Physical Sciences Grade 12 Paper 2 NSC November 2013 Memo

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE NASIONALE SENIOR SERTIFIKAAT GRADE/GRAAD 12 PHYSICAL SCIENCES: CHEMISTRY (P2) FISIESE WETENSKAPPE: CHEMIE (V2) NOVEMBER 2013 MEMORANDUM MARKS/PUNTE: 150 This memorandum consists of 15 pages. Hierdie memorandum 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/November 2013 NSC/NSS – Memorandum SECTION A/AFDELING A QUESTION 1/VRAAG 1 1.1 Fractional distillation / Fraksionele distillasie  (1) 1.2 Dehydration / Dehidratering / Dehidrasie  (1) 1.3 Collision (theory) / Botsings(teorie)  (1) 1.4 Reducing agent / Reduseermiddel  (1) 1.5 Homologous series / Homoloë reeks  (1) [5] QUESTION 2/VRAAG 2 2.1 C  (2) 2.2 C  (2) 2.3 A  (2) 2.4 D  (2) 2.5 B  (2) 2.6 C  (2) 2.7 A  (2) 2.8 D  (2) 2.9 B  (2) 2.10 C  (2) [20] TOTAL SECTION/TOTAAL AFDELING A: 25 Copyright reserved/Kopiereg voorbehou

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 3 DBE/November 2013 NSC/NSS – Memorandum SECTION B/AFDELING B QUESTION 3/VRAAG 3 3.1 3.1.1 A C (2) 3.1.2 B (1) 3.1.3 F (1) 3.1.4 F  (2) 3.2 3.2.1 4,5-dimethylhex-2-ene  / 4,5-dimetielheks-2-een  OR/OF 4,5-dimethyl-2-hexene  / 4,5-dimetiel-2-hekseen  (2) 3.2.2 2,3-dibromo-5-methylheptane  / 2,3-dibromo-5-metielheptaan  (2) 3.2.3 4-methylpent-2-yne  / 4-metielpent-2-yn OR/OF 4-methyl-2-pentyne  / 4-metielpent-2-yn (2) 3.3 3.3.1 Esters  (1) 3.3.2 H H H H H O H H H C C C C C O C C C H  H H H H H H H (2) 3.3.3 Propanoic acid / Propanoësuur  (1) 3.3.4 Sulphuric acid / Swawelsuur / H 2 SO 4  (1) [17] Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 4 DBE/November 2013 NSC/NSS – Memorandum QUESTION 4/VRAAG 4 4.1 4.1.1 Samples / Contents of bottle / (Type of) compound / functional group / homologous series  Monsters / Inhoud van bottel / (Tipe) verbinding / funksionele groep / homoloë reeks (1) 4.1.2 Boiling point / Kookpunt  (1) 4.2 ... comparable molecular mass. / ... vergelykbare molekulêre massa.  OR/OF ... under the same conditions ... / ... onder dieselfde toestande ... (1) 4.3 4.3.1 Q (1) 4.3.2 R (1) - 4.3.3 • R has the highest boiling point. / R het die hoogste kookpunt.  • In addition to weak Van der Waals forces, alcohols also have strong hydrogen bonds between molecules.  Bo en behalwe swak Van der Waalskragte, het alkohole ook sterk waterstofbindings tussen molekule. (2) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 5 DBE/November 2013 NSC/NSS – Memorandum 4.4 Higher than  - • Structure: Longer chain length. / More C atoms in chain. / Greater molecular size. / Greater molecular mass. / Larger surface area.  • Intermolecular forces: Stronger or more intermolecular forces /Van der Waals forces / dispersion forces / London forces.  • Energy: More energy needed to overcome or break intermolecular forces/ Van der . Waals forces / dispersion forces / London forces. Hoër as - • Struktuur: Langer kettinglengte. / Meer C-atome in kettting. / Groter molekule. / Groter molekulêre massa. / Groter reaksieoppervlakte. • Intermolekulêre kragte: Sterker of meer intermolekulêre kragte/ Van der Waalskragte / dispersiekragte / Londonkragte. • Energie: Meer energie benodig om intermolekulêre kragte/ Van der Waalskragte/ dispersiekragte / Londonkragte te oorkom of breek. OR/OF Higher than  - • Structure: Pentane has a shorter chain length. / Less C atoms in chain. / Smaller molecular size. / Smaller molecular mass. / Smaller surface area.  • Intermolecular forces: Weaker or less intermolecular forces / Van der Waals forces / dispersion forces / London forces.  • Energy: Less energy needed to overcome or break intermolecular forces / Van der Waals forces / dispersion forces / London forces.  Hoër as - • Struktuur: Pentaan het 'n korter kettinglengte. / Minder C-atome in kettting. / Kleiner molekule. / Kleiner molekulêre massa. / Kleiner reaksieoppervlakte. • Intermolekulêre kragte: Swakker of minder intermolekulêre kragte/ Van der Waalskragte/ dispersiekragte / Londonkragte . • Energie: Minder energie benodig om intermolekulêre kragte/Van der Waalskragte / dispersiekragte / Londonkragte te oorkom of breek. (4) [11] Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 6 DBE/November 2013 NSC/NSS – Memorandum QUESTION 5/VRAAG 5 5.1 Alkenes / Alkene  (1) 5.2 5.2.1 C 4 H 10 + Cℓ 2  → C 4 H 9 Cℓ + HCℓ  Bal.  (3) 5.2.2 Halogenation / Substitution / Chlorination  Halogenering / Halogenasie / Substitusie / Chlorinering (1) 5.2.3 Heat OR (sun)light (UV) / hf  Hitte OF (son)lig (UV) / hf (1) 5.3 5.3.1 H H H H H C C C C H  H Br Br H (2) 5.3.2 But-2-ene / 2-butene  But-2-een / 2-buteen (2) 5.3.3 H H H H H H H H    H C C C C H + H2 H C C C C H H H H H H H (4) 5.3.4 Hydrogenation / Addition  Hidrogenering / Hidrogenasie / Addisie (1) [15] Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 7 DBE/November 2013 NSC/NSS – Memorandum QUESTION 6/VRAAG 6 6.1 6.1.1 (Type of) catalyst / (Tipe) katalisator  (1) 6.1.2 Rate (of reaction) / (Reaksie)tempo  (1) 6.2 R - Fastest rate. / Steepest (initial) gradient or slope. /Produces oxygen faster/est / reaches completion faster OR fastest OR in a shorter time  Vinnigste tempo. / Steilste (aanvanklike) gradiënt of helling./ Produseer suurstof vinnigste/er/ bereik voltooiing vinnigste OF vinniger OF in 'n korter tyd. (2) 6.3 • A catalyst provides an alternative pathway of lower activation energy.  'n Katalisator voorsien 'n alternatiewe pad van laer aktiveringsenergie. • More molecules have sufficient/enough kinetic energy. / Meer molekule het voldoende/genoeg kinetiese energie.  OR/OF More molecules have kinetic energy equal to or greater than the activation energy. Meer molekule het kinetiese energie gelyk aan of groter as die aktiveringsenergie. • More effective collisions per unit time./ Rate of effective collisions increases. Meer effektiewe botsings per eenheidstyd./ Tempo van effektiewe botsings neem toe. / (3) 6.4 Δ[H2 O 2 ] Average rate/Gemiddelde tempo = Δt 0,0131 - 0,020  = 400 - (0)  = - 1,73 x 10-5 mol∙dm-3∙s-1  OR/OF 1,73 x 10-5 mol∙dm-3∙s-1 (3) 6.5 Less than / Kleiner as  - The concentration of hydrogen peroxide decreases as the reaction proceeds.  