Physical Sciences Grade 12 Paper 2 NSC November 2012 Memo

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE NASIONALE SENIOR SERTIFIKAAT GRADE/GRAAD 12 PHYSICAL SCIENCES: CHEMISTRY (P2) FISIESE WETENSKAPPE: CHEMIE (V2) NOVEMBER 2012 MEMORANDUM MARKS/PUNTE: 150 This memorandum consists of 11 pages. Hierdie memorandum bestaan uit 11 bladsye. Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 2 DBE/November 2012 NSC/NSS – Memorandum SECTION A/AFDELING A QUESTION 1/VRAAG 1 1.1 Ketones/Ketone  (1) 1.2 Ethene/Eteen  (1) 1.3 Activation (energy)/Aktiverings(energie)  (1) 1.4 Catalyst/katalistor  (1) 1.5 (saturated) sodium chloride solution  (versadigde) natriumchloried oplossing (1) [5] QUESTION 2/VRAAG 2 2.1 B  (2) 2.2 C  (2) 2.3 A  (2) 2.4 A  (2) 2.5 D  (2) 2.6 D  (2) 2.7 B  (2) 2.8 C  (2) 2.9 D  (2) 2.10 A  (2) [20] TOTAL SECTION A/TOTAAL AFDELING A: 25 Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 3 DBE/November 2012 NSC/NSS – Memorandum SECTION B/AFDELING B QUESTION 3/VRAAG 3 3.1 3.1.1 A (1) 3.1.2 D & F  (2) 3.1.3 D (1) 3.1.4 E (1) 3.1.5 B (1) 3.2 3.2.1 2-methylbut-1-ene  2-metielbut-1-een  (2) 3.2.2 H H H H O H C C C C C O H  H H H H (2) 3.3 3.3.1 Pleasant odour  Aangename geur (1) 3.3.2 Ethanol  Etanol (2) 3.3.3 Ethyl propanoate  Etielpropanoaat (2) [15] QUESTION 4/VRAAG 4 4.1 4.1.1 Fuels  Brandstowwe  (1) 4.1.2 C n H 2n + 2  (1) 4.2 4.2.1 Boiling point/Kookpunt  (1) 4.2.2 Chain length/Molecular size/Molecular mass  Kettinglengte/Molekulêre grootte/Molekulêre massa (1) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 4 DBE/November 2012 NSC/NSS – Memorandum 4.2.3 Criteria for conclusion/Kriteria vir gevolgtrekking: Mark/Punt Dependent and independent variables correctly identified.  Afhanklike en onafhanklike veranderlikes korrek geïdentifiseer. Relationship between the independent and dependent variables correctly stated.  Verwantskap tussen die afhanklike en onafhanklike veranderlikes korrek genoem. Examples/Voorbeelde: • Boiling point increases with increase in chain length/molecular size/molecular mass. Kookpunt neem toe met toename in kettinglengte/molekulêre grootte/molekulêre massa. • Boiling point decreases with decrease in chain length/ molecular size/molecular mass. Kookpunt neem af met afname in kettinglengte/molekulêre grootte/molekulêre massa. • Boiling point is proportional to chain length/molecular size/molecular mass. Kookpunt is eweredig aan kettinglengte/molekulêre grootte/molekulêre massa . (2) 4.3 Pentane/Pentaan  OR/OF Hexane/Heksaan  (1) 4.4 C 3 H 8 + 5O 2 → 3CO 2 + 4H 2 O  bal  (3) 4.5 Lower than  • Structure: Isomers have more branching/ more compact or spherical molecules / smaller surface areas over which the intermolecular forces act.  • Intermolecular forces: Weaker intermolecular forces/less intermolecular forces  • Energy: Less energy needed to overcome intermolecular forces.  Kleiner as  • Struktuur: Isomere meer vertak/Molekule meer kompak of sferies./ Kleiner oppervlaktes waaroor intermolekulêre kragte werk.  • Intermolekulêre kragte Swakker intermolekulêre kragte/ minder intermolekulêre kragte  • Energie: Die minder energie benodig om intermolekulêre kragte te oorkom.  (4) [14] Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 5 DBE/November 2012 NSC/NSS – Memorandum QUESTION 5/VRAAG 5 5.1 5.1.1 Haloalkanes /Haloalkane  (1) 5.1.2 H H C H H H H H C C C C H  H Br H H (2) 5.2 5.2.1 Substitution/Substitusie  OR/OF Hydrolysis/Hidrolise  (1) 5.2.2 H H C H H H H H C C C C H  H O H H H (2) 5.3 5.3.1 Heat strongly  Verhit sterk (1) 5.3.2 Elimination/dehydrohalogenation/dehydrobromination  Eliminasie/dehidrohalogenering/dehidrobrominering  (1) 5.3.3 H H C H H H H H C C C C H  H H (2) 5.4 2-methylbut-2-ene  2-metielbut-2-een (2) [12] Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 6 DBE/November 2012 NSC/NSS – Memorandum QUESTION 6/VRAAG 6 6.1 Carbon dioxide  Koolstofdioksied/koolsuurgas (1) 6.2 6.2.1 (6 ; 3,1)  (1) 6.2.2 12 minutes/minute  (1) 6.2.3. 