Physical Sciences Grade 12 Paper 2 NSC June 2018 Memo

Downloaded from hlayiso.com SENIOR CERTIFICATE EXAMINATIONS SENIORSERTIFIKAAT-EKSAMEN PHYSICAL SCIENCES: CHEMISTRY (P2) FISIESE WETENSKAPPE: CHEMIE (V2) 2018 MARKING GUIDELINES/NASIENRIGLYNE MARKS/PUNTE: 150 These marking guidelines consist of 15 pages. Hierdie nasienriglyne bestaan uit 15 bladsye. Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 2 DBE/2018 SCE/SSE – Marking Guidelines/Nasienriglyne QUESTION 1/VRAAG 1 1.1 D  (2) 1.2 A  (2) 1.3 B  (2) 1.4 B  (2) 1.5 D  (2) 1.6 C  (2) 1.7 B  (2) 1.8 D  (2) 1.9 D  (2) 1.10 C  (2) [20] QUESTION 2/VRAAG 2 2.1 2.1.1 A (1) 2.1.2 D (1) 2.1.3 B (1) 2.1.4 E (1) 2.1.5 B (1) 2.2 Marking criteria/Nasienriglyne  • Whole structure correct: 2.2.1 H O H Hele struktuur korrek: 2 H C O C C H 2  • Only functional group correct:/Slegs H H funksionele groep korrek: Max/Maks.: 1 2 OR/OF Accept/Aanvaar H H O Any correct arrangement of correct number of H O H atoms C C C Enige korrekte struktuur met die korrekte aantal atome. H H (2) 2.2.2 ANY ONE/ENIGE EEN: Methyl ethanoate /metieletanoaat OR/OF Ethyl methanoate //etielmetanoaat (2) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 3 DBE/2018 SCE/SSE – Marking Guidelines/Nasienriglyne 2.3 2.3.1 A large molecule composed of smaller monomer units covalently bonded to each other in a repeating pattern.  'n Groot molekuul wat uit kleiner monomeer-eenhede bestaan wat kovalent aan mekaar in 'n herhalende patroon gebind is.  (2) 2.3.2 Polyethene  Polieteen Accept/Aanvaar: Polyethylene/polythene Poli-eteen/poli-etileen/politeen (1) 2.3.3 H H H H H H n C C C C OR/OF ... C C ... H H H H n H H Accept as reactant/Aanvaar as reaktans: Marking guidelines/Nasienriglyne • Structure shows TWO C atoms with n CH2 CH2 four bonds (ethene) each and FOUR H atoms./Struktuur toon TWEE C- n C2H4 atome met vier bindings (eteen) elk na VIER H-atome.  Accept as product/Aanvaar as produk: • Structure of product / Struktuur van produk.  CH2 CH2 n • Multiple n and brackets correctly shown for reactant and product./Veelvoud n en hakie korrek getoon vir reaktans en produk.  (3) 2.4 Hydrolysis/Substitution  Hidrolise/Substitusie (1) 2.5 • Use concentrated strong base/NaOH/KOH/LiOH OR ethanolic/alcoholic strong base/NaOH/KOH/LiOH. /Use ethanol instead of water./No water. Gebruik gekonsentreerde sterk basis/NaOH/KOH/LiOH OF etanoliese / alkoholiese sterk basis/NaOH/KOH/LiOH /Gebruik etanol in plaas van water./Geen water nie. • Heat strongly/Verhit sterk  Accept/Aanvaar: Increase temperature/Verhoog temperatuur (2) [18] Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 4 DBE/2018 SCE/SSE – Marking Guidelines/Nasienriglyne QUESTION 3/VRAAG 3 3.1 • Structure/Struktuur: The chain length/molecular size /molecular structure/molecular mass/ surface area increases.  Die kettinglengte/molekulêre grootte/molekulêre struktuur/molekulêre massa/oppervlakte neem toe. • Intermolecular forces/Intermolekulêre kragte: Increase in strength of intermolecular forces/induced dipole /London/ dispersion /Van der Waals forces/momentary dipoles.  Toename in sterkte van intermolekulêre kragte/geïnduseerde dipoolkragte/Londonkragte/dispersiekragte/Van der Waalskragte / momentele dipool. • Energy/Energie: More energy needed to overcome/break intermolecular forces.  