# Physical Sciences Grade 12 P2 KwaZulu Natal Mock 2021 Memo > Grade 12 Physical Sciences Paper 2 memorandum from the KwaZulu Natal Mock Exam 2021, 39 pages. Read online or download the free PDF. - Page: https://www.hlayiso.com/library/physical-science-grade-12-trial-2021-p2-and-memo/9d9902ee-07e1-418c-beef-888dbc075d39 - Updated: 2026-09-27 - Subject: Physical Sciences - Grade: Grade 12 - Document type: Memorandum - Year: 2021 - Exam period: KwaZulu Natal Mock Exam - Paper: 2 - Curriculum: CAPS - Pages: 39 Breadcrumbs: [Home](https://www.hlayiso.com/) › [Library](https://www.hlayiso.com/library) › [Grade 12](https://www.hlayiso.com/library/grade-12) › [Physical Sciences](https://www.hlayiso.com/library/grade-12/physical-sciences) › [Physical Sciences Grade 12 P2 KwaZulu Natal Mock 2021 Memo](https://www.hlayiso.com/library/physical-science-grade-12-trial-2021-p2-and-memo/9d9902ee-07e1-418c-beef-888dbc075d39) ## About this document Physical Sciences · Grade 12 · KwaZulu Natal Mock Exam · 2021. Memorandum, 39 pages. Read online or download the PDF. Read it free online on the page above; download the PDF from there. ## Document text Text extracted from the PDF. Layout, diagrams and tables may not survive extraction. ### Page 1 Downloaded from hlayiso.com SEPTEMBER EXAMINATION 2021 ### Page 2 Physical Sciences/P2 Downloaded from hlayiso.com INSTRUCTIONS AND INFORMATION 1 10. 11. 12. Write your centre number and examination number in the appropriate spaces on the ANSWER BOOK. This question paper consists of TEN questions. Answer ALL the questions in the ANSWER BOOK. Start EACH question on a NEW page in the ANSWER BOOK. Number the answers correctly according to the numbering system used in this question paper. Leave ONE line between two subquestions, e.g. between QUESTION 2.1 and QUESTION 2.2. You may use a non-programmable calculator. You may use appropriate mathematical instruments. Show ALL formulae and substitutions in ALL calculations. Round off your FINAL numerical answers to a minimum of TWO decimal places. Give brief motivations, discussions, etc. where required. You are advised to use the attached DATA SHEETS. Write neatly and legibly. CS UIT AU AA TAAA T ANHT]_ Pease torn over ### Page 3 Downloaded from hlayiso.com Physical Sciences/P2 3. SC/NSC QUESTION 1: MULTIPLE-CHOICE QUESTIONS Four options are provided as possible answers to the following questions. Choose the answer and write only the letter (A-D) next to the question numbers (1.1 to 1.10) in the ANSWER BOOK, e.g. 1.11 E. 4.1 Which ONE of the following is an ALKANE? A CeHs B CeHi0 C CeHi2 D = CoHia (2) 1.2 Esters are formed by a reaction between two organic compounds, X and Y, each with a different functional group. The functional groups of these compounds are: Compound X Compound Y A Hydroxyl group Carboxyl group B Hydroxyl group Carbonyl group Cc Hydroxide ion Carboxyl group D