Gr 11 Physical Sciences P2 (ENG & AFR) 2023 Possible Answers_hlayiso.com_.pdf

Downloaded from hlayiso.com PROVINCIAL EXAMINATION/ PROVINSIALE EKSAMEN NOVEMBER 2023 GRADE/GRAAD 11 MARKING GUIDELINES/NASIENRIGLYNE PHYSICAL SCIENCES: CHEMISTRY/ FISIESE WETENSKAPPE: CHEMIE PAPER/VRAESTEL 2 9 pages/bladsye P.T.O./ B.O.

Downloaded from hlayiso.com PHYSICAL SCIENCES: CHEMISTRY MARKING GUIDELINES/ FISIESE WETENSKAPPE: CHEMIE NASIENRIGLYNE PAPER/VRAESTEL 2 GRADE/GRAAD 11 QUESTION/VRAAG1 1.1 C ✓✓ (2) 1.2 B ✓✓ (2) 1.3 D ✓✓ (2) 1.4 A ✓✓ (2) 1.5 C ✓✓ (2) 1.6 A ✓✓ (2) 1.7 C ✓✓ (2) 1.8 D ✓✓ (2) 1.9 B ✓✓ (2) 1.10 B ✓✓ (2) [20] QUESTION/VRAAG 2 2.1 2.1.1. ✓✓ (2) 2.1.2. ✓✓ Without brackets only 1 mark/ (2) ✓✓ Sonder hakies slegs 1 punt 2.2. A covalent bond is a bond in which electron pairs are shared between the two atoms to form a molecule. ✓✓ ʼn Kovalente binding is ʼn binding waar elektronpare gedeel word tussen twee atome om ʼn molekule te vorm. ✓✓ (2) 2.3 Calcium/Ca ✓ Kalsium/Ca ✓ (1) 2.4 The bond between positive ions and delocalised valence electrons in a metal. ✓✓ ʼn Binding tussen positiewe ione en gedelokaliseerde elektrone in ʼn metaal.✓✓ (2) 2

Downloaded from hlayiso.com PHYSICAL SCIENCES: CHEMISTRY MARKING GUIDELINES/ FISIESE WETENSKAPPE: CHEMIE NASIENRIGLYNE PAPER/VRAESTEL 2 GRADE/GRAAD 11 2.5 2.5.1 CO2/carbon dioxide ✓ CO2/koolstofdioksied ✓ (1) 2.5.2 CaO ✓ (1) 2.6 Electronegativity is a measure of the tendency of an atom in a molecule to attract bonding electrons. ✓✓ Elektronegatiwiteit is die maatstaf van die neiging van ʼn atoom in ʼn molekuul om bindingselektrone aan te trek. ✓✓ (2) 2.7 ΔEN = 3,5 – 1 = 2,5 ✓ ∴ Ionic bond ✓/Ioniese binding✓ (2) 2.8 Non-polar molecule ✓/Nie-polêre molekule ✓ (1) 2.9 ΔEN = 3.5 – 2,5 = 1,0 ∴ polar bond ✓/ ∴ polêre binding ✓ But shape is symmetrical thus the molecule is polar ✓/Maar die vorm is simmetries en dus is die molekule polêr. ✓ (2) [18] QUESTION/VRAAG 3 3.1 The temperature at which the vapour pressure of a substance equals atmospheric pressure. ✓✓ Die temperatuur waarby die dampdruk van ʼn stof gelyk is aan die atmosferiese druk. ✓✓ (2) 3.2 3.2.1 London/dispersion forces ✓ London/dispersiekragte ✓ (1) 3.2.2 I2 ✓ (1) 3.2.3 As the molecular mass increases, ✓ the strength of the intermolecular forces increases ✓ Therefore more energy is needed to overcome/weaken the intermolecular forces. ✓ (no mark if BROKEN is used instead of overcome or weaken) Thus the boiling boiling point increases. ✓✓ Indien die molekulêre massa toeneem, ✓ word die sterkte van die intermolekulêre kragte groter. ✓✓ Meer energie word benodig om die intermolekulêre kragte te oorkom/te verswak. ✓ (geen punte indien GEBREEK in plaas van oorkom gebruik word nie.) (3) 3