Meer energie benodig om intermolekulêre kragte te oorkom/breek. OR/OF • Structure/Struktuur: From 4 C atoms to 1 C atom/bottom to top the chain length/molecular size/molecular structure/molecular mass/surface area decreases.  Van 4 C-atome na 1 C-atoom/onder na bo neem die kettinglengte/ molekulêre grootte/molekulêre struktuur/molekulêre massa/oppervlakte af. • Intermolecular forces/Intermolekulêre kragte: Decrease in strength of intermolecular forces/ induced dipole forces/ London forces/dispersion forces.  Afname in sterkte van intermolekulêre kragte/geïnduseerde dipoolkragte/ Londonkragte/dispersiekragte. • Energy/Energie: Less energy needed to overcome/break intermolecular forces.  Minder energie benodig om intermolekulêre kragte te oorkom/breek. (3) 3.2 • Alkanes have London/dispersion/induced dipole forces.  Alkane het London-/dispersie-/geïnduseerde dipoolkragte. • Alcohols have hydrogen bonding (in addition to London/dispersion/ induced dipole forces and dipole dipole forces).  Alkohole het waterstofbinding (in toevoeging tot London-/dispersie-/ geïnduseerde dipoolkragte en dipoolkragte). • Hydrogen bonding are stronger intermolecular forces than London/ dispersion/ induced dipole forces.  Waterstofbindings is sterker intermolekulêre kragte as London-/dispersie- /geïnduseerde dipoolkragte. OR/OF More energy needed to overcome/break intermolecular forces in alcohols Meer energie benodig om intermolekulêre kragte te oorkom/breek in alkohole. • Alcohols have higher boiling points than alkanes.  Alkohole het hoër kookpunte as die alkane. (4) 3.3 Decrease/Neem af  (1) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 5 DBE/2018 SCE/SSE – Marking Guidelines/Nasienriglyne 3.4 Lower than/Laer as  - 2-methylpropane/It is more branched/has a smaller surface area/has a shorter chain length (than butane/chain isomer)  2-metielpropaan/Dit is vertak/het 'n kleiner oppervlakte/het 'n korter kettinglengte (as butaan/ketting-isomeer). OR/OF Butane/chain isomer is less branched /has larger surface area/longer chain length (than 2-methylpropane). Butaan/ketting-isomeer is minder vertak/het 'n groter oppervlakte/het 'n langer kettinglengte (as 2-metielpropaan). (2) [10] QUESTION 4/VRAAG 4 4.1 4.1.1 Substitution/halogenation/bromonation Substitusie/halogenering/halogenasie/brominering/brominasie (1) 4.1.2 Elimination/dehydration  Eliminasie/dehidrasie/dehidratering (1) 4.1.3 Esterification/condensation  Esterifikasie/verestering/kondensasie (1) 4.1.4 Addition/hydrohalogenation/hydrobromonation  Addisie/hidrohalogenasie/hidrohalogenering/hidrobrominasie/hidrobromonering (1) 4.2 4.2.1 Catalyst/dehydrating agent/speeds up reaction  Katalisator/dehidreermiddel/versnel die reaksie (1) 4.2.2 Propyl  ethanoate /Propieletanoaat (2) 4.2.3  Marking criteria/Nasienriglyne: H O • Whole structure correct Hele struktuur korrek: 2 H C C O H  2 • Only functional group correct H 1 Slegs funksionele groep korrek: 2 IF/INDIEN: More than one functional group/Meer as een funksionele groep 0 2 (2) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 6 DBE/2018 SCE/SSE – Marking Guidelines/Nasienriglyne 4.3 H H H H H H   H