Hydroxide ion Carbonyl group (2) 1.3 When butane is subjected to high temperatures and pressures, the following reaction takes place: Butane — methane + Y Which ONE of the following represents Y? A CHCCH3 B CH2CHCH3 C CH3CH2CH3 D CH3CHCHCH3 (2) | i | Copyright reserved CANO A A Please turn over KWAZULU-NATAL ### Page 4 Downloaded from hlayiso.com Physical Sciences/P? 1.4 A hydrochloric acid solution, HC£(aq), of concentration 1 mol-dm® is added to EXCESS POWDERED magnesium at 25 °C. Curve I below represents the volume of hydrogen gas produced during the reaction. Curve II was obtained at different conditions using the SAME VOLUME of hydrochloric acid solution. A IL Pig Volume of hydrogen gas produced Nn Time Which ONE of the following represents the conditions used to obtain curve II? 1.5 STATE OF DIVISION aa elles TEMPERATURE OF Mg 3 (°C) (mol-dm~) A | Ribbon 0,5 25 B | Ribbon 2 25 C | Powder 1 20 D | Powder 1 30 (2) In which ONE of the following reactions at equilibrium will the YIELD of the product increase when the VOLUME of the container is increased at constant temperature? A Nz204(g) = 2NO2(g) B HA(g) + lag) = 2HIQ) C No(g) + 3H2(g) = 2NH3(g) D =. 2S0,(g) + O2(g) = 280s(g) (2) Copyright reserved Please turn over KWAZULU-NATAL, ### Page 5 Downloaded from hlayiso.com Physical Sciences/P2 5 SCINSC 1.6 Which ONE of the following statements is TRUE for an EXOTHERMIC reaction? A More energy is absorbed than released. B More energy is released than absorbed. C Heat of reaction (AH) is positive. D Energy of the products is greater than the energy of the reactants. (2) 1.7 Consider the equation below. HaPOx(aq) + H20(t) = H3O"(aq) + H2PO; (aq) Which ONE of the following is a conjugate acid-base pair? A _H30*(aq) and H20(£) B — H3PO,(aq) and H20(£) C — H3PO,(aq) and H30*(aq) D —_H30*(aq) and H2PO; (aq) (2) 1.8 Consider the balanced equation for the reaction below: 2Cr*(aq) + Sn**(aq) > 2Cr**(aq) + Sn?*(aq) The OXIDISING AGENT is: A B Cc D Cr“(aq) Cr**(aq) Sn**(aq) Sn*(aq) (2) Conyrh reseed MUA AMINGN IN| 5224 over ### Page 6 Physical Sciences/P2 Downloaded from hlayiso.com 1.9 An electrochemical cell is set up at standard conditions. The cell notation for the cell is given below. Mg(s) | Mg**(aq) || Pb*(aq) | Pb(s) The cell is now connected in a circuit. Which ONE of the graphs below BEST represents the concentrations of the electrolytes after a long time? As B 4 5 $ Pb**(aq) & é a | _Pb*(aq) i g Mg™*(aq) 8 5 Fi = 2 Mg**(aq) °o [S) . oO . Time (s) Time (s) Cc D A * i z Mg”*(aq) 3 Mg?*(aq) = oO fo} El/ — S 6 % 1 5 1 = = 3 Pb?*(a 8 8 7 8 Pb”*(aq) : Time (s) Time (s) (2) 1.10 Two 50 kg bags, containing fertilisers R and S respectively, are labelled as follows: Fertiliser R: 3: 1:5 (20) Fertiliser S: 1:2: 6 (20) \dentify the fertiliser(s) most suitable for healthy leaf growth and healthy root growth. LEAF GROWTH ROOT GROWTH A R R B cS} R Cc R S) D Ss iS) (2) [20] Copyimreseves NTNU NATAMININL UI) ——Fe2s2 mover ### Page 7 Physical Sciences/P2 Downloaded from hlayiso.com SOnsc QUESTION 2 (Start on a new page.) The letters A to E in the table below represent five organic compounds. 