Physical Sciences Grade 12 Paper 2 Limpopo Mock 2018 Memo

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE NASIONALE SENIOR SERTIFIKAAT GRADE/GRAAD 12 PHYSICAL SCIENCES: CHEMISTRY (P2) FISIESE WETENSKAPPE: CHEMIE (V2) SEPTEMBER 2018 MEMORANDUM MARKS/PUNTE: 150 This memorandum consists of 11 pages. Hierdie memorandum bestaan uit 11 bladsye. Copyright reserved Please turn over

Downloaded from hlayiso.com 2 Physical Sciences P2/Fisiese Wetenskappe V2 Limpopo September 2018 NSC/NSS - Memorandum QUESTION 1/VRAAG 1 1.1 A  (2) 1.2 A  (2) 1.3 B  (2) 1.4 D  (2) 1.5 B  (2) 1.6 D  (2) 1.7 C  (2) 1.8 A  (2) 1.9 C  (2) 1.10 C  (2) [20] Copyright reserved Please turn over

Downloaded from hlayiso.com 3 Physical Sciences P2/Fisiese Wetenskappe V2 Limpopo September 2018 NSC/NSS - Memorandum QUESTION 2/VRAAG 2 2.1.1 Carboxylic acids //karboksielsure (1) 2.1.2 Molecules with the same molecular formulae but different structural formula // Organiese molekule met dieselfde molekulêre formule, maar verskillende (2) struktuurformules.  2.1.3 Marking criteria/Nasienriglyne: H O H  Whole structure correct/Hele struktuur I II I korrek. 2 H-C – C – O - C-H 2 I I  Functional group correct./Funksionele H H groep korrek. 1 2 (2) 2.1.4 H H O  H HH H  H H H H O H H   I I II I I I I I I I I II I I H–C–C–C–O–H + H–C–C–C–C–O-H  H–C–C–C–C–O–C–C–C-H + H-O-H I I I I I I I I I I I I H H H H H H H H H H H H (4) Notes/Aantekeninge:  Condensed or semistructural formula: Max. 3 4 Gekondenseerde of semistruktuurformule: Maks. 3 4  Molecular formula/Molekulêre formule: 1 4  Marking rule 3.9/Nasienreël 3.9  Any additional reactants or products: Max. 3 4 Enige addisionele reaktanse of produkte: Maks. 4 4  If arrow in equation omitted: Max. 3 4 Indien pyltjie in vergelyking uitgelaat is: Maks. 3 4 2.1.5 Butyl propanoate // butielpropanoaat (2) 2.2 2,4 – dimethyl pent-2-ene (2-pentene) //2,4-dimetielpent-2-een (2) [13] Copyright reserved Please turn over

Downloaded from hlayiso.com 4 Physical Sciences P2/Fisiese Wetenskappe V2 Limpopo September 2018 NSC/NSS - Memorandum QUESTION 3/VRAAG 3 3.1 Temperature at which the vapour pressure of the substance equals atmospheric pressure. Die temperatuur waar die dampdruk van die stof gelyk is aan die atmosferiese druk. (2) 3.2.1 Liquid //vloeistof (1) 3.2.2 Boiling points increase(as chain length increases)  // Kookpunte neem toe(soos die kettinglengte toeneem) (1) 3.2.3 Lower.  The isomer is branched/ rounder/ molecules further away from each other // Laer. Die isomeer is vertak/ ronder/ molekules verder van mekaar (2) 3.3 Alkanes have London forces between molecules, alcohols have hydrogen bonding forces  hydrogen bonding forces are stronger than London forces hydrogen bonding forces more energy is needed to overcome the intermolecular forces between alcohol molecules / break the hydrogen bonding forces hydrogen bonding forces and therefore the boiling point is higher Tussen die alkane kom Londonkragte voor en tussen die alkohole waterstofbindings. Waterstofbindings is sterker as Londonkragte. Dit vereis dus meer energie om die waterstofbindings te breek en daarom is die kookpunt hoër. (3) 3.4.1 The pressure exerted by a vapour in equilibrium with its liquidin a closed system Die druk uitgeoefen deur ‘n damp in ewewig met sy vloeistof in ‘n geslote sisteem Note/aantekening: Allocate mark for closed system only if first part of definition is correct. Ken punt toe vir geslote sisteem slegs indien eerste deel van definisie korrek is. (2) 3.4.2 Lower //Laer  (1) 3.5 H I H H -C- H I I  H - C - C - O - H (2 or/of 0) I I H H -C- H I H (2) [14] Copyright reserved Please turn over

