Physical Sciences Grade 12 P2 Gauteng June 2025 Memo (Afr)

JUNE EXAMINATION JUNIE EKSAMEN GRADE/GRAAD 12 2025 MARKING GUIDELINES/ NASIENRIGLYNE PHYSICAL SCIENCES/ FISIESE WETENSKAPPE (PAPER/VRAESTEL 2) 14 pages/bladsye

PHYSICAL SCIENCES MARKING GUIDELINES FISIESE WETENSKAPPE NASIENRIGLYNE (PAPER/VRAESTEL 2) GR12 0625 QUESTION/VRAAG 1 1.1 C  (2) 1.2 C  (2) 1.3 D  (2) 1.4 D  (2) 1.5 B  (2) 1.6 A  (2) 1.7 C  (2) 1.8 D  (2) 1.9 B  (2) 1.10 A  (2) [20] 2

PHYSICAL SCIENCES MARKING GUIDELINES FISIESE WETENSKAPPE NASIENRIGLYNE (PAPER/VRAESTEL 2) GR12 0625 QUESTION/VRAAG 2 2.1 Secondary (alcohol)  The carbon bonded to the hydroxyl group/functional group is bonded to two other carbon atoms.  (2 or 0) Sekondêre (alkohol) Die koolstof wat aan die hidroksielgroep (funksionele groep) verbind is, is aan twee ander koolstofatome verbind. (2 of 0) (3) 2.2 2.2.1 G  (1) 2.2.2 A  (1) 2.2.3 B  (1) 2.3.1 H H H H H C C C C C H H H H H Marking criteria/Nasienkriteria: • Functional group between C2 and C3/Funksionele groep tussen C2 en C3  • Whole structure correct/Hele struktuur korrek  (2) 2.3.2  (2 or 0) Carbon must have 4 bonds/koolstof moet vier bindings hê (2) 2.3.3 H H C H H H H H O H C C C C C C H H H H H H (2) Marking criteria/Nasienkriteria: • Functional group/Funksionele groep  • Whole structure correct/Hele struktuur korrek  (2) 2.4 2.4.1 pent-2-ene/pent-2-een Accept 2-pentene Marking criteria/Nasienkriteria: • Correct stem/Korrekte stam  • IUPAC name completely correct/IUPAC-naam heeltemal korrek  If pentene only 1/2/indien penteen slegs 1/2 (2) 3

PHYSICAL SCIENCES MARKING GUIDELINES FISIESE WETENSKAPPE NASIENRIGLYNE (PAPER/VRAESTEL 2) GR12 0625 4

PHYSICAL SCIENCES MARKING GUIDELINES FISIESE WETENSKAPPE NASIENRIGLYNE (PAPER/VRAESTEL 2) GR12 0625 2.4.2 4-methylhexan-3-one/4-metielheksan-3-oon Marking criteria/Nasienkriteria: • Correct stem (hex)/Korrekte stam (heks)  • All substituents correctly identified/Alle substituente is korrek  • IUPAC name completely correct/IUPAC-naam heeltemal korrek  (3) 2.5.1 Positional isomers.  Posisionele isomere. (1) 2.5.2 Same molecular formula, but different positions of the side chain, substituants or functional group on the parent chain  Dieselfde molekulêre formule, maar verskillende posisies van die syketting, substituente of funksionele groep op die stamketting (2) 2.6 2.6.1 Ester/Ester  (1) 2.6.2 (Concentrated/Gekonsentreerde) sulphuric acid/swawelsuur  If the formula is given then zero Indien die formule gegee word, dan nul (1) 2.6.3 H H H O H C C C C H H H H H O C C H H H Marking criteria/Nasien kriteria: • Functional group/Funksionele groep  • Whole structure correct/Hele struktuur korrek  (3) [25] QUESTION/VRAAG 3 3.1 The pressure exerted by a vapour at equilibrium with its liquid in a closed system.  Die druk uitgeoefen deur ʼn damp in ewewig met sy vloeistof in ʼn geslote sisteem. (2) 3.2 Alkane/Alkaan  (1) 5