2.1 2.2 2.3 Cony veseres AUN MIAN | =552 ove A Bk H3 CH2CH3 aoe ae 2 | oxy, H i le CH2CH3 Boe 8 oe ped d i ft D | CH3(CH2)2CH(OH)CH2CH3 fii | CH3CH2CH2CH2CH2CH2CHCH2 Write down the LETTER that represents EACH of the following: faa A ketone 2.1.2 A hydrocarbon 2.1.3 An alkene Write down the: 2.2.1 IUPAC name of compound A 222 STRUCTURAL FORMULA of compound D- 2.2.3 IUPAC name of the STRAIGHT CHAIN FUNCTIONAL ISOMER of compound C Compound B is a straight chain compound that undergoes the following exothermic reaction: 2C,Hy + 2502(g) > 16CO2(g) + 18H20(g) 2.3.1 Besides being exothermic, what type of reaction is represented above? 2.3.2 Determine the MOLECULAR FORMULA of compound B. The reaction above takes place in a closed container at a constant temperature higher than 100 °C and at constant pressure. 2.3.3 Calculate the TOTAL VOLUME of gas formed in the container when 50 cm? of C,Hy reacts completely with oxygen. (1) (1) (3) (2) (3) [16] ### Page 8 Physical Sciences/P2 Downloaded from hlayiso.com QUESTION 3 (Start on a new page.) Compounds A, B and C are used to investigate a factor which influences the boiling points of organic compounds. The results of the investigation are given in the table below. COMPOUND BOILING POINT (°C) A_ | Butan-1-ol 117 B_ | Butan-2-ol 100 C | 2-methylpropan-2-ol 82 3.1 Is this a fair investigation? Choose from YES or NO. 3.2 Give a reason for the answer to QUESTION 3.1. 3.3 Fully explain the difference in the boiling points of compounds B and C. 3.4 Define the term positional isomer. 3.5 From compounds A, B and C, choose the letter(s) that represent(s) EACH of the following: 3.5.1 3.5.2 3.6 The graph below represents the relationship between vapour pressure and Positional isomers A tertiary alcohol Give a reason for the answer. temperature for compound A (butan-1-ol). 3.6.1 3.6.2 Copyright reserved a Vapour pressure (kPa) Temperature (°C) Write down the value of X. Redraw the graph above in the ANSWER BOOK. On the same set of axes, sketch the curve that will be obtained for compound C. Clearly label the curves A and C. Indicate the relevant boiling point for compound C on the graph. KWAZULU-NATAL, Please turn over (1) (1) (3) (2) (1) (2) (1) (2) [13] ### Page 9 Downloaded from hlayiso.com Physical Sciences/P2 9 SC/NSC QUESTION 4 (Start on a new page.) 41 Conyromtreseves INNA IMMUN! P2256 over The flow diagram below shows various organic reactions using propane as starting reactant. R, T and U represent different organic compounds. Compound T is a CARBOXYLIC ACID and compound U is a FUNCTIONAL ISOMER of pentanoic acid. Reaction 1, R Reaction 2 Propane FB ., Dilute NaOH Propan-1-ol T Reaction 3 Write down the NAME of the type of reaction represented by: 4.1.1 Reaction 1 4.1.2 Reaction 2 Consider reaction 1 and reaction 2. 