Downloaded from hlayiso.com 5 Physical Sciences P2/Fisiese Wetenskappe V2 Limpopo September 2018 NSC/NSS - Memorandum QUESTION 4/VRAAG 4 4.1.1 The solutionldecolourises/ loses its colour //Die broomwater ontkleur (1) 4.1.2 Halogenation // Halogenering / halogenasie (1) 4.2.1 H H H H H ı ı ı ı ı H – C = C – C – C – C – H + H- Br   ı ı ı H H H H H H H H ı ı ı ı ı H–C-C–C–C–C–H  ı ı ı ı ı H Br H H H (3) 4.2.2 2-bromopentane // 2-bromo pentaan  (2) 4.2.3 Concentrated NaOH/strong base and high temperature/strong heat  (3) Gekonsentreerde  NaOH/KOH/sterk basis, en hoë temperatuur /sterk verhit 4.3 H2SO4 / H3PO4  (1) 4.4.1 Hydrogen  //Waterstof (1) 4.4.2 2C4H10 + 13O2 8CO2 + 10H2O  (bal ) (3) 4.4.3 Exothermic //eksotermies (1) [16] Copyright reserved Please turn over

Downloaded from hlayiso.com 6 Physical Sciences P2/Fisiese Wetenskappe V2 Limpopo September 2018 NSC/NSS - Memorandum QUESTION 5/VRAAG 5 5.1.1 Homogeneous (reaction) //Homogene (reaksie) (1) 5.1.2 Heat of reaction / enthalpy difference / energy difference between products and (1) reactants/ energy products – energy reactants Reaksiewarmte/energieverandering tussen reaktamore particleste en produkte  5.1.3 Iron/iron oxide /Yster / Ysteroksied (1) 5.2 Increase in concentration of N2 means more particles/molecules per unit volume More particles have enough kinetic energy/ energy equal or greater than activation energy Number of effective collisions per unit time increases Verhoging in konsentrasie van N2 beteken meer deeltjies per eenheidvolume. Meer deeltjies het voldoende/genoeg kinetiese energie Die aantal effektiewe botsings per tydseenheid neem dus toe/ frekwensie van effektiewe botsings neem toe. (3) 5.3.1 B. When temperature is increased, according to Le Chatelier the endothermic reaction will be favoured, thus the reverse reaction Yield of ammonia decreases Die voorwaartse reaksie is eksotermies en volgens Le Chatelier sal ‘n temperatuurverhoging teengewerk word deur die endotemiese reaksie bevoordeel wat in hierdie geval die terugwaartse reaksie is. Opbrengs (4) ammoniak verminder dus. 5.3.2 A  (2) 5.3.3 C. (2) [14] Copyright reserved Please turn over

Downloaded from hlayiso.com 7 Physical Sciences P2/Fisiese Wetenskappe V2 Limpopo September 2018 NSC/NSS - Memorandum QUESTION 6/VRAAG 6 6.1.1 A catalyst is a chemical substance which increases the rate of a reaction without undergoing a permanent change itself // ʼn Katalisator is ʼn chemiese stof wat die tempo van ʼn chemiese reaksie verhoog  sonder om self ʼn permanente verandering te ondergaan.  OR/OF A catalyst increases the rate of a reaction by providing an alternative route with lower activation energy. // ʼn Katalisator verhoog die tempo van ‘n reaksie deur ‘n alternatiewe roete  van laer aktiveringsenergie te verskaf. (2) 6.1.2 The reaction is exothermic and releases energy //Die reaksie is (2) eksotermies en stel energie vry. 6.1.3 When pressure is increased the reaction which produces less moles of gas / smaller volume of gas will be favoured  Thus forward reaction is favoured and more NO2 is produced/formed  //As die druk verhoog sal die reaksie wat minder mol gas/kleiner volume gas produseer bevoordeel word  dus sal die voorwaartse reaksie bevoordeel word. (3) Meer NO2 sal dus vorm. Copyright reserved Please turn over

Downloaded from hlayiso.com 8 Physical Sciences P2/Fisiese Wetenskappe V2 Limpopo September 2018 NSC/NSS - Memorandum 6.2.1 NO2(g) + NO(g) ⇌ N2O(g) + O2(g) Initial mol 0,06 0,29 0,18 0,38  aanvanklike mol Used/formed 0,12-0,06 0,06 0,06 0,06 Verbruik/gevorm =0,06   Equilibrium 0,12 0,35 0,12 0,32 (mol∙dm-3) /Ewewig(mol∙dm-3) Add// optel  subtract// aftrek  [ ]  Kc = = = 0,914  [ ]  Marking criteria/nasienriglyne a. initial concentrations/ aanvanklike konsentrasies neer b. Calculate concentration of NO2 used (0,06)/Bereken konsentrasie van NO2 wat gebruik is(0,06) c. Values of other reactants and products used or formed/ Waardes van ander reaktante wat verbruik of gevorm is d. Equilibrium values for reactants/ Ewewig waardes vir reaktante e. Equilibrium values for products/ Ewewig waardes vir produkte f. Correct Kc expression/ Korrekte Kc uitdrukking g. Substitution of concentration in correct Kc expression/ Vervanging van konsentrasies in korrekte Kc-uitdrukking h. Correct final answer/Korrekte finale antwoord (9) 6.2.2 Temperature is decreased // Temperatuuris verlaag (2) [18] Copyright reserved Please turn over

