1 Endothermic/Endotermies  (1) 6.3.2 Kc increased:  The concentration of the product/H2(g) and I2(g) is increased.  OR: The concentration of the reactant/HI decreases.  The increase in temperature favoures the forward reaction.   (According to Le Chatelier's principle) an increase in temperature favours the endothermic reaction.  Kc het verhoog:  Die konsentrasie van die produkte/H2(g) en I2(g) verhoog.  OF: Die konsentrasie van die reaktanse/HI verlaag.  'n Toename in temperatuur bevoordeel die voorwaartse reaksie.   (Volgens Le Chatelier se beginsel) sal 'n toename in temperatuur die endotermiese reaksie bevoordeel.  (3) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 13 DBE/2023 SC/NSC/SS/NSS – Marking Guidelines/Nasienriglyne 6.3.3 POSITIVE MARKING FROM Q6.2/POSITIEWE NASIEN VANAF V6.2 Marking criteria: Nasienkriteria: (a) Correct Kc expression (formulae in (a) Korrekte Kc uitdrukking (formules in square brackets).  vierkantige hakies).  (b) Substitution of 0,09 in Kc expression.  (b) Vervang 0,09 in Kc uitdrukking.  (c) Correct initial moles from 6.2.1 and (c) Aanvanklike mol korrek vanaf 6.2.1 6.2.2.  en 6.2.2.  (d) USING ratio: nHI(g) : 2nI2(g) = 1:2  (d) GEBRUIK verhouding: (e) Substitution of concentrations into nHI(g) : 2nI2(g) = 1:2  correct Kc expression.  (e) Vervang konsentrasies in korrekte (f) Subtraction [HI]ini – [HI]  Kc uitdrukking.  (g) Substitution of 128 in m = nM.  (f) Verskil: [HI]aanv – Δ[HI]  (h) Final answer: 80,64 g  (g) Vervang 128 in m = nM.  (range: 79,36 - 80,64 g) (h) Finale antwoord: 80,64 g  (gebied: 79,36 - 80,64 g) OPTION 1/OPSIE 1 H I Kc =  (a) HI  (c) ( 0,11 and/en 0,78 from 6.2.1 and/en 6.2.2) (b)  ) )  (e) 0,09 = - ) (d) x = 0,0775 [HI] equilibrium/ewewig = [HI]ini/aanv – [HI] = 0,78 – 2(0,0775) (f) = 0,63 ol∙d -3 (0,625) n(HI) = cV = (0,63)(1) OR/OF = 0,63 mol (0,625) m(HI) = cVM = (0,63)(1)(128)  (g) m(HI) = nM = 80,64 g  (h) (g) = (0,63)(128)  = 80,64 g  (h) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 14 DBE/2023 SC/NSC/SS/NSS – Marking Guidelines/Nasienriglyne OPTION 2/OPSIE 2 HI I2 H2 Initial quantity (mol) 0,78 0,11 0,11 Aanvanklike hoeveelheid (mol) Change (mol) Ratio 1:2 2x x x  Verandering (mol) Quantity at equilibrium (mol) 0,78 - 2x 0,11 + x 0,11 + x Hoeveelheid by ewewig (mol) Equilibrium concentration Ewewigskonsentrasie ol∙d -3) H I Kc =  (a) (b) HI 09 = ) ) 0, (e) - ) x = 0,0775 (f) [HI] equilibrium/ewewig = 0,78 – 2(0,0775)  = 0,63 ol∙d -3 (0,625) n(HI) = cV = (0,63)(1) OR/OF = 0,63 mol (0,625 mol) m(HI) = cVM = (0,63)(1)(128)  (g) m(HI) = nM = 80,64 g  (h) = (0,63)(128)  (g) = 80,64 g (h) (8) [16] QUESTION/VRAAG 7 7.1 7.1.1 ANY ONE:  A substance whose aqueous solution contains ions.  (2 or 0)  Substance that dissolves in water to give a solution that conducts electricity.  A substance that forms ions in water/forms ions when molten. ENIGE EEN:  'n Stof waarvan die oplossing ione bevat.  (2 of 0)  'n Stof wat in water oplos om 'n oplossing te vorm wat elektrisiteit gelei.  'n Stof wat ione vorm in water/ione vorm wanneer gesmelt. (2) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 15 DBE/2023 SC/NSC/SS/NSS – Marking Guidelines/Nasienriglyne 7.1.2 A H2SO4 is diprotic./Donates more than one mole of H+ ions per mole of acid  (and both acids are of the same concentration)./H2SO4 has a higher Ka value. H2SO4 is diproties./Skenk meer as een mol H+ ione per mol suur (en beide sure het dieselfde konsentrasie)/ H2SO4 het 'n hoër Ka-waarde. OR/OF It ionises to produce more than one mole of protons/H+ ions for each mole of H2SO4./H2SO4 has a higher Ka value. Dit ioniseer om meer as een mol protone/ H+-ione vir elke mol H2SO4 te vorm./H2SO4 het 'n hoër Ka-waarde. (2) 7.1.3 B Stronger acid/ionises completely (and both acids are of the same concentration)./HNO3 has a higher Ka value. Sterker suur/ioniseer volledig (en beide sure het dieselfde konsentrasie)./ HNO3 het 'n hoër Ka-waarde. OR/OF C/CH3COOH is a weaker acid/ionises incompletely. C/CH3COOH is 'n swak suur/ioniseer onvolledig. (2) 7.2 7.2.1 Marking criteria/Nasienkriteria:  Substitute/Vervang 0,04 ol∙d -3 and 25 x 10-3 dm3 (25 cm3) and 19,5 x 10-3 dm3 (19,5 cm3).   USE mol ratio:/GEBRUIK molverhouding: n(Na2CO3) : n(HCℓ) = 1 : 2   Final answer/Finale antwoord: 0,10 to/tot 0,103 mol·dm-3  OPTION 1/OPSIE 1 OPTION 2/OPSIE 2 ca a n(Na2CO3) = cV c = 0,04 x 0,025 = 0,001 mol ca )  n(HCℓ) = 2n(Na2CO3)  =  = 0,002 mol  ) ) ca = 0,10 mol·dm-3  (0,103) [HCℓ] = = = 0,10 mol∙dm-3  (0,103) (3) 7.2.2 Greater than/Groter as  - The few drops of water will dilute the HCℓ, therefore greater volume of acid will be needed to neutralise the base. 'n Paar druppels water sal die HCℓ verdun, daarom sal 'n groter volume suur benodig word om die basis te neutraliseer. (2) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 16 DBE/2023 SC/NSC/SS/NSS – Marking Guidelines/Nasienriglyne 7.2.3 POSITIVE MARKING FROM Q7.2.1/POSITIEWE NASIEN VANAF V7.2.1 Marking criteria: Nasienkriteria: (a) Substitute 0,1 ol∙d -3 & (a) Vervang 0,1 mol∙dm-3 & 18,7 x 10-3 dm3 18,7 x 10-3 dm3 (18,7 cm3).  (18,7 cm3). (b) Use mole ratio: 1:1  (b) Gebruik molverhouding: 1:1  (c) Calculate n(NH3) / m(NH3) in (c)Bereken n(NH3) / m(NH3) in 250 cm3: 3 3 250 cm : Substitute 0,25 dm Vervang 0,25 dm3 (250 cm3).  (250 cm )  3 (d) Vervang 0,022 dm3 (22 cm3).  (d) Substitute 0,022 dm (22 cm ).  3 3 (e) Vervang 0,02 dm3 (20 cm3) om 3 3 (e) Substitute 0,02 dm (20 cm ) to mol/massa van oorspronklike calculate mole/mass in initial solution. oplossing te bereken.  (f) Use 17 g·mol-1 in n = . (f) Gebruik 17 g·mol-1 in n = . (g) Final answer: 18,06 g  (g) Finale antwoord: 18,06 g  Range: 17 to 19,13 g Gebied: 17 tot 19,13 g OPTION 1/OPSIE 1 OPTION 2/OPSIE 2 HCℓ) c HCℓ) c = (0,1)(18,7 x 10-3)  (a) = (0,1)(18,7 x 10-3)  (a) -3 -3 = 1,87 x 10 mol = 1,87 x 10 mol n(NH3)reacted/reageer HCℓ)reacted/reageer (NH3)reacted/reageer HCℓ)reacted/reageer -3 = 1,87 x 10 mol  (b) = 1,87 x 10-3 mol (b) n(NH3) in 22 cm3 = 1,87 x 10-3 mol n(NH3) in 22 cm3 = 1,87 x 10-3 mol (c) -  n= ) ) n(NH3) in 250 cm3 = (d) 1,87 x 10-3 = = 0,021 mol  (f) m(NH3) = 3,72 x 10-3 g in 22 cm3 (2,13 x 10-2) (c) -  n(NH3) in initial 20 cm3 = 0,021 mol ) ) m(NH3) in 250 cm3 =  (d) = 0,361 g n= m(NH3) in initial 20 cm3 = 0,361 g 0,021 =  (f) ) ) m(NH3) in 1 000 cm3 = m(NH3) = 0,357 g in 20 cm3 (e) = 18,06 g(g) ) ) m(NH3) =  (e) = 17,85 g(g) (18,06) (7) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 17 DBE/2023 SC/NSC/SS/NSS – Marking Guidelines/Nasienriglyne OPTION 3/OPSIE 3 OPTION 4/OPSIE 4 c HCℓ) c ca a = (0,1)(18,7 x 10-3)  (a) a -3 c ) (d) = 1,87 x 10 mol =  (b) ) ) (NH3)reacted/reageerHCℓ)reacted/reageer (a) = 1,87 x 10-3 mol (b) c1 = 0,085 mol·dm-3 n(NH3) in 22 cm3 = 1,87 x 10-3 mol [NH3] in 22 cm3 = 0,085 mol·dm-3 [NH3] in 250 cm3 = 0,085 mol·dm-3  (c) - ) ) n(NH3) in 250 cm3 = c1V1 = c2V2 (d) c1(0,02)  = (0,085)(0,25)  (c) = 0,021 mol (e) c1 = 1,06 mol·dm-3 c( c ) c( d ) m = cVM (f) = (1,06)(1)(17) = 18,06 g  (g) n(NH3) in 1 000 cm3 =  (e) = 1,06 mol n= 1,06 = (f) m(NH3) = 18,06 g  (g) 7.2.4 Less than 7/Minder as 7  NH4+(aq) + H2 ℓ)  ⇌ NH3(aq) + H3O+(aq)  Notes/Aantekeninge:  Ignore single arrow/Ignoreer enkelpyl:  (3) [21] QUESTION/VRAAG 8 8.1  Pressure: 1 atmosphere / 101,3 kPa /1,01 x 105 Pa  Druk: 1 atmosfeer / 101,3 kPa /1,01 x 105 Pa  Temperature/Temperatuur: 25 °C /298 K   Concentration of electrolytes: 1 mol·dm-3  Konsentrasie van elektroliete: 1 mol·dm-3 (3) 8.2 To maintain electrical neutrality/To complete the circuit/To allow movement of ions between electrolytes  Om elektriese neutraliteit te verseker/Om die stroombaan te voltooi/Laat ione toe om tussen elektroliete te beweeg (1) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 18 DBE/2023 SC/NSC/SS/NSS – Marking Guidelines/Nasienriglyne 8.3 OPTION 1/OPTION 1 Notes/Aantekeninge  Accept any other correct formula from the data cell cathode - a ode   sheet./Aanvaar enige ander korrekte formule 1,20 cathode  vanaf gegewensblad. cathode = 1,20 (V)   Any other formula using unconventional abbreviations, e.g. E°cell = E°OA - E°RA X is Pt/platinum  followed by correct substitutions:/Enige ander formule wat onkonvensionele afkortings gebruik, bv. E°sel = E°OM - E°RM gevolg deur korrekte