4.1.3 Write down the IUPAC name of compound R. Reaction 3 takes place in the presence of a catalyst and heat. Write down the: 4.1.4 NAME or FORMULA of the catalyst 4.1.5 IUPAC name of compound T 4.1.6 STRUCTURAL FORMULA of compound U (1) (1) (2) (1) (2) (2) ### Page 10 Physical Sciences/P2 4.2 Downloaded from hlayiso.com A laboratory technician wants to prepare but-2-ene using but-1-ene as starting reagent, as shown below. H Cc J | H H coe 2 ————— But-2-ene xI—-oO-Lt H The following chemicals are available in the laboratory: |__concentrated H2SO, __| H20 [__concentrated NaOH __ | Select the chemicals required to design this preparation from the list above. For EACH step of the preparation, write down the balanced equation, using STRUCTURAL FORMULAE for all organic compounds. Indicate the chemicals needed in each step. (6) [15] QUESTION 5 (Start on a new page.) 5.1 5.2 5.3 Study the Maxwell-Boltzmann distribution curve for a certain reaction below. P P and Q are the labels of the axes. What quantity is represented by: 6.1.1 P ~ (1) 5.1.2 Q (1) Line R represents the minimum energy required for the reaction to take place. 5.2.1 Write down the term for the underlined phrase. (1) 5.2.2 How will the shaded area on the graph be affected when a catalyst is added? Choose from INCREASE, DECREASE or REMAINS THE SAME. (1) Use the collision theory to explain how a catalyst influences the rate of reaction. (4) tala! UMC AN a ue ### Page 11 Downloaded fr Physical Sciences/P2 11. SC/NSC om hlayiso.com 1 5.4 The reaction between POWDERED calcium carbonate, CaCO;(s), and EXCESS hydrochloric acid, HCf(aq), is used to investigate reaction rate at 25 °C. The balanced equation for the reaction is: CaCO3(s) + 2HCLf(aq) > CaCta(aq) + H20(£) + CO2(g) Several experiments are conducted using the same mass of IMPURE calcium carbonate and different initial concentrations of dilute hydrochloric acid. The graph below represents the results obtained. Assume that the impurities do not react. 3) gees He FEE EEEE EH HEHE er pa 50—= | 4 s | O° + 4 - S ieee Ly ee & E c 4 iO 40 : a eet Sc H 2c + rH tt: a 30 SE EEEEEEE Z ert ge I : PEE 3 EERE : : 204 zy ® “EEE Ceretels FF + D a - g EPEE “| LH g 10 ei 4 : : : PERE HEE eenteenes Ay easeceses SESEE:! EESEOOOOSCHEGSESSESSSSSCS000% Fat! : 0 0,005 0,01 0,015 0,02 0,025 0,03 0,035 Initial concentration of HC2 (mol-dm> For this investigation, write down a: 5.4.1 Controlled variable 5.4.2 Conclusion ) (1) (2) The CaCOx(s) in 6g of the impure sample reacts completely with 0,03 mol-dm* HC2(aq) in 26 minutes. 