C C C H + HBr  H C C C H + H2O  H H O H H Br  H Notes/Aantekeninge: • Ignore/Ignoreer ⇌ • Accept HBr and H 2 O as condensed. /Aanvaar HBr en H 2 O as gekondenseerd. • Any additional reactants and/or products Enige addisionele reaktanse en/of produkte: Max./Maks. 4 5 • Accept coefficients that are multiples. Aanvaar koëffisiënte wat veelvoude is. • Incorrect balancing/Verkeerde balansering: Max./Maks. 4 5 • Molecular/condensed formulae Molekulêre/gekondenseerde formule: Max./Maks. 2 5 (5) [14] QUESTION 5/VRAAG 5 5.1 ONLY ANY ONE OF/SLEGS ENIGE EEN VAN: • Change in concentration of products/reactants  per (unit) time.  Verandering in konsentrasie van produkte/reaktanse per (eenheids)tyd. • Rate of change in concentration.  Tempo van verandering in konsentrasie. • Change in amount/number of moles/volume/mass  of products or reactants per (unit) time.  Verandering in hoeveelheid/aantal mol/volume/massa van produkte of reaktanse per (eenheids)tyd. • Amount/number of moles/volume/mass (of products) formed/(reactants) used per (unit) time. Hoeveelheid/aantal mol/volume/massa (van produkte) gevorm/(reaktanse) gebruik per (eenheids)tyd. (2) 5.2 5.2.1 Surface area/State of division  Oppervlakte/Toestand van verdeeldheid (1) 5.2.2 ANY ONE/ENIGE EEN: • Amount/mass of magnesium  Hoeveelheid/massa magnesium • Concentration of HCℓ/acid/Konsentrasie van HCℓ /suur • (Initial) temperature/(Aanvanklike) temperatuur (1) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 7 DBE/2018 SCE/SSE – Marking Guidelines/Nasienriglyne 5.3 5.3.1 Marking criteria/Nasienriglyne • Calculate change in m(Mg) or n(Mg)  Bereken verandering in m(Mg) of n(Mg) m • Substitute/Vervang 24 g∙mol-1 in n =  M • Use mol ratio/Gebruik molverhouding: n(Mg) = n(H 2 ) = 1:1  V • Substitute/Vervang 25 dm3 in n = . Vm • Final answer/Finale antwoord: 2,5 dm3  OPTION 1/OPSIE 1 OPTION 2/OPSIE 2 △m(Mg) = 2,6 - 0,2  m 2,6 n(Mg) t =2s = = = 0,1083 mol = 2,4 g M 24  m n(Mgused /gebruik ) = 0,2 M n(Mg) t =10 s = = 0,0083 mol 2,4 24 = 24  △n(Mg) = 0,1083 - 0,0083  = 0,1 mol = 0,1 mol n(H 2 ) = n(Mg) = 0,1 mol  n(H 2 ) = n(Mg) = 0,1 mol  V(H 2 ) = nV m V(H 2 ) = nV m V(H 2 ) = (0,1)(25)  V(H 2 ) = (0,1)(25)  = 2,5 dm3  = 2,5 dm3  OPTION 3/OPSIE 3 24 g Mg  25 dm3 H 2 ∴ 2,4 g  x dm3 H 2 2,4 × 25  x=  24 = 2,5 dm3  (5) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 8 DBE/2018 SCE/SSE – Marking Guidelines/Nasienriglyne 5.3.2 Marking criteria/Nasienriglyne ∆n • Substitute/Vervang 2,08 x 10-4 in ave rate / gem. tempo =  ∆t ∆n • Substitute/Vervang 10 x 60 s (600 s) in ave rate / gem. tempo =  ∆t • Use mol ratio/Gebruik molverhouding: n(Mg) = n(H 2 ) = 1:1  • Substitute/Vervang 24 g∙mol-1 in m = nM.  • Final answer/Finale antwoord: 3 g  (Range/Gebied 2,995 – 3,12 g) ∆n ave rate / gem. tempo = ∆t  ∆n ∴ 2,08 x 10-4 = (10 × 60) − 0  ∴ △n = 0,125 mol n(Mg) = n(H 2 ) = 0,125 mol  m(Mg) = nM m(Mg) = 0,125 x 24  = 3 g  (2,995 g) (5) 5.4 • Larger surface area/state of division.  Groter reaksieoppervlak/toestand van verdeeldheid • More particles (per volume) with correct orientation/Meer deeltjies (per volume) met korrekte oriëntasie.  