Die konsentrasie van die waterstofperoksied verminder soos wat die reaksie verloop. (2) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 8 DBE/November 2013 NSC/NSS – Memorandum 6.6 Mark allocation/Puntetoekenning: n m m • c= or/of n = or/of c =  V M MV • Substitute / Vervang (0,0200 - 0,0106) and/en 50 x 10-3  • n(O 2 ) = ½n(H 2 O 2 )  • Using/Gebruik M = 32 in m = nM or/of cMV or/of a ratio calculation / ‘n verhouding berekening  • Final answer/Finale antwoord: 7,52 x 10-3 g / 0,008 g / 0,01 g OPTION 1/OPSIE 1 OPTION 2/OPSIE 2 n c=  ∆c(H 2 O 2 ) = 0,0200 – 0,0106 V n = 0,0094 (0,0200 - 0,0106) =  50 × 10 − 3 ∆c(O 2 ) = ½∆c(H 2 O 2 ) ∴ n = 4,7 x 10-4 mol = ½(0,0094)  = 0,0047  n(O 2 ) = ½n(H 2 O 2 ) = ½(4,7 x 10-4)  = 2,35 x 10-4 mol m c=  m MV n(O 2 ) = M ∆m(O 2 ) = cMV -4 m = (0,0047)(32)  (50 x 10-3) 2,35 x 10 =  32 = 7,52 x 10-3 g -3 ∴ m(O 2 ) = 7,52 x 10 g = 0,008 g = (0,008 g) = (0,01 g)  = 0,01g (5) [17] Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 9 DBE/November 2013 NSC/NSS – Memorandum QUESTION 7/VRAAG 7 7.1 Low / Laag  - Small K c value. / Klein K c -waarde.  K c is smaller than 1/ K c is kleiner as 1 (2) 7.2 CALCULATIONS USING NUMBER OF MOLES: BEREKENINGE WAT GETAL MOL GEBRUIK: Mark allocation/Puntetoekenning: • USING ratio/GEBRUIK verhouding: N 2 : O 2 : NO = x : x : 2x  • Equilibrium/Ewewig: n(N 2 ) = initial/aanvanklik – change/verandering Equilibrium/Ewewig: n(O 2 ) = initial/aanvanklik – change/verandering  • Equilibrium/Ewewig: n(NO) = initial/aanvanklik + change/verandering • Divide n(N 2 ), n(O 2 ) & n(NO) by 5 dm3.  Deel n(N 2 ), n(O 2 ) & n(NO) deur 5 dm3. • Correct K c expression (formulae in square brackets).  Korrekte K c -uitdrukking (formules in vierkanthakies). • Substitution of concentrations into K c expression.  Vervanging van konsentrasies in K c -uitdrukking. • Substitution of K c value.  Vervanging van K c -waarde . -3 -3 -3 • Final answer/Finale antwoord: 4,36 x 10 mol·dm  (0,004 mol·dm ) OPTION 1/OPSIE 1 N2 O2 NO Initial quantity (mol) 2 2 0 Aanvangshoeveelheid (mol) Change (mol) ratio  x x 2x Verandering (mol) Quantity at equilibrium (mol) 2-x 2-x  2x  Hoeveelheid by ewewig (mol) Equilibrium concentration (mol∙dm-3) 2-x 2-x 2x Ewewigskonsentrasie (mol∙dm-3) Divide by 5  5 5 5 2  2x  2   [NO] -4  5  0,4 2 KC =  ∴ 1,2 x 10  =  [N2 ][O 2 ]  2 − x  2 − x  0,2 2     5  5  ∴ x = 0,0109 mol 2(0,0109 ) ∴ [NO] = = 4,36 x 10-3 mol∙dm-3  (0,004 mol∙dm-3) 5 Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 10 DBE/November 2013 NSC/NSS – Memorandum OPTION 2/OPSIE 2 N2 O2 NO Initial quantity (mol) 2 2 0 Aanvangshoeveelheid (mol) Change (mol) x x Verandering (mol) x ratio  2 2 Quantity at equilibrium (mol) x x Hoeveelheid by ewewig (mol) 2- 2-  x 2 2 Equilibrium concentration (mol∙dm-3) 4-x 4-x x Ewewigskonsentrasie (mol∙dm-3) Divide by 5  10 10 5 [NO] 2 KC =  [N2 ][O 2 ] 2 x   -4 ∴ 1,2 x 10  = 5   4 − x  4 − x      10  10  ∴ x = 0,022 mol 0,022 ∴ [NO] = = 4,36 x 10-3 mol∙dm-3  (0,004 mol∙dm-3) 5 OPTION 3/OPSIE 3 N2 O2 NO Initial quantity (mol) 2 2 0 Aanvangshoeveelheid (mol) Change (mol) 5x 5x Verandering (mol) 5x 2 2 ratio  Quantity at equilibrium (mol) 5x 5x Hoeveelheid by ewewig (mol) 2- 2-  5x  2 2 Equilibrium concentration / 4 - 5x 4 - 5x Ewewigskonsentrasie 10 x Divide by (mol∙dm-3) 10 5 [NO] 2 KC =  [N2 ][O 2 ] ∴ 1,2 x 10-4  = (x )2   4 − 5 x  4 − 5 x      10  10  ∴ x = 4,36 x 10-3 mol∙dm-3  (0,004 mol∙dm-3) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 11 DBE/November 2013 NSC/NSS – Memorandum CALCULATIONS USING CONCENTRATIONS BEREKENINGE WAT KONSENTRASIES GEBRUIK Mark allocation/Puntetoekenning • Divide n(N 2 ) & n(O 2 ) by 5 dm3.  