5.4.3 Use the information in the graph to calculate the percentage purity of the calcium carbonate. Assume that the molar gas volume at 25 °C is 24 000 cm’. Copyright reserved KWAZULU-NATAL (6) [17] Please turn over ### Page 12 Downloaded from hlayiso.com Physical Sciences/P2 12. QUESTION 6 (Start on a new page.) Steam, H20(g), reacts with hot carbon, C(s), at 1000 °C according to the following balanced equation: 2H20(g) + C(s) = 2H2(g) + CO2(g) Initially, 36 g of steam and a certain amount of carbon were placed in a 2 dm® sealed container and allowed to react. At equilibrium it was found that the amount of carbon changed by 0,225 mol. 6.1 Define the term dynamic equilibrium. 6.2 Calculate the equilibrium constant, K., for the reaction at 1 000 °C. 6.3 The graph shows how the rates of the forward and reverse reactions change with time. —— Forward reaction --- Reverse reaction Rate to th te ts Time 6.3.1 Give a reason why the rate of the forward reaction decreases between ty and t1. 6.3.2 What change was made to the equilibrium mixture at t3? At time tz, the temperature of the system is increased. 6.3.3 Is the forward reaction EXOTHERMIC or ENDOTHERMIC? 6.3.4 Refer to Le Chatelier’s principle to explain the answer to QUESTION 6.3.3. ee UNCUT A AA Please turn over (2) (8) (1) (1) (1) (2) [15] ### Page 13 Downloaded from hlayiso.com Physical Sciences/P2 SC/NSC QUESTION 7 (Start on a new page.) Two beakers, A and B, contain strong bases. Beaker A: 500 cm’ of barium hydroxide, Ba(OH)2(aq) of unknown concentration X Beaker B: 400 cm’ of potassium hydroxide, KOH(aq) of concentration 0,1 mol-dm> 7.1 Define a base according to the Arrhenius theory. (2) 7.2 Calculate the number of moles of hydroxide ions (OH) in beaker B. (2) 7.3 The contents of beakers A and B are added together in beaker C. The solution in beaker C has a pH of 13. Assume that the volumes are additive and that the temperature of the solutions is 25 °C. fo —™ Cc A B i 0,1 mol-dm*® Ba(OH).(aq) | 500 cm pH = 13 400 cm* | KOH(aq) 7.3.1 Calculate the concentration, X, of the Ba(OH), in beaker A. (8) The solution in beaker C is titrated with ethanoic acid. It was found that 15 cm? of the solution neutralises 30 cm’ of the acid. The balanced equation for the reaction is: CH3COOH(aq) + OH"(aq) > CH,COO”(aq) + H20(0) 7.3.2 Is ethanoic acid, CH3COOH(aq), a WEAK acid or a STRONG acid? Give a reason for the answer. (2) 7.3.3 Calculate the concentration of the ethanoic acid. (4) [18] Conyighrecered NINTH INU AITANAUTIN——Fe9s0 tm oe ### Page 14 Downloaded from hlayiso.com QUESTION 8 (Start on a new page.) A galvanic cell at standard conditions is represented by the cell notation below. X and Y are unknown electrodes. X | Zn?