OR/OF More contact points./Meer kontakpunte. • More effective collisions per (unit) time./Frequency of effective collisions increases./More particles collide with sufficient kinetic energy & correct orientation per (unit) time. Meer effektiewe botsings per (eenheids)tyd./Frekwensie van effektiewe botsings verhoog./Meer deeltjies bots met genoeg kinetiese energie & korrekte oriëntasie per tyd(seenheid). (3) [17] Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 9 DBE/2018 SCE/SSE – 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./Both forward and reverse reactions take place at same rate.  Die stadium in 'n chemiese reaksie wanneer die tempo van die voorwaartse reaksie gelyk is aan die tempo van die terugwaartse reaksie./Beide voor- en terugwaartse reaksies vind teen dieselfde tempo plaas. 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) 6.2 6.2.1 2 (1) 6.2.2 1 (1) 6.2.3 3 (1) 6.3 POSITIVE MARKING FROM QUESTION 6.2. POSITIEWE NASIEN VANAF VRAAG 6.2. Marking criteria/Nasienriglyne: n • Substitute/Vervang 8 mol in c =  V n • Substitute/Vervang 4 mol in c =  V n • Substitute/Vervang 12 mol in c =  V • Substitute/Vervang V = 3 dm3 in the above THREE formulae/in die bostaande DRIE formules.  • K c expression/uitdrukking  • Substitution of concentrations into K c expression  Vervanging van konsentrasies in K c -uitdrukking. • Final answer/Finale antwoord: 6,75  OPTION 1/OPSIE 1 8 [A] = = 2,67 mol∙dm-3 3 4 [B] = = 1,33 mol∙dm-3 Divide by/Deel deur 3 dm3  3 12  [C] = = 4 mol∙dm-3 3 No Kc expression, correct substitution /Geen Kc- [C]3 uitdrukking, korrekte substitusie: Max./Maks. 6 Kc =  7 [ A ] 2 [B] ( 4 )3 Wrong Kc expression /Verkeerde Kc-uitdrukking: =  (2,67)2 (1,33) Max./Maks. 4 7 = 6,75  Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 10 DBE/2018 SCE/SSE – Marking Guidelines/Nasienriglyne OPTION 2/OPSIE 2 A B C Initial quantity (mol) 16 8 0 Aanvangshoeveelheid (mol) Change (mol) 8 4 12 Verandering (mol) Quantity at equilibrium (mol) 8 4 12  Hoeveelheid by ewewig (mol) Equilibrium concentration (mol∙dm-3) 8 4 12 Divide by Ewewigskonsentrasie (mol∙dm-3) /deel deur 3 3 3 3 dm3  [C]3 No Kc expression, correct substitution /Geen Kc- Kc =  [ A ] 2 [B] uitdrukking, korrekte substitusie: Max./Maks. 6 ( 4 )3 7 =  (2,67)2 (1,33) Wrong Kc expression /Verkeerde Kc-uitdrukking: = 6,75  Max./Maks. 4 7 (7) USING CONCENTRATION/GEBRUIK KONSENTRASIE OPTION 3/OPSIE 3 A B C -3 Initial concentration (mol∙dm ) 16 8 Aanvangskonsentrasie (mol∙dm-3) = 5,33 = 2,67 0 3 3 Change (mol∙dm-3) 8 4 12 3 Verandering (mol∙dm-3) = 2,67 = 1,33 =4 3 3 3 dm3  Equilibrium concentration (mol∙dm-3) 8 4 12 Ewewigskonsentrasie (mol∙dm-3) = 2,67  = 1,33  = 4 3 3 3 [C]3 Kc =  [ A ] 2 [B] No Kc expression, correct substitution /Geen Kc- ( 4 )3 uitdrukking, korrekte substitusie: Max./Maks. 6 = 7 (2,67)2 (1,33) = 6,75  Wrong Kc expression /Verkeerde Kc-uitdrukking: Max./Maks. 4 7 (7) 6.4 Endothermic/Endotermies  - • (An increase in temperature) favours the reverse reaction.  ('n Toename in temperatuur )bevoordeel die terugwaartse reaksie. • An increase in temperature favours an endothermic reaction.  'n Toename in temperatuur bevoordeel 'n endotermiese reaksie. (3) [15] Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 11 DBE/2018 SCE/SSE – Marking Guidelines/Nasienriglyne QUESTION 7/VRAAG 7 7.1 Titration/Volumetric analysis  Titrasie/Volumetriese analise (1) 7.2 To measure the (exact) volume of acid needed to reach endpoint/to neutralise the base.  