Downloaded from hlayiso.com 9 Physical Sciences P2/Fisiese Wetenskappe V2 Limpopo September 2018 NSC/NSS - Memorandum QUESTION 7/VRAAG 7 7.1.1 Basic// basies  (1) 7.1.2 pH = -log[H3O+]  = - log 10-8 = 8  2 marks for only answer / 2 punte vir slegs antwoord (2) 7.1.3 CO32- + H2O ⇌ HCO3- + OH-  (2) 7.2.1 n(NaOH) = cV = 0,2 mol∙dm-3 x 0,025 dm3 = 0,005 mol NaOH  n(HCl) = cV = 0,15 mol∙dm-3 x 0,04 dm3 = 0,006 mol HCl  1 mol NaOH reacts with //reageer met 1 mol HCl  ∴ Excess//oormaat HCl = 0,006 – 0,005 = 0,001 mol  (7) 7.2.2 Positive marking from 7.2.1// positiewe nasien vanaf 7.2.1 n [H3O+] = = = 0,0154 mol∙dm-3  pH = -log[H3O+]  = -log(0,0154) = 1,812  (5) [17] Copyright reserved Please turn over

Downloaded from hlayiso.com 10 Physical Sciences P2/Fisiese Wetenskappe V2 Limpopo September 2018 NSC/NSS - Memorandum QUESTION 8/VRAAG 8 8.1.1 Temperature 25°C (298 K)  // temperatuur 25°C;  (298 K) Pressure 101,3 kPa (1 atm)  // druk 101,3 kPa (1 atm);  (3) Concentration 1mol∙dm-3 // konsentrasie 1mol∙dm-3  8.1.2 Fe/Fe2+ or/of Fe-half cell/halfsel or/of Fe(s) (2) 8.1.3 Fe  Fe2+ + 2e-  (2) 8.1.4 O2 + 4H+ + 4e-  2H2O  (2) 8.1.5 Fe(s) / Fe2+ (aq) // O2 (g) / H2O (l),Pt(s) ( -1 if // not there) (3) 8.1.6 Eθcell/sel = Eθcathode/katode - Eθanode  Accept any other correct formula from the data = 1,23 - (-0,44) = 1,67 V  sheet / Aanvaar enige ander korrekte formule vanaf gegewensblad.  Any other formula using unconventional abbreviations, e.g. Eθcell = EθOA- EθRA followed by correct substitutions:/ Enige ander formule wat onkonvensionele afkortings gebruik bv. Eθsel = EθOM- EθRM gevolg deur regte vervangings: Max/maks 3/4 (4) 8.2 Mg is a stronger reducing agent than Fe  Therefore Mg is more easily oxidised than iron and prevent that Fe is oxidized to Fe2+.  Mg is ‘n sterker reduseermiddel as Fe. Mg is daarom makliker geoksideer as yster  en verhoed dat Fe na Fe2+ oksideer.  (3) [19] Copyright reserved Please turn over

Downloaded from hlayiso.com QUESTION 9/VRAAG 9 9.1 P (1) 9.2 2H2O + 2e-  H2 + 2OH-  (2) Notes/Aantekeninge  Reactants  Products  Balancing  Reaktanse Produkte Balansering  Ignore double arrows./Ignoreer dubbele pyle. Marking rule 6.3.10./Nasienreël 6.3.10. Marking criteria 9.3 Q na P  (1) 9.4 Water / hygrogen ion // water/ waterstofioon  (1) 9.5 H2  Cl2  NaOH  (any 2 // enige 2) (2) [7] QUESTION 10/VRAAG 10 10.1.1 Fractional distillation of liquid air // Fraksionele distillasie van vloeibare lug  (1) 10.1.2 Contact process / Kontakproses  (1) 10.1.3 2NH3 + H2SO4  (NH4)2SO4  (for/vir bal) (3) 10.2.1 Ratio of nitrogen to phosphorous to potassium t (2) 10.2.2 : x x 50 = 5 kg OR/OF % N: x 30% = 10% Mass of nitogen // massa stikstof: 10% van totale massa van 50 kg ∴: x 50 = 5 kg  (3) 10.2.3 % filler/ vulsel= 100 – 30 = 70% 70 x 50 = 35 kg 100 OR/OF 30 Mass of fertilizer/massa kunsmis = x 50 = 15 100 (2) Mass of filler/massa vulsel = 50 – 15x = 35 kgx [12] TOTAL/TOTAAL: 150 Copyright reserved