*(aq) || Fe**(aq) , Fe**(aq) | Y 8.1 Write down the NAME or FORMULA of: 8.1.1 Electrode X (1) 8.1.2 Electrode Y (1) 8.1.3 The oxidising agent (1) 8.2 Write down: 8.2.1 ONE function of electrode Y (1) 8.2.2 The half-reaction that takes place at electrode Y (2) 8.2.3 The net (overall) equation for the cell reaction that takes place in this cell (3) 8.3 Calculate the initial emf of this cell. (4) 8.4 How will the initial emf of the cell be affected when the concentration of the iron(II) ions is changed to 0,6 mol:dm®? Choose from INCREASES, DECREASES or REMAINS THE SAME. (1) {14} Copyighreseres MNT NTMI Pe =52 rove ### Page 15 Downloaded from hlayiso.com Physical Sciences/P2 SC/NSC QUESTION 9 (Start on a new page.) The simplified diagram below represents an electrochemical cell used for the purification of copper. The impure copper contains small amounts of silver (Ag) and zinc (Zn) as the only impurities. DC source +——Impure copper Electrolyte |}—> 9.1 Define the term electrolysis. (2) 9.2 Write down the NAME or FORMULA of TWO positive ions present in the electrolyte. (2) 9.3 Write down the half-reaction that takes place at the cathode. (2) 9.4 Refer to the Table of Standard Reduction Potentials and explain why the purified copper will NOT contain any zinc. (3) 9.5 Calculate the maximum mass of Cu formed if 0,6 moles of electrons are transferred. (3) [12] Copyrah reseed NANT) 2861 over ### Page 16 Q ip} ___Downloaded from hlayiso.com SC/NSC QUESTION 10 (Start on a new page.) 10.1 10.2 The flow diagram below shows processes involved in the production of fertiliser C. Gas A Haber process H2SO,(aq) || Fertiliser C Compound B H2(g) Write down the NAME or FORMULA of: 10.1.1 Gas A 10.1.2 The catalyst used in the Haber process 10.1.3 Compound B Write down the: 10.1.4 Name of the process used to produce gas A 10.1.5 Balanced equation for the formation of fertiliser C A 40 kg bag of fertiliser contains 65% filler. The mass of the nutrients in the bag is shown in the table below. NUTRIENTS MASS (kg) Nitrogen x Phosphorous 2x Potassium 5 Calculate the NPK ratio of the fertiliser. TOTAL: Mas | NACE A A (1) (1) (1) (1) (3) (3) [10] 150 ### Page 17 Physical sciencese OWNloaded from hlay Iso.com SC/NSC DATA FOR PHYSICAL SCIENCES GRADE 12 PAPER 2 (CHEMISTRY) GEGEWENS VIR FISIESE WETENSKAPPE GRAAD 12 VRAESTEL 2 (CHEMIE) TABLE 1: PHYSICAL CONSTANTS/TABEL 1: FISIESE KONSTANTES NAME/NAAM SYMBOL/S/MBOOL VALUE/WAARDE TABLE 2: FORMULAE/TABEL 2: FORMULES n= n= ar N, n m Vv c=_ orlof c=—— i. Vv MV Vin SoNe Me H = -log[H,0* CV, pH = -log[H30"] Kw = [H30*][OH] = 1 x 10° at/by 298 K Cr) c) @ _fe @ Eee = Ecatnode ~ Enotes /Eset = Ejatote ~ Eanode orlof © _fe 8 6 _fe 8 Een ae E eduction = ES idation/ E ser ee Eredutsie = E oisidasie orlof 6 _ fe @ 6 = ee _ fe Eee = E oidisingagent he See 1 Eee = E orsideenmiidet Ereduseemiddel Copyright reserved Please turn over KWAZULU-NATAL ### Page 18 cal Sciences/P2 2. SC/NSC TABLE 3: THE PERIODIC TABLE OF ELEMENTS TABEL 3: DIE PERIODIEKE TABEL VAN ELEMENTE Phy DBE/November 2020(2) 2 3 4 5 6 7 8 9 10 «11 2 13 # «44 #15 #1 #i& #18 ) (Il) (a (Cd a 0°22) AZ) VLD) oc Atomic number . KEY/SLEUTEL Atoomgetal rf ; . 