PHYSICAL SCIENCES MARKING GUIDELINES FISIESE WETENSKAPPE NASIENRIGLYNE (PAPER/VRAESTEL 2) GR12 0625 3.3 • Compound B has a longer chain/larger surface area / bigger molar mass than compound A.  • Both have the same London forces but the intermolecular forces in B are stronger.  • More energy is needed to overcome the intermolecular forces in compound B.  OR/OF • Compound A has a shorter chain/smaller surface area / smaller molar mass than compound B.  • Both have the same London forces but the intermolecular forces in A are weaker.  • Less energy is needed to overcome the intermolecular forces in compound A.  • Verbinding B het ʼn langer ketting/groter oppervlakte/groter molêre massa as verbinding A. • Albei het dieselfde Londonkragte maar die intermolekulêre kragte in B is sterker. • Meer energie is nodig om die intermolekulêre kragte in verbinding B te oorkom. OR/OF • Verbinding A het ʼn korter ketting/kleiner oppervlakte/kleiner molêre massa as verbinding A. • Albei het dieselfde Londonkragte maar die intermolekulêre kragte in A is swakker. • Minder energie is nodig om die intermolekulêre kragte in verbinding A te oorkom. (3) 3.4 3.4.1 A chemical formula that indicates the element and numbers of each of the atoms in a molecule.  (2 or 0) 'n Chemiese formule wat die element en getalle van elk van die atome in 'n molekule aandui. (2 of 0) (2) 3.4.2 E or propanoic acid/E of propanoësuur  (1) 3.4.3 • Compound E has hydrogen bonds  • Compound C has dipole-dipole forces  • Stronger intermolecular forces in compound E than in C  • More energy required to overcome the intermolecular forces in E  • Verbinding E het waterstofbindings • Verbinding C het dipool-dipool kragte • Sterker intermolekulȇre kragte in verbinding E as in C • Meer energie word benodig om die intermolekulȇre kragte in E te oorkom (4) 6

PHYSICAL SCIENCES MARKING GUIDELINES FISIESE WETENSKAPPE NASIENRIGLYNE (PAPER/VRAESTEL 2) GR12 0625 3.5 Marking criteria/Nasienriglyn: • Calculate the % of oxygen in the alcohol.  𝑚𝑚 • Substitute 61; 11,86 and 27,14 in the formula 𝑛𝑛 = 𝑀𝑀  • Divide by the smallest mols 1,696  • Correct empirical formula  • Bereken die % suurstof in die alkohol. 𝑚𝑚 • Vervang 61; 11,86 en 27,14 in die formule 𝑛𝑛 = 𝑀𝑀 • Deel deur die kleinste mol hoeveelheid 1,696 • Korrekte empiriese formule m n = Element % m = 100g M M Ratio 61 = 5,08 5,08 C 61 12 12  = 2,99 1,696 11,86 = 11,86 11,86 H 11,86 1 1 = 6,99 1,696 27,14 = 1,696 1,696 O 27,14  16 16 = 1  1,696 Correct empirical formula/Korrekte empiriese formule : C3H7O  (4) 3.6 C3H8 + 5O2 → 3 CO2 + 4 H2O   balancing/balansering (3) [20] QUESTION/VRAAG 4 4.1 Unsaturated,  there are one or more multiple bonds between two carbon atoms in the hydrocarbon chain.  Onversadig, daar is een of meer meervoudige bindings tussen C-atome in die koolwaterstofketting (3) 4.2 4.2.1 Addition/Hydrogenation  Addisie/Hidrogenering/Hidrogenasie (1) 4.2.2 Substitution/ halogenation  Substitusie/halogenering (1) 4.2.3 Elimination/dehydrohalogenation  Eliminasie/dehidrohalogenering (1) 7