Downloaded from hlayiso.com PHYSICAL SCIENCES: CHEMISTRY MARKING GUIDELINES/ FISIESE WETENSKAPPE: CHEMIE NASIENRIGLYNE PAPER/VRAESTEL 2 GRADE/GRAAD 11 3.3 3.3.1 NH3/ammonium ✓ NH3/ammoniak ✓ (1) 3.3.2 HCℓ/hydrogen chloride ✓ HCℓ/waterstofchloried ✓ (1) [9] QUESTION/VRAAG 4 4.1 What is the relationship between the pressure and volume of an enclosed mass of gas, when the temperature is kept constant? ✓✓ Wat is die verband tussen die druk en volume van ʼn ingeslote massa gas, indien die temperatuur konstant gehou word. ✓✓ (2) 4.2.1 Pressure ✓ Druk ✓ (1) 4.2.2 Temperature/mass of gas ✓ Temperatuur/massa van gas ✓ (1) 4.3 Boyle’s Law.✓ The pressure of an enclosed gas is inversely proportional to the volume it occupies at a constant temperature ✓✓ Boyle se wet. ✓ Die druk van ʼn ingeslote gas is omgekeerd eweredig aan die volume van die gas by ʼn konstante temperatuur. ✓✓ (3) 4.4 OPTION/OPSIE 1 OPTION/OPSIE 2 p1V1 = p2V2 ✓ p1V1 = p2V2 ✓ (200)(16,5) = (110)X ✓ (150)(1,65x 10-2) = (110)X ✓ X = 30 cm3 ✓ X = 3 x 10-2 dm3 ✓ (3) 4.5 At low temperatures, a real gas’s particles will occupy space and have volume. ✓✓ By lae temperature sal ʼn werklike gas se deeltjies spasie inneem en volume besit. ✓✓ OR/OF The attraction and repulsive forces between the particles become significant. ✓✓ Thus, a real gas will liquify at low temperatures. Die aantrekkings- en afstotingskragte tussen deeltjies raak noemenswaardig. ✓✓ Dus sal ʼn werklike gas vervloei by lae temperature. (2) 4.6 pV = nRT ✓ 200 x 103 (50 x 10-6) ✓= n 8,31 (298) ✓ n = 0,00403 mol/4,30 x 10-3 mol ✓ (4) 4.7 The average kinetic energy of the molecules of the gas. ✓✓ Die gemiddelde kinetiese energie van die molekules van die gas. ✓✓ (2) 4

Downloaded from hlayiso.com PHYSICAL SCIENCES: CHEMISTRY MARKING GUIDELINES/ FISIESE WETENSKAPPE: CHEMIE NASIENRIGLYNE PAPER/VRAESTEL 2 GRADE/GRAAD 11 4.8 The volume of the container is constant thus: ✓ As the kinetic energy of the molecules of the gas increases, the number of collisions on the sides of the container increases. ✓ Pressure will increase. ✓ Die volume van die houer is konstant dus: ✓ Soos wat die kinetiese energie van die molekules van die gas toeneem, sal die aantal botsings teen die kante van die houer toeneem. ✓ Die druk sal toeneem. ✓ (3) [21] QUESTION/VRAAG 5 5.1 5.1.1 The simplest ratio in which the elements of the compound are bonded to each other.✓✓ Die eenvoudigste verhouding waarin die elemente van ʼn verbinding aanmekaar gebind is. ✓✓ (2) 5.1.2 O% = 100 – (60,0+ 4,44)  = 35,56% 𝑚 60,0 C: n= 𝑀 = 12 = 5 mol 𝑚 4,44 H: n= 𝑀 = = 4,44 mol 1 𝑚 35,56 O: n= 𝑀 = 16 = 2,22 mol C : H : O 5 4,44 2,22 : :  2,22 2,22 2,22 2,25 : 2 :1 9 : 8 :4 Empirical formula/Empiriese formule: C9H8O4 (6) 5.1.3 M(C9H8O4) = 9(12) + 8(1) + 4(16) = 180 g.mol-1 molar mass/molêre mass 180 = =1  emprical mass/empiriese massa 180 molecular formula/molekulêre formule: C9H8O4 (2) 5.2 M (Na2CO3) = 106g·mol-1 M (x H2O) = 268 – 106  = 162g·mol-1 n(H2O) =m/M =162/18  n(H2O) = 9 mol (4) [14] 5