29 4 ) 3 4 Electronegativity la Cy [Symbol 5 6 7 8 9 10 > Li (2 Be Elektronegatiwiteit "| — re Simbool > 2cCcRmenNneore Ne 7 9 : 14 42) 44|°16| 19 | 20 1 12 i 43) 441945] 46) 47] 18 > Va |S Mg Approximate relative atomic mass “age sils PS ice, Ar 23 24 Benaderde relatiewe atoommassa 27 28 31 32 35,5 40 19 20 21 22] 23 24, 25| 26, 27| 28] 29{/ 30/ 31 32| 33| 34] 35/ 36 > K (2 Cal? Sc /2 Ti [2 © Cr (2 Mn/@ Fe [2 Co|® Ni |2 Cu [2 Zn |2 Ga /2 Ge|& As |S Se|S Br; Kr 39 40 45 48 | 51 521 55| 56/ 59| 59| 635| 65| 70/ 73| 75| 79| 80| 84 37 38 39 40 | 41 ao 4s) ag 45 | 46 | 47 | 4s] 49) 50] 5t 52 | 53 | 54 > We Sr |S * Zr| Nb|2 Mol? Tc |S Ru|s Rh/s Pd 2 Ag |= Cd/= In |2 Snj2 Sb|x Teja | | Xe 86 88 89 91 92 | 96 101; 103; 106] 108] 112} 115| 119] 122| 128| 127| 131 55 56 57 72 | 73 7 75) 76) wi) 78 | 79 | 80) 31 $2) 83 64) 95 | 96 > 33/2 Bal La/@ Hf} Ta| W)| Re| Os| Ir| Pt| Au| Hg/2 Te |2Pb/2 Bi = Pols At) Rn 33| 137] 139| 179] 181] 184] 186} 190] 192} 195| 197] 201| 204| 207} 209 87 88 89 a Fr is Ra Ac 58] 59 | 60 | 61 | 62 | 63 | 64 | 65 | 66 | 67 | 68 |] 69 | 70 | 71 Ce | Pr | Nd | Pm|Smj Eu | Gd| Tb | Dy | Ho| Er | Tm| Yb | Lu 140 | 144 | 144 150 | 152 | 157 | 159 | 163 | 165 | 167 | 169 | 173 | 175 90 91 | 92 | 93 | 94 | 95 | 96 | 97 | 98 | 99 | 100 | 101 | 102 | 103 Th | Pa | U | Np] Pu|Am/|Cm)| Bk | Cf | Es | Fm | Md | No | Lr 232 238 ‘ )pyright reserved IN AA A ll AMI KWAZULU-NATAL Please turn over ### Page 19 Physical Sciences/P ising ability/Toenemende oksiderende vermoé ing oxi Increas. Copyright reserved Downloaded from hlayiso.coy SC/NSC TABLE 4A: STANDARD REDUCTION POTENTIALS TABEL 4A: STANDAARD-REDUKSIEPOTENSIALE Half-reactions/Halfreaksies E® (v) Fo(g)+2e° = 2F + 2,87 a +1,81 H2Q2 + 2H* +267 2H20 +1,77 MnO4 +8H’+5e = Mn™+4H,O | +1,51 Chg) + 2e° 2cr + 1,36 CrO% +14H'+6e" = 2Cr'*+7H20 | + 1,33 O2(g) + 4H*+4e° =) 2H20 + 1,23 MnQ2+ 4H*+2e = -Mn** + 2H20 + 1,23 4 Pt?* + 2e7 Pt + 1,20 Br(t)+2e = 2Br + 1,07 NO; +4H*+3e = NO(g)+2H20 | +0,96 Hg’ +2e = Hg(?) + 0,85 Agte = Ag + 0,80 NO; +2H*+e = NO2(g)+H2O + 0,80 Fe" +e = Fe™* +0,77 O2(g) + 2H*+2e° = -H2O2 + 0,68 k+2e = 2 + 0,54 Cu'te” = Cu + 0,52 SQ2+4H*+4e = S+2H20 + 0,45 2H20+0O2+4e = 40H” +0,40 a + 0,34 SOF +4H*+2e = SO2(g)+2H,O| +0,17 Cu*+e = Cur + 0,16 Sie t2ec = Sno + 0,15 S+2H'+2e = HeS(g) +0,14 2H" +2e° = Ha(g) 0,00 Fe +3e = Fe ~ 0,06 Pb*+2e = Pb - 0,13 Sn*+2e = Sn - 0,14 Nit +2e = Ni - 0,27 Co*+2e = Co - 0,28 Cd*+2e = Cd - 0,40 Cr*+e = Cr 0,41 Fe*+2e = Fe — 0,44 cr'+3e = Cr ~0,74 Zn**+2e = Zn - 0,76 2H20+2e = Hg)+20H | 0,83 ge. - 0,91 Mn**+2e7 = Mn - 1,18 Att +3e7 = AL - 1,66 Mg” +2e° = Mg — 2,36 Na*+e = Na -2,71 Ga, 26; Ga — 2,87 Srt+2e = Sr - 2,89 Ba®* + 2e7 Ba — 2,90 Gs te: = Co - 2,92 Ki +e K - 2,93 tigte: = i — 3,05 KWAZULI UN, i IATAL /November 2020(2) Increasing reducing ability/Toenemende reduserende vermoé Please turn over ### Page 20 Downloaded from hlayiso.com _ SC/INSC TABLE 4B: STANDARD REDUCTION POTENTIALS TABEL 4B: STANDAARD-REDUKSIEPOTENSIALE Half-reactions/Halfreaksies = (Vv) lite = Li — 3,05 K'+e = K - 2,93 e+ 6. = Ge —2,92 Ba’*+2e = Ba - 2,90 Sr*+2e = Sr - 2,89 Ca*+2e = Ca ~ 2,87 Nate” = Na 2,71 Mg’ +2e = Mg — 2,36 Agt*+3e = At -1,66 4 Mn**+2e = Mn -1,18 © Cr'+2e = Cr - 0,91 g 2HO+2e = Ha(g)+20H | -0,83 3 Zn*+2e = Zn - 0,76 g . cr*+3e" a Cr 0,74 iS 3 Fe +2e = Fe -0,44 $ 9 Crete, = Cre -0,41 ® s Cd*+2e = Cd 0,40 7 G (Con +26, = Co - 0,28 eo rs N2*+2e = Ni ~0,27 8 2 Sn?