Om die (presiese) volume suur te meet wat benodig word om die eindpunt te bereik/om die basis te neutraliseer. (1) 7.3 Acids produce hydrogen ions (H+)/hydronium ions (H 3 O+) in solution/when dissolved in water.  Sure vorm waterstofione(H+)/hidroniumione (H 3 O+) in oplossing/wanneer opgelos in water. IF/INDIEN: Acids produce hydrogen ions (H+)/hydronium ions (H 3 O+).  Sure vorm waterstofione(H+)/hidroniumione (H 3 O+). (2) 7.4 H 2 SO 4 ionises completely./ H 2 SO 4 ioniseer volledig.  (1) 7.5 Blue to yellow/Blou na geel  (1) 7.6 Marking guidelines/Nasienriglyne: n c × Va n a • Formula/Formule: c = /n = cV/ a =  V c b × Vb n b • Substitution of/Vervanging van: (0,1)(25)/(0,1)(0,025)  • Use mol ratio/Gebruik molverhouding: n a : n b = 1 : 2  • Final answer/Finale antwoord: 12,5 cm3 / 0,0125 dm3  OPTION 1/OPSIE 1 OPTION 2/OPSIE 2 c a Va na n =  cb =  c b Vb nb V n 0,1 =  (0,1 )Va 1 0,025 =  (0,1)(25) 2 n b = 2,5 x 10-3 mol ∴ V a = 12,5 cm3  1 1 na = nb = (2,5 x 10-3)  2 2 = 1,25 x 10-3 mol n ca = V 1,25 × 10 −3 0,1 = V ∴ V a = 0,0125 dm3 /12,5 cm3  (4) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 12 DBE/2018 SCE/SSE – Marking Guidelines/Nasienriglyne 7.7 POSITIVE MARKING FROM QUESTION 7.6. POSITIEWE NASIEN VANAF VRAAG 7.6. Marking guidelines/Nasienriglyne: n • Formula/Formule: c =  V • Substitution of/Vervanging van: (0,1)(0,005)/0,0175 in n = cV  • Substitute/Vervang V = 0,0425 dm3  • Use/Gebruik [H 3 O+] : [H 2 SO 4 ] = 2 : 1  • Formula/Formule: pH = -log[H 3 O+]  • Substitute/Vervang [H+]  • Final answer/Finale antwoord: 1,63  OPTION 1/OPSIE 1 OPTION 2/OPSIE 2 n a(excess/oormaat) = cV  n a(final/finaal) = cV  = (0,1)(0,005)  = (0,1)(0,0175)  = 5 x 10-4 mol = 1,75 x 10-3 mol n n a(exs/oor) = n a(final/finaal) - n a(react/reageer) ca = = 1,75 x 10-3 – 1,25 x 10-3 V = 5 x 10-4 mol 5 × 10 −4 = 4,25 × 10 −2  n ca = = 1,18 x 10-2 mol·dm-3 V c(H+) = 2c a 5 × 10 −4 = = 2(1,18 x 10-2)  4,25 × 10 −2  = 2,36 x 10-2 mol·dm-3 = 1,18 x 10-2 mol·dm-3 pH = -log[H 3 O+]  c(H+) = 2c a = -log(2,36 x 10-2)  = 2(1,18 x 10-2)  = 1,63  = 2,36 x 10-2 mol·dm-3 pH = -log[H 3 O+]  = -log (2,36 x 10-2)  = 1,63  (7) OPTION 3/OPSIE 3 n a(excess/oormaat) = cV  = (0,1)(0,005)  = 5 x 10-4 mol + n(H ) = 2n a(excess/oormaat) = 2(5 x 10-4)  = 1 x 10-3 mol n c(H+) = V 1× 10 −3 = 4,25 × 10 −2 = 2,36 x 10-2 mol·dm-3 pH = -log[H 3 O+]  = -log (2,36 x 10-2)  = 1,63  [17] Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 13 DBE/2018 SCE/SSE – Marking Guidelines/Nasienriglyne QUESTION 8/VRAAG 8 8.1 8.1.1 Galvanic (cell)/Voltaic (cell)  Galvaniese (sel)/Voltaïese (sel) (1) 8.1.2 Indicates phase boundary./Interphase /phase separator Dui faseskeiding aan/Interfase /fase onderskeier (1) 8.1.3 Fe2+ → Fe3+ + e-  Notes/Aantekeninge • Fe3+ + e- ← Fe2+ (2 ) Fe3+ + e- ⇌ Fe2+ (0 ) 2 2 Fe ⇌ Fe + e 2+ 3+ - ( 1 ) 3+ - Fe + e → Fe 2+ ( 0 ) 2 2 • Ignore if charge on electron is omitted./Ignoreer indien lading op elektron uitgelaat is. • If a charge of an ion is omitted e.g. Fe2 → Fe3 + e-/Indien lading op ioon uitgelaat is bv. Fe2 → Fe3 + e- Max./Maks: 1 (2) 