4 minutes/minute  (1) 6.3 More particles per unit volume  More effective collisions per unit time/second.  Meer deeltjies per eenheids volume deeltjies. Meer effektiewe botsings per eenheids tyd/sekonde. (2) 6.4 6.4.1 Increases/Vermeerder  (1) 6.4.2 Remains the same/Bly dieselfde  (1) 6.4.3 Decreases/Neem af  (1) 6.5 • Add a catalyst/Voeg 'n katalisator by  • Increase surface area of calcium carbonate./Use calcium carbonate powder./Crush calcium carbonate chips.  Verhoog die oppervlakarea van kalsiumkarbonaat./Gebruik kalsiumkarbonaatpoeier./Maak die kalsiumkarbonaatstukkies fyn. (2) 6.6 m n(CO 2 ) =  M 4 = 44  = 0,09 mol n(CaCO 3 ) = n(CO 2 ) = 0,09 mol m(CaCO 3 ) = nM = (0,09) (100)  (5) =9g [16] Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 7 DBE/November 2012 NSC/NSS – Memorandum QUESTION 7/VRAAG 7 7.1 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 is gelyk aan die tempo van die terugwaarste reaksie.  (2) 7.2 n(B)reacted/gereageer = 6 – 4 = 2 mol  n(C)formed/gevorm = n(B)reacted/gereageer = 2 mol  n 2 c(C) = =  = 0,4 mol·dm-3 V 5 (3) 7.3 Increases  • 3 mol/volumes (of gas) produces 2 mol/volumes (of gas)./The reaction which produces the smaller number of moles/volume is favoured.  • Forward reaction is favoured.  Vermeerder  • 3 mol/volumes (gas) produseer 2 mol/volumes (gas)./Die reaksie wat die kleiner getal mol /volume vorm, word bevoordeel. • Voorwaartse reaksie word bevoordeel. (3) 7.4 OPTION 1/OPSIE 1 Use x as the total initial amount of B(g) that must be used. Gebruik x as die totale aanvanklike hoeveelheid B(g) wat gebruik moet word. A B C Initial quantity (mol) 3 x 0 Aanvangshoeveelheid (mol) Change (mol) ratio  -2 -4 +4 Verandering (mol) verhouding Quantity at equilibrium (mol)/ 1 x–4  4 Hoeveelheid by ewewig (mol) Equilibrium concentration (mol∙dm-3) 1 x−4 Ewewigskonsentrasie (mol∙dm-3) = 0,2 0,8 5 5 [C] 2 KC =  Divide by/gedeel deur 5  [ A ][B] 2 (0,8)2 ∴ 0,625  =  No KC expression, correct substitution/Geen Kc- x−4 2 (0,2)( ) 5 uitdrukking, korrekte substitusie: Max./Maks. 8 9 ∴ x = 15,3 mol Wrong KC expression/Verkeerde Kc-uitdrukking: Max./Maks. 6 ∴ n(B) added = 15,3 – 6  9 = 9,3 (mol)  Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 8 DBE/November 2012 NSC/NSS – Memorandum OPTION 2/OPSIE 2 Use x as amount to be added to the amount of B(g) present initially i.e. 6 mol of B(g). Gebruik x as die hoeveelheid wat by die hoeveelheid van B(g) wat aanvanklik teenwoordig was gevoeg moet word d.i. 6 mol B(g). A B C Initial quantity (mol) 0 3 x+6 Aanvangshoeveelheid (mol) Change (mol) ratio  -2 -4 +4 verhouding Verandering (mol) Quantity at equilibrium (mol)/ 1 x+2  4 Hoeveelheid by ewewig (mol) Equilibrium concentration (mol∙dm-3) 1 x+2 Ewewigskonsentrasie (mol∙dm-3) = 0,2 0,8 5 5 [C] 2 KC =  [ A ][B] 2 Divide by/gedeel deur 5  (0,8)2 ∴ 0,625  =  x+2 2 (0,2)( ) 5 ∴x = 9,31 (mol)  OPTION 3/OPSIE 3 Use x as amount to be added to the amount of B(g) present after first equilibrium was established i.e. 4 mol of B(g). Gebruik x as die hoeveelheid wat by die hoeveelheid van B(g) wat teenwoordig is nadat die eerste ewewig ingestel is, gevoeg moet word d.i. 4 mol B(g). A B C Initial quantity (mol) 2 x+4 2 Aanvangshoeveelheid (mol) Change (mol) +2 ratio  -1 -2 Verandering (mol) verhouding Quantity