PHYSICAL SCIENCES MARKING GUIDELINES FISIESE WETENSKAPPE NASIENRIGLYNE (PAPER/VRAESTEL 2) GR12 0625 4.3 H Cl H H H C C C C H H H H H Marking criteria/nasienriglyne  Chlorine on carbon 2/Chloor op koolstof 2  Whole structure/Hele struktuur (2) 4.4 4.4.1 Hydration  Hidratering/Hidrasie (1) 4.4.2 Excess water/H2O  Small amount of strong acid as catalyst  / sulfuric acid (H2SO4) or phosphoric acid (H3PO4). Oormaat water/H2O Klein hoeveelheid van ‘n sterk suur as katalis / swawelsuur (H2SO4) of fosforsuur (H3PO4). (2) 4.4.3 Butan-2-ol  accept: 2-butanol Butan-2-ol aanvaar: 2-butanol (2) 4.5 2-methylpropane or methylpropane 2-metielpropaan of metielpropaan (2) 4.6 H H H H H H H H    H C C C C H + HBr H C C C C H + H2O H H O H H H Br H   H Marking criteria/Nasienkriteria: • Correct structural formula of butan-2-ol  the OH is on the correct carbonand HBr  • Correct structural formula of 2-bromobutane and H2O  • Korrekte struktuurformule vir butan-2-ol die OH is op die regte koolstof en HBr • Korrekte struktuurformule vir 2-bromobutaan en H2O If condensed structural formulae used max 2/5 Indien gekondenseerde struktuurformules gebruik maks 2/5 (5) [20] 8

PHYSICAL SCIENCES MARKING GUIDELINES FISIESE WETENSKAPPE NASIENRIGLYNE (PAPER/VRAESTEL 2) GR12 0625 QUESTION/VRAAG 5 5.1 Reaction rate is the change in concentration of reactants or products per unit time   (2 or 0) Verandering in konsentrasie van reaktante of produkte per eenheid tyd. (2 of 0) (2) 5.2 • Number of particles per unit volume decrease  • Fewer particles with enough energy available for collision  • Fewer effective collisions per unit time,/lower frequency of effective collisions • Reaction rate decreases/Lower reaction rate/Reaction slows down • Hoeveelheid deeltjies per eenheid volume verlaag. • Minder deeltjies het genoeg energie beskikbaar vir botsings • Minder effektiewe botsings per eenheid tyd/laer frekwensie van effektiewe botsings Reaksietempo verlaag/Laer reaksietempo/Reaksie word stadiger (4) 5.3 ∆V(CO2 ) Rate/Tempo = ∆t 0,3 − 0 = 20 − 0 (3) = 0,015  (dm3.s-1) 9

PHYSICAL SCIENCES MARKING GUIDELINES FISIESE WETENSKAPPE NASIENRIGLYNE (PAPER/VRAESTEL 2) GR12 0625 5.4 Marking criteria/Nasienkriteria: 𝑉𝑉 (a) Substitute/ Vervang 24 in n = 𝑉𝑉 correctly with 0,5/korrek met 0,5 𝑚𝑚 (b) USE/GEBRUIK mole ratio/mol verhouding 1:1 MgCO3 : CO2  (c) Molar mass of MgCO3 (84) in the correct formula  Molêre massa van MgCO3 (84) in die korrekte formule (d) Final answer range 1,68 g – 1,75 g  Finale antwoordreeks 1,68 g – 1,75 g V(CO2) = 500 cm3 /1000 = 0,5 dm3 Vm = 24 dm3 V n= Vm 0,5 = 24 (𝒂𝒂) = 0,02 mol MgCO3 : CO2 1:1 0,02: 0,02  (b) m n(MgCO3) = M m 0,02 =  (𝐜𝐜) 84 m = 1,75 g  (d) (4) 5.5 5.5.1 Graph/Grafiek B  (1) 5.5.2 • A peak/maximum at a higher kinetic energy/peak shifted to the right.  • More molecules have Ek > Ea  • ‘n Piek/maksimum by ‘n hoër kinetiese energie/piek skuif na regs. • Meer molekule het Ek > Ea (2) 5.5.3 LEFT/LINKS  (1) 10