2 8.1.4 OPTION/OPSIE 1 Notes/Aantekeninge θ E cell θ = E reduction θ − E oxidation  • Accept any other correct formula from the data sheet./Aanvaar enige ander korrekte formule 0,03  = EθX / X2+ - (0,77)  vanaf gegewensblad. EθX / X2+ = 0,80 (V)  • Any other formula using unconventional abbreviations, e.g. Eθ cell = Eθ OA - Eθ RA followed by correct substitutions:/Enige ander formule wat X = Silver / Ag  onkonvensionele afkortings gebruik bv. Eθ sel = Eθ OM - Eθ RM gevolg deur korrekte vervangings: Max/Maks: 4 5 OPTION/OPSIE 2  X+(aq) + e-  X(s) 0,80 (V)  Fe2+(s)  Fe3+(aq) + e- 0,77 (V)  X+(aq) + Fe2+(aq)  X(s) +Fe3+(aq) 0,03 (V)  X = Silver/Ag/Silwer  (5) 8.2 8.2.1 Pt  (1) 8.2.2 Iron(III) (ions)Ferric ions Yster(III)-(ione)/Ferri ione (1) 8.2.3 2Fe3+ + Cu → 2Fe2+ + Cu2+  Bal.  Notes/Aantekeninge • Reactants  Products  Balancing  Reaktanse Produkte Balansering • Ignore phases./Ignoreer fases. • Ignore double arrows./Ignoreer dubbelpyle. • Marking rule 6.3.10/Nasienreël 6.3.10. (3) [14] Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 14 DBE/2018 SCE/SSE – Marking Guidelines/Nasienriglyne QUESTION 9/VRAAG 9 9.1 9.1.1 Electrolyte/Elektroliet  (1) 9.1.2 Conduct electricity/Carry charges  Gelei elektrisiteit/Dra ladings. (1) 9.2 Cu(NO 3 ) 2  (1) 9.3 Iron rod/Ysterstaaf  - Reduction takes place./Reduksie vind plaas.  (2) 9.4 Cu → Cu2+ + 2e-  Notes/Aantekeninge • Cu2+ + 2e- ← Cu (2 ) Cu2+ + 2e- ⇌ Cu (0 ) 2 2 2+ Cu ⇌ Cu + 2e - ( 1 ) 2+ Cu + 2e → Cu ( 0 ) 2 2 • Ignore if charge on electron is omitted./Ignoreer indien lading op elektron uitgelaat is. • If a charge of an ion is omitted e.g. Cu → Cu2 + 2e-/Indien lading op ioon uitgelaat is bv. Cu → Cu2 + 2e- Max./Maks: 1 (2) 2 9.5 9.5.1 Copper(II) (ions)/Cu2+ and silver (ions)/Ag+  Koper(II)-(ione) /Cu2+ en silwer-(ione) /Ag+ Accept/Aanvaar Cu (ions) and Ag (ions) (Ions are stated in the question.) Cu(-ione) en Ag(-ione) (Ione word in vraag genoem.) (2) 9.5.2 Ag+/silver(I) ions is a stronger oxidising agent  than Cu2+/Copper(II) ions and will be reduced (more readily)  to form silver/Ag on the iron rod. Ag+/silwer(I) ione is ‘n sterker oksideermiddel as Cu2+/Copper(II) ione en sal (meer geredelik) gereduseer word om silwer/Ag op die ysterstaaf te vorm. (2 ) [11] Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 15 DBE/2018 SCE/SSE – Marking Guidelines/Nasienriglyne QUESTION 10/VRAAG 10 10.1 10.1.1 (Catalytic) oxidation (of ammonia)/(Katalitiese) oksidasie (van ammoniak) (1) 10.1.2 Neutralisation/acid-base reaction  Neutralisasie/suur-basisreaksie (1) 10.2 10.2.1 Nitrogen/N 2 /Stikstof  (1) 10.2.2 NO 2 /nitrogen dioxide/Stikstofdioksied  (1) 10.2.3 Nitric acid/HNO 3 /Salpetersuur  (1) 10.3 10.3.1 2NH 3 + H 2 SO 4  → (NH 4 ) 2 SO 4  Bal.  Notes/Aantekeninge: • Reactants  Products  Balancing  Reaktanse Produkte Balansering • Ignore double arrows./Ignoreer dubbelpyle. • Marking rule 6.3.10./Nasienreël 6.3.10. (3) 10.3.2 4NH 3 + 5O 2  → 4NO + 6H 2 O  Bal.  Notes / Aantekeninge: • Reactants  Products  Balancing  Reaktanse Produkte Balansering • Ignore double arrows./Ignoreer dubbelpyle. • Marking rule 6.3.10./Nasienreël 6.3.10. (3) 10.4 28  %N= × 100 80  = 35%  (3) [14] TOTAL/TOTAAL: 150 Copyright reserved/Kopiereg voorbehou