at equilibrium (mol)/ 1 x+2  4 Hoeveelheid by ewewig (mol) Equilibrium concentration (mol∙dm-3) 1 x+2 Ewewigskonsentrasie (mol∙dm-3) = 0,2 0,8 5 5 [C] 2 KC =  [ A ][B] 2 Divide by /gedeel deur 5 2 (0,8) ∴ 0,625  =  x+2 2 (0,2)( ) 5 ∴ x = 9,31 (mol)  (9) [17] Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 9 DBE/November 2012 NSC/NSS – Memorandum QUESTION 8/VRAAG 8 8.1 8.1.1 Increases  The reaction is exothermic./Energy (or heat) is released /ΔH < 0. Vermeerder Die reaksie is eksotermies./Energie (of hitte) word vrygestel/ΔH < 0. (2) 8.1.2 Aluminium is a strong reducing agent/stronger reducing agent  than copper and will reduce the copper(II) ions to copper.  Aluminium is 'n sterk reduseermiddel / sterker reduseermiddel  as koper en sal die koper(II)-ione reduseer na koper.  (2) 8.1.3 2Aℓ(s) + 3Cu2+(aq)→ 2Aℓ3+(aq) + 3Cu(s) bal.  (3) 8.2 8.2.1 Aℓ/Aluminium  (1)    8.2.2 Aℓ(s) | Aℓ3+(1 mol∙dm-3) || Cu2+(1 mol∙dm-3) | Cu(s) (3) 8.2.3 Eo cell = Eo cathode – Eo anode  = 0,34 - (-1, 66)  o E cell = 2,(00)V  (4) 8.2.4 0 (V)/zero/nul  The circuit is open.  Die stroombaan is oop (2) [17] Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 10 DBE/November 2012 NSC/NSS – Memorandum QUESTION 9/VRAAG 9 9.1 Electrical energy to chemical energy.  Elektriese energie na chemiese energie  (1) 9.2 The polarity of the electrodes must remain constant during plating.  Die polariteit van die elektrodes moet konstant bly tydens elektroplatering. (1) 9.3 Reduction/Reduksie  (1) 9.4 9.4.1 Ag → Ag+ + e-  (2) 9.4.2 Silver nitrate/Silwernitraat/AgNO 3  OR/OF Silver ethanoate/silver acetate/Silweretanoaat/silwerasetaat  CH 3 COOAg/AgC 2 H 3 O 2 /AgCH 3 CO 2 (1) 9.5 Rate of oxidation is equal to the rate of reduction.  Tempo van oksidasie is gelyk aan die tempo van reduksie. (2) 9.6 Protection/Beskerming Protects it from rusting / corrosion./Beskerm dit teen roes/korrosie.  OR/OF Appearance/Voorkoms Improve appearance of spoons. / Verbeter voorkoms van die lepels. (1) 9.7 Cost of electricity/ Koste van elektrisiteit.  Cost of silver/ Koste van silwer  (2) [11] QUESTION 10/VRAAG 10 10.1 Primary (cells)/Primêre (selle)  (1) 10.2 (Equation/Vergelyking) 2  Reduction takes place (at the cathode)./Reduksie vind (by die katode) plaas. (2) 10.3 ANY ONE/ENIGE EEN: • The cell reaction reaches equilibrium.  Die selreaksie bereik ewewig.  • The rates of the forward and reverse reactions become equal.  Die tempo van die voorwaartse en terugwaartse reaksies is gelyk.  • Substances reach their equilibrium concentrations.  Stowwe bereik hul ewewigskonsentrasies. (1) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 11 DBE/November 2012 NSC/NSS – Memorandum 10.4 10.4.1 W = qV  ∴ 3 x 104 = q(1,5)  ∴ q = 2 x 104 (C) 2 × 10 4 Cell capacity/Selkapasiteit =  = 5,56 A∙h  3600 (4) 10.4.2 OPTION 1 / OPSIE 1 OPTION 2 / OPSIE 2 q = I∆t  q = I∆t  ∴2 x 104 = I(20)(3600)  ∴5,56 = I(20)  ∴I = 0,28 A  ∴I = 0,28 A  (3) [11] QUESTION 11/VRAAG 11 11.1 11.1.1 Fractional distillation (of liquid air)  Fraksionele distillasie (van vloeibare lug)  (1) 11.1.2 N 2 + 3H 2 ⇌ 2NH 3  bal.  (3) 11.1.3 Contact (process)/Kontak(proses)  (1) 11.1.4 H 2 SO 4 + 2NH 3 → (NH 4 ) 2 SO 4  bal.  (3) 11.1.5 Neutralisation/Acid-base reaction  Neutralisasie/Suur-basisreaksie  (1) 11.2 11.2.1 Nitric acid/HNO 3 / hydrogen nitrate /salpetersuur/ waterstofnitraat  (1) 11.2.2 • Contains (a high percentage of) nitrogen/N/primary nutrient.  Bevat ('n hoë persentasie) stikstof/N/primêre voedingstof. (2) • High solubility /Hoë oplosbaarheid  [12] TOTAL SECTION B/TOTAAL AFDELING B: 125 GRAND TOTAL/GROOTTOTAAL: 150 Copyright reserved/Kopiereg voorbehou