vervangings: Max./Maks. 4 5 OPTION 2/OPSIE 2 X2+ + 2e- → X E  = 1,20 V   H2 → 2H+ + 2e- E  = 0,00 V  H2 + X2+ → X + 2H+ E  = 1,20 V  X is Pt/Platinum  (5) 8.4 H2(g)  2H+(aq) + 2e-  Marking criteria/Nasienkriteria:  2H+(aq) + 2e- ← H2(g) (2 2 ) H2(g) ⇌ 2H+(aq) + 2e-(1 ) 2 + - 0 + - 0 H2(g) ← 2H (aq) + 2e ( ) 2 2H (aq) + 2e ⇌ H2(g) ( ) 2  Ignore if charge omitted on electron./Ignoreer indien lading weggelaat op elektron.  If charge (+) omitted on H+/Indien lading (+) weggelaat op H+: - Example/Voorbeeld: H2(g)  2H(aq) + 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 19 DBE/2023 SC/NSC/SS/NSS – Marking Guidelines/Nasienriglyne 8.5 H+, X2+ (Pt2+), Au3+  H2 loses/donates electrons to both Au and X/Pt.  OR H2 is the anode/is oxidised in both cells. Therefore H+ is the weakest oxidising agent.  The reduction potential of X│X2+ is 1,2 a d that of Au│Au3+ is 1,5 V.  OR The reduction pote tial of X│X2+ is smaller than that of Au│Au3+. OR According to the Table of Standard Reduction Potentials Au3+ is stronger oxidation agent than Pt2+. OR The cell containing Au produces a higher emf than cell containing X.  H2 verloor/skenk elektrone aan beide Au en X/Pt.  OF H2 is die anode/word geoksideer in beide selle. Daarom is H+ die swakste oksideermiddel  Die reduksiepotensiaal van X│X2+ is 1, V en die van Au│Au3+ is 1,5 V.  OF Die reduksiepotensiaal van X│X2+ is kleiner as dié van Au│Au3+. OF Volgens die Tabel van Standaardreduksiepotensiale is Au3+ 'n sterker oksideermiddel as Pt2+ OF Die sel wat Au bevat het 'n hoër emk as die sel wat X bevat. (3) [14] Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 20 DBE/2023 SC/NSC/SS/NSS – Marking Guidelines/Nasienriglyne QUESTION/VRAAG 9 9.1 A cell in which electrical energy is converted into chemical energy.  (2 or 0) 'n Sel waar elektriese energie na chemiese energie omgeskakel word. (2 of 0) (2) 9.2 R Oxidation takes place./R loses electrons./R decreases in mass.  Oksidasie vind plaas./R verloor elektrone./R se massa sal afneem. (2) 9.3 9.3.1 Zn2+(aq) + 2e-  Zn(s)  Ignore phases/Ignoreer fases Marking criteria/Nasienkriteria:  Zn(s) ← Zn2+(aq) + 2e- (2 2 ) Zn2+(aq) + 2e- ⇌ Zn(s) (1 ) 2 2+ - 2+ - Zn (aq) + 2e ← Zn(s) (0 ) Zn(s) ⇌ Zn (aq) + 2e (0 ) 2 2  Ignore if charge omitted on electron./Ignoreer indien lading weggelaat op elektron.  If charge (+) omitted on Zn2+/Indien lading (+) weggelaat op Zn2+: 2 - Example/Voorbeeld: Zn (aq) + 2e  Zn(s) Max./Maks: 1 2 (2) 9.3.2 Zinc/Zn/Sink  (1) 9.4 Zn2+ ions are reduced/[Zn2+] decreases.  Zn2+ ions must be replaced by oxidation of the Zn electrode.  Zn2+ ione word gereduseer/[Zn2+] neem af. Zn2+ ione moet vervang word deur oksidasie van Zn-elektrode. (2) [9] TOTAL/TOTAAL: 150 Copyright reserved/Kopiereg voorbehou