Deel n(N 2 ) & n(O 2 ) deur 5 dm3. • USING ratio/GEBRUIK verhouding: N 2 : O 2 : NO = 1 : 1 : 2  • Equilibrium/Ewewig: c(N 2 ) = initial/aanvanklik – change/verandering Equilibrium/Ewewig: c(O 2 ) = initial/aanvanklik – change/verandering  Equilibrium/Ewewig: c(NO) = initial/aanvanklik + change/verandering • Correct K c expression (formulae in square brackets).  Korrekte K c -uitdrukking (formules in vierkanthakies). • Substitution of concentrations into K c expression.  Vervanging van konsentrasies in K c -uitdrukking. • Substitution of K c value  Vervanging van K c -waarde • Calculate c(NO) i.e. 2 x answer of K c calculation.  Bereken c(NO) d.i. 2 x antwoord van K c -berekening. • Final answer/Finale antwoord: 4,36 x 10-3 mol·dm-3  (0,004 mol·dm-3) OPTION 3/OPSIE 3 N2 O2 NO Initial concentration (mol∙dm-3) 0,4 0,4 0 Divide by 5  Aanvangskonsentrasie (mol∙dm-3) Change (mol∙dm-3) ratio  x x 2x Verandering (mol∙dm-3) Equilibrium concentration (mol∙dm-3) 0,4-x 0,4-x  2x Ewewigskonsentrasie (mol∙dm-3) [NO] 2 KC =  [N2 ][O 2 ] 2 (2x )2 ∴ 1,2 x 10-4  =  (0,4 - x )(0,4 - x ) ∴ x = 2,18 x 10-3 mol∙dm-3 (0,00218 mol∙dm-3) ∴ [NO] = 2(2,18 x 10-3) = 4,36 x 10-3 mol∙dm-3  (0,004 mol∙dm-3) (8) 7.3 7.3.1 Remains the same / Bly dieselfde  (1) 7.3.2 Remains the same / Bly dieselfde  (1) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 12 DBE/November 2013 NSC/NSS – Memorandum 7.4 Endothermic / Endotermies  - • (An increase in K C implies) an increase in concentration of products.  ('n Toename in K c impliseer)'n toename in die konsentrasie van produkte. OR/OF (An increase in K C implies) that the forward reaction is favoured. ('n Toename in K c impliseer) dat die voorwaartse reaksie bevoordeel is. OR/OF (3) (An increase in K C implies) the equilibrium position shifts to the right. [15] ('n Toename in K c impliseer) dat die ewewigsposisie na regs geskuif het. • An increase in temperature favours an endothermic reaction.  'n Toename in temperatuur bevoordeel die endotermiese reaksie. QUESTION 8/VRAAG 8 8.1 8.1.1 Au3+ / gold(III) ion  Au3+ / goud(III)-ioon (1) 8.1.2 2Cℓ- → Cℓ 2 + 2e-  Notes/Aantekeninge 2Cℓ- ⇌ Cℓ 2 + 2e- (1 ) 2 - 2Cℓ ← Cℓ 2 + 2e - (0 ) 2 - Cℓ 2 + 2e ← 2Cℓ - ( 2 ) 2 Cℓ 2 + 2e- ⇌ 2Cℓ- ( 0 ) (2) 2    8.1.3 Pt(s) | Cℓ- (1 mol·dm-3) | Cℓ 2 (g) || Au3+(1 mol·dm-3) | Au(s) OR/OF Pt(s) | Cℓ-(aq) | Cℓ 2 (g) || Au3+ (aq) | Au(s) OR/OF Pt | Cℓ- | Cℓ 2 || Au3+ | Au (3) 8.2 Option 1/Opsie 1 Eo cell = Eo cathode – Eo anode  0,14  = Eo cathode - (1, 36)  Eo cathode = 1,50 V  Option 2/Opsie 2 2Cℓ- → Cℓ 2 + 2e- E° = - 1,36   Au3+ + 3e- → Au E° = +1,50  E° = 0,14 V  (4) 8.3 Smaller than / Kleiner as  - Decrease or drop in potential difference or voltage due to internal resistance or ”lost volts”.  