PHYSICAL SCIENCES MARKING GUIDELINES FISIESE WETENSKAPPE NASIENRIGLYNE (PAPER/VRAESTEL 2) GR12 0625 5.6 5.6.1 Exothermic/Eksotermies (1) 5.6.2 B  or D (1) 5.6.3 10 (kJ)  (1) [20] 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 een van die onderstreepte sleutelfrases in die korrekte konteks weggelaat word, 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 oppose the disturbance.  (do not accept isolated system) Wanneer die ewewig in ʼn geslote sisteem versteur word,stel die sisteem ʼn nuwe ewewig in deur die reaksie wat die versteuring teenwerk te bevoordeel. (moet nie geïsolleerde sisteem aanvaar nie) (2) 6.2 Marking criteria/Nasienkriteria: (a) USING ratio/GEBRUIK verhouding n(CS2): n(Cℓ2): n(CCℓ4): n(S2Cℓ2) = 1:3:1:1.  (b) nequilibrium/ewewig = ninitial/aanvanklik –/+ nchange/verandering  (c) Divide nequilibrium by the volume 2 dm3  Deel newewig deur die volume 2 dm3 (d) Correct Kc expression (formulae in square brackets).  Korrekte Kc uitdrukking (formule in blokhakkies). (e) Substitute Kc value 0,36  Vervang die Kc waarde 0,36 (f) Substitution of equilibrium concentrations into Kc expression. Vervang ewewigkonsentrasies in Kc uitdrukking (g) Solve for 𝑥𝑥 /Los op vir 𝑥𝑥  (h) Final answer/Finale antwoord: 1,21 mol (1,20459 mol)  11

PHYSICAL SCIENCES MARKING GUIDELINES FISIESE WETENSKAPPE NASIENRIGLYNE (PAPER/VRAESTEL 2) GR12 0625 OPTION 1/OPSIE 1 CS2(g) Cℓ2(g) CCℓ4(g) S2Cℓ2(g) Initial amount 𝑥𝑥 5 0 0 moles/Aanvanklike mol hoeveelheid Change in amount -0,8 -2,4 +0,8 +0,8 (a) (moles)/Verandering in hoeveelheid(mol) Equilibrium amount (moles)/ 𝑥𝑥 – 0,8 2,6 0,8 0,8 (b) /Ewewigshoeveelheid Equilibrium concentration/ 𝑥𝑥 – 0,8 2,6 0,8 0,8 = = = 0,4 Ewewigskonsentrasie 2 2 2 2 (mol.dm-3) 1,3 0,4 (c) [ CCℓ4 ][S2 Cℓ2 ] Kc = (d) [CS2 ][ Cℓ2 ]3 No Kc expression, correct substitution (0,4)(0,4) 0,36 (e)= (f) Max 7/8 [C𝑆𝑆2 ](1,3)3 [CS2 ] = 0,202… Wrong Kc expression Max 4/8 x – 0,8 (𝐠𝐠)= 0,202… Geen Kc uitdrukking, korrekte vervanging 2 𝑥𝑥 = 1,20 mol (h) (1,20459 Maks 7/8 mol) Verkeerde Kc uitdrukking Maks 4/8 OPTION 2/OPSIE 2 CS2(g) Cℓ2(g) CCℓ4(g) S2Cℓ2(g) Initial concentration/Aanvanklike 𝑥𝑥 2,5 0 0 konsentrasie 2 (c) Change in concentration -0,4 -1,2 +0,4 +0,4 (a) /Verandering in konsentrasie Equilibrium concentration/ 𝑥𝑥 – 0,8 Ewewigskonsentrasie 2 1,3 0,4 0,4 (b) (mol.dm-3) [ CCℓ4 ][S2 Cℓ2 ] Kc = (d) [CS2 ][ Cℓ2 ]3 No Kc expression, correct substitution (0,4)(0,4) 0,36 (e)= (f) Max 7/8 [C𝑆𝑆2 ](1,3)3 [CS2 ] = 0,202… Wrong Kc expression Max 4/8 x – 0,8 (𝐠𝐠)= 0,202… Geen Kc uitdrukking, korrekte vervanging 2 𝑥𝑥 = 1,20 mol (h) (1,20459 Maks 7/8 mol) Verkeerde Kc uitdrukking Maks 4/8 (8) 12