Downloaded from hlayiso.com PHYSICAL SCIENCES: CHEMISTRY MARKING GUIDELINES/ FISIESE WETENSKAPPE: CHEMIE NASIENRIGLYNE PAPER/VRAESTEL 2 GRADE/GRAAD 11 QUESTION/VRAAG 6 6.1 6.1.1 The limiting reagent is the reactant that is used up first.  Die beperkende reagens is die een wat eerste opgebruik word. ✓✓ (2) 6.1.2 n(KCl) = cV = 0,25 (0,055)  = 0,0138 n(AgNO3) = cV = 0,15(0,07)  = 0,0105 KCℓ : AgNO3 1 : 1  0,0105 : 0,0105 AgNO3 is the limiting reagent/die beperkende reagens  (5) 6.1.3 n(AgCl) = n(AgNO3) = 0,0105 mol  m = nM  = 0,0105(143,5)  = 1,51 g  (4) 𝑚 6.2 6.2.1 n(CaCO3) =  𝑀 50 = 100  = 0,5 mol (3) 6.2.2 𝑚 18,2 n(CO2) = 𝑀 = 44  = 0,414 mol n(CaCO3) = n(CO2) = 0,414 mol  m(CaCO3) = nM = 0,414(100)  = 41,4 g 41,4 % purity/suiwerheid = 50 x 100  = 82,8% (5) m 6.2.3 % purity/suiwerheid = 70% = 50  m = 35 g CaCO3 𝑚 35 n(CaCO3) = 𝑀 = 100  = 0,35 mol n(CO2) = n(CaCO3) = 0,35 mol  m(CO2) = nM = 0,35(44)  = 15,4 g  (5) [24] 6

Downloaded from hlayiso.com PHYSICAL SCIENCES: CHEMISTRY MARKING GUIDELINES/ FISIESE WETENSKAPPE: CHEMIE NASIENRIGLYNE PAPER/VRAESTEL 2 GRADE/GRAAD 11 QUESTION/VRAAG 7 7.1 7.1.1 An acid is a proton (H+ ion) donor.  ʼn Suur is ʼn proton (H+- ioon) skenker. ✓✓ (2) 7.1.2 It ionises to form 2 protons/2 moles of H+ ions. / Dit ioniseer om 2 protone/2 mol H+ ione te vorm. ✓✓ OR/OF It donates 2 H+ ions per H2SO4 molecule.  Dit skenk 2 H+ ione per H2SO4 molekule.  (2) 7.1.3 Ampholyte  Amfoliet  (1) 7.2 7.2.1 A solution of precisely known concentration.  ʼn Oplossing waarvan die konsentraise presies bekend is.  (2) 7.2.2 H2SO4(ℓ) + 2H2O(ℓ) → 2H3O+(aq) + SO2-4 (aq)   (balancing/balansering) (3) 7.3 7.3.1 na c V = c a Va  nb b b 1 c (0,012) a = 0,2 2 (0,02) ca = 0,17 mol.dm-3 (5) 7.3.2 Methyl orange , reaction of strong acid  and strong base . Metieloranje , reaksie van ʼn sterk suur  en ʼn sterk basis.  (3) [18] QUESTION/VRAAG 8 8.1 Endothermic✓ Endotermies  (1) 8.2 The Products have more Potential energy than the reactants. ✓✓ Die produk het meer Potensiële energie as die reaktante.  OR/OF More energy is absorbed than released ✓✓ Meer energie word geabsorbeer as vrygestel. ✓✓ (2) 8.3 + 14,8 kJ.mol-1✓✓ without a + sign only 1 mark/sonder ʼn + teken slegs een punt (2) 8.4 4+6✓ (1) 8.5 the minimum energy needed for a reaction to take place. ✓✓ die minimum energie benodig vir ʼn reaksie om plaas te vind, ✓✓ (2) 7