Val of afname in potensiaalverskil of spanning as gevolg van interne weerstand of “velore volts”. (2) [12] Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 13 DBE/November 2013 NSC/NSS – Memorandum QUESTION 9/VRAAG 9 9.1 The chemical process in which electrical energy is converted to chemical energy. Die chemiese proses waarin elektriese energie omgeskakel word na chemiese energie. OR/OF The use of electrical energy to produce chemical change.  Die gebruik van elektriese energie om chemiese verandering te weeg te bring. (2) 9.2 9.2.1 Cr3+ + 3e-→ Cr(s)  (2) 9.2.2 Cr / chromium / chroom  (1) 9.2.3 Chromium(III) ions / chroom(III)-ione / Cr3+  (1) 9.3 Mark allocation/Puntetoekenning: m • n= or using ratio / of gebruik van verhouding  M • Ratio: 1 : 3 (1 mole Cr3+ gains 3 mole of electrons)  Verhouding 1: 3 (1 mol Cr3+ neem 3 mol elektrone op) • Using M = 52 in m = nM or in ratio calculation.  Gebruik M = 52 in m = nM of verhouding berekening . • Final answer/Finale antwoord: 0,52 g  m n=  M  0,03  m m   =  OR/OF 0,01 =   3  52 52 ∴ m = 0,52 g  OR/OF 3 mol e- ........ 52 g  Cr  0,03  0,03 mol e-.......    (52)  = 0,52 g   3  (4) [10] Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 14 DBE/November 2013 NSC/NSS – Memorandum QUESTION 10/VRAAG 10 10.1 A solution which conducts electricty through the movement of ions.  'n Oplossing wat elektrisiteit gelei deur die beweging van ione. (2) 10.2 Pb(s) + SO 4 2-(aq) → PbSO 4 (s) + 2e-  (2) 10.3 PbO 2 (s) + Pb(s) + 2SO 4 2-(aq) + 4H+(aq) → 2PbSO 4 (s) + 2H 2 O(ℓ)  bal.  OR/OF PbO 2 (s) + Pb(s) + 2H 2 SO 4 (aq) → 2PbSO 4 (s) + 2H 2 O(ℓ)  bal.  (3) 10.4 10.4.1 OPTION 1/OPSIE 1 OPTION 2/OPSIE 2 Q = IΔt W = VIΔt  = (7 500)  (3 600)  = (300) (7500)  (3600)  = 2,7x107 C = 8,1 x 109 J  W = VQ  = (300)  ( 2,7x107) = 8,1 x 109 J  (5) 10.4.2 Eθ cell = Eθ cathode – Eθ anode  = +1,69 - (-0,36)  = +2,05 V 300 No. cells =  2,05 = 146,34 cells/selle ∴ 147 cells / selle  (5) [17] Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P2/Fisiese Wetenskappe V2 15 DBE/November 2013 NSC/NSS – Memorandum QUESTION 11/VRAAG 11 11.1 11.1.1 Phosphorous / Fosfor / P  (1) 11.1.2 Nitrogen / Stikstof / N  (1) 11.1.3 Potassium / Kalium / K  (1) 11.2 11.2.1 Haber (process)/(proses)  (1) 11.2.2 N 2 (g) + 3H 2 (g)  ⇌ 2NH 3 (g)  bal.  (3) 11.3 The fertiliser contains two primary nutrients N/nitrogen and P/ phosphorous,  whereas the ammonium nitrate contains only N/nitrogen.  Die kunsmis bevat twee primêre nutriente N en P terwyl ammoniumnitraat slegs N bevat. (2) 11.4 ANY ONE /ENIGE EEN • Fertilisers in water leads to eutrophication which can result in less drinking water / starvation due to dying of fish / less water recreation areas.  Kunsmis in water lei tot eutrofisering / eutrofikasie wat minder drinkwater // hongersnood weens visvrektes /minder ontspanningsgebiede tot gevolg kan hê. • Fertilisers in water leads to excess of nitrates in water  resulting in blue baby syndrome / cancer.  Kunsmis in water lei tot oormaat nitrate in water wat lei tot bloubabasindroom / kanker. (2) [11] TOTAL SECTION B/TOTAAL AFDELING B: 125 GRAND TOTAL/GROOTTOTAAL: 150 Copyright reserved/Kopiereg voorbehou