PHYSICAL SCIENCES MARKING GUIDELINES FISIESE WETENSKAPPE NASIENRIGLYNE (PAPER/VRAESTEL 2) GR12 0625 6.3.1 Increase  Removing the carbon tetrachloride will decrease the concentration of the product the system will try to increase the products by favouring the forward reaction concentration of reactants will decrease and products will increase. Vermeeder Die verwydering van die koolstoftetrachloried sal die konsentrasie van die produk verlaag, die stelsel sal probeer om die produkte te verhoog deur die voorwaartse reaksie te bevoordeel, konsentrasie van reaktante sal afneem en produkte sal toeneem (2) 6.3.2 Decrease  Volume is increased then pressure is decreased. The system will counteract the change by favouring the reaction that produces the greater amount of moles. Therefore, the reverse reaction is favoured the concentration of reactants will increase and products will decrease. Verminder Volume word verhoog en druk verminder. Die sisteem sal die verandering teëwerk deur die reaksie te bevoordeel wat die meeste mol produseer. Daarom word die terugwaartse reaksie bevoordeel, die konsentrasie van reaktante sal toeneem en produkte sal afneem. (2) 6.4.1 Decreased/Verlaag  (1) 6.4.2 • Temperature INCREASES  • Increase in temperature favours endothermic reaction  • Reverse reaction is favoured  • Reverse reaction is endothermic  • Temperatuur VERHOOG • Toename in temperatuur bevoordeel endotermiese reaksie • Terugwaartse reaksie word bevoordeel • Terugwaartse reaksie is endotermies (4) 6.4.3 22 (minutes/minute)  (1) [20] QUESTION/VRAAG 7 7.1 Weak acids ionise incompletely in water  to form a low concentration of H3O+ ions. Swak sure ioniseer onvolledig in water om 'n lae konsentrasie H3O+-ione te vorm. (2) 7.2 H2C2O4 ; 𝐻𝐻𝐶𝐶2 O-4  OR/OF H3O+; H2O (2) 13

PHYSICAL SCIENCES MARKING GUIDELINES FISIESE WETENSKAPPE NASIENRIGLYNE (PAPER/VRAESTEL 2) GR12 0625 7.3 Oxalic acid can donate two protons (H⁺) during its ionisation in an aqueous solutions/It ionises to form 2 protons. Oksaalsuur kan twee protone (H⁺) skenk tydens die ionisasie daarvan in ʼn waterige oplossings/Dit ioniseer om 2 protone te vorm. (1) 7.4 A substance that can act as either an acid or a base. Accept: a substance that can donate or accept a proton 'n Stof wat as beide 'n suur of 'n basis kan reageer. Aanvaar: ‘n stof wat ‘n proton kan skenk of ontvang (1) 7.5.1 OPTION 1/OPSIE 1 OPTION 2/OPSIE 2 m m n c=  n= c=  MV M V = 2,25  = 2,25 (for both formulae/vir beide 90(0,25) 90 formules) = 0,1 mol.dm-3  = 0,025 mol 0,025 =  0,25 = 0,1 mol.dm-3  (3) 7.5.2 Positive marking from 7.5.1/positiewe nasien vanaf 7.5.1 Marking criteria/Nasienkriteria: n ca Va na (a) Any formula/Enige formule c= OR = V cb Vb nb (b) Substitution/Vervanging (c) USE mole ratio/GEBRUIK mol verhouding H2C2O4 : NaOH as 1 : 2 (d) Final answer/Finale antwoord: 0,18 mol.dm-3 (accept/aanvaar 0,175 mol.dm-3) OPTION/OPSIE 1 OPTION/OPSIE 2 𝑛𝑛 ca Va na c(H2C2O4) = 𝑉𝑉 (a) =  (a) cb Vb nb n = (0,1)(0,025) (b) (0,1)(0,025) 1  (b) = (c) = 0,025 mol cb (0,0286) 2 n c(NaOH) = cb = 0,18 mol.dm-3 (d) V 2(0,0025) = (c) 0,0286 = 0,18 mol.dm-3 (d) (4) 14