Downloaded from hlayiso.com PHYSICAL SCIENCES: CHEMISTRY MARKING GUIDELINES/ FISIESE WETENSKAPPE: CHEMIE NASIENRIGLYNE PAPER/VRAESTEL 2 GRADE/GRAAD 11 8.6 3✓ (1) 8.7 It decreases the activation energy, ✓ by providing an alternative pathway for the reaction. ✓ Dit verminder die aktiveringsenergie, ✓ deur ʼn alternatiewe roete vir die reaksie te skep. ✓ (2) NOTE/LET WEL: 8.8 ✓ Dotted line from reactants to products ✓ Stippellyn van reaktante na produkte ✓ Lower that 3 and higher than 4 ✓ Laer as 3 en hoër as 4 Course of the reaction/verloop van die reaksie (2) [13] QUESTION/VRAAG 9 9.1 9.1.1 An increase in the oxidation number.  ʼn Toename in die oksidasiegetal.  (2) 9.1.2 +6  (2) 9.2 9.2.1 Electrons are transferred. / Elektrone word oorgedra.  OR/OF The oxidation number of Fe2+/Cℓ2 changes.  Die oksidasiegetal van Fe2+/Cℓ2 verander.  OR/OF Fe2+ is oxidised/Cℓ2 is reduced.  Fe2+ is geoksideer/Cℓ2 is gereduseer.  (1) 9.2.2 Fe2+ The oxidation number increases from +2 to +3.  Fe2+ Die oksidasiegetal neem toe van +2 na +3.  (2) 9.2.3 Cℓ2 + 2e- → 2Cℓ- (2) 9.2.4 Cℓ2 + 2e- → 2Cℓ-  Fe2+ → Fe3+ + e-  2Fe2+ + Cℓ2 → 2Fe3+ + 2Cℓ- (balancing/balansering) (4) [13] TOTAL/TOTAAL: 150 8

Downloaded from hlayiso.com PHYSICAL SCIENCES: CHEMISTRY MARKING GUIDELINES/ FISIESE WETENSKAPPE: CHEMIE NASIENRIGLYNE PAPER/VRAESTEL 2 GRADE/GRAAD 11 TAXONOMY GRID Recall Comprehension Analysis Evaluation Q no: Mark Q no: Mark Q no: Mark Q no: Mark 1.1 2 1.3 2 1.2 2 1.7 2 1.4 2 1.5 2 1.6 2 1.10 2 1.8 2 1.9 2 2.2 2 2.1.1 2 2.7 2 2.1.2 2 2.9 2 2.3 1 2.4 2 2.6 2 2.5 2 2.8 1 3.1 2 3.2.1 1 3.2.2 1 3.2.3 3 3.3.1 2 4.7 2 4.1 2 4.4 3 4.8 3 4.2 2 4.6 4 4.3 3 4.5 2 5.1.1 2 5.1.2 6 5.2 4 5.1.3 2 6.1.1 2 6.1.2 5 6.1.3 4 6.2.1 3 6.2.2 5 6.2.3 5 7.1.1 2 7.1.2 2 7.3.1 5 7.1.3 1 7.2.1 3 7.2.2 2 7.3.2 3 8.1 1 8.2 2 8.8 2 8.5 2 8.3 2 8.4 1 8.6 1 8.7 2 9.1.1 2 9.1.2 2 9.2.1 1 9.2.2 2 9.2.3 2 9.2.4 4 Actual Total 15% 23 43% 64 37% 56 5% 7 Target Total 15% 15 40% 40 35% 35 10% 10 9