PHYSICAL SCIENCES MARKING GUIDELINES FISIESE WETENSKAPPE NASIENRIGLYNE (PAPER/VRAESTEL 2) GR12 0625 7.5.3 Phenolphthalein is a suitable indicator for the titration of oxalic acid and sodium hydroxide because the reaction involves a strong base (NaOH) and a weak acid (H2C2O4). The endpoint of the titration occurs when the pH is greater than 7  OR Because the salt of the titration will undergo hydrolysis and form a basic salt solution. Fenolftaleïen is 'n geskikte indikator vir die titrasie van oksaalsuur en natriumhidroksied omdat die reaksie tussen 'n sterk basis (NaOH) en 'n swak suur (H2C2O4) is. Die eindpunt van die titrasie word bereik wanneer die pH groter as 7 is. OF Omdat die sout van die titrasie hidrolise sal ondergaan en 'n basiese soutoplossing sal vorm. (2) 7.6 Marking criteria/Nasienkriteria: (a) Substitution/Vervanging (Mg(OH)₂) : (0,115)(0,05)  (b) Substitution/Vervanging (HNO₃) : (0,095)(0,025)  (c) USE ratio/GEBRUIK verhouding: 2n(HNO₃): = n(Mg(OH)₂)  (d) n(Mg(OH)₂)excess/oormaat = ninitial/aanvanklik – nreacted/gereageer = 0,00575 - 0,0011875 (e) Use the ratio 2 OH- : Mg(OH)₂ (f) Substitute/Vervang 0,075 dm3  (g) Use/gebruik Kw = [H3O+] [OH-]  (h) Substitute/Vervang [OH-] = 0,12166  (i) Formula/Formula pH = - log [H3O+]  (j) Range for final answer/Gebied vir finale antwoord: (13,08 - 13,12)  15

PHYSICAL SCIENCES MARKING GUIDELINES FISIESE WETENSKAPPE NASIENRIGLYNE (PAPER/VRAESTEL 2) GR12 0625 n n c(Mg(OH)₂) = c(HNO₃) = V V n = (0,115)(0,05)  (a) n = (0,095)(0,025) (b) = 0,00575 mol = 0,002375 mol HNO₃ : Mg(OH)₂ 2:1 0,002375 : 0,0011875 (c) n(Mg(OH)₂ )excess/oormaat = ninitial/aanvanklik – nreacted/gereageer =0,00575 – 0,0011875 = 0,0045625 mol (d) OH- : Mg(OH)₂ 2:1 0,009125 : 0,0045625 (e) n c[OH-]= V 0,009125 = (𝐟𝐟) 0,075 = 0,12166 mol.dm-3 Kw = [H3O+] [OH-] (g) pH = - log [H3O+]  (i) = - log (8,219 × 10-14) 1 × 10-14 = [H3O+] [0,12166] (h) = 13,082(j) [H3O+] = 8,219 × 10-14 OR/OF pH + pOH = 14 pH = 14 – (– log [OH-]) = 14 – (- log(0,12166)) = 13,085 (10) [25] TOTAL/TOTAAL: 150 16