*+2e = Sn = 0,14 3 5 Pb +2e = Pb -0,13 2 5 Fe*+3e = Fe - 0,06 3 g 2H*+2e° = Hag) 0,00 5 8 S+2H'+2e = HS(g) +0,14 £ £ Snt2q, = Sh +0,15 5 = Cu*¥+e = Cur +0,16 2 rs so% +4H*+2e° = SO2(g)+2H20| +0,17 — > Cie £26, = Cu + 0,34 = a 2H20+O2+4e = 40H + 0,40 ry s SQ. +4H*+4e7 = S+2H,0 +0,45 > 3 Cu’+e = Cu + 0,52 oO 2 ee +0,54 3 3 O2(g) + 2H*+2e° = H2Oe +0,68 2 3 Fe"+e = Fe* +0,77 gy S NO} +2H"+e" = NOx(g)+H20 | +0,80 2 2. Ag’'te = Ag +0,80 5 Hg**+2e = Hg(t) + 0,85 £ NO; +4H™+3e = NO(g)+2H20 | +0,96 Bro(t)+2e° = 2Br +1,07 Pi +2e = Pt + 1,20 MnOQo+ 4H*+2e° = Mn** + 2H20 + 1,23 Ox(g)+4H*+4e =) 2H20 +1,23 CO? +14H*+6e° = 2Cr*+7H20 | +1,33 CL(g)+2e = 2cr + 1,36 MnO] +8H*+5e = Mn*+4H,O | +4,54 HeO2+2H*+2e = 2H,0 44,77 Co* +e” = al + 1,81 F.(g)+2e° = + 2,87 iaeaaiaaiiiel UI AN A i INT ### Page 21 Downloaded from hlayiso.com le Fg basic education ca ie Department: \ Basic Education REPUBLIC OF SOUTH AFRICA ERRATAJERRATUM NSC EXAMINATIONS: Preparatory Examinations 2021 NSS-EKSAMEN: Voorbereidende Eksamen 2021 SUBJECT/VAK: PHYSICAL SCIENCES/FISIESE WETENSKAPPE PAPERI/VRAESTEL: 2 DATE OF EXAMINATION: Monday 20 September 2021 DATUM VAN EKSAMEN: Maandag 20 September 2021 SESSIONISESSIE: 1 (09:00--12:00) ATTENTIONIAANDAG: CHIEF INVIGILATOR/HOOFTOESIGHOUER ENGLISH VERSION: ERROR 1 : { Page QUESTION ERROR | CORRECTION L_5 1.10 Incorrect question | Replace with the question below. 1.10 The electrolytic cell illustrated below is used to electroplate a nickel rod with copper. Which ONE of the following is the correct representation of a suitable electrolyte and the nickel rod that should be used in the above cell to obtain the expected results? ELECTROLYTE : NICKEL ROD A NiSOs{aq) X. B CuSOa(aq) X Cc NiSOa4{aq) Y D CuSOa(aq) Y (2) ### Page 22 Downloaded from hlayiso.com ERROR 2 : Page | QUESTION ERROR CORRECTION 15° 10 Incorrect QUESTION 10 © Replace QUESTION 10 with the _ | entire question below. QUESTION 10 (Start on a new page.) Consider the Table of Standard Reduction Potentials below. Half-reactions E® (v) Cr++2e = Cr - 0,91 2H20 +2e- = He(g) + 20H" | -—0,83 Zn*+2e = Zn -0,76 Crt+3e = Cr - 0,74 Fe*+2e = Fe 1 -0,44 Cette = Crt -0,41 Sn +2e = Sr +0,15 Cu2t+e7 = Cut +0,16 Cu +2e = Cu + 0,34 2H20 + O2+4e° = 40H" +0,40 Cui+e = Cu + 0,52 Agt+e = Ag +0,80 02(9)+4H*+4e° = 2H20 +1,23 Ch{gj+2e7 = 2Ct + 1,36 10.1 Define the term reducing agent in terms of electron transfer. 10.2 From the above Table of Standard Reduction Potentials, write down the: 10.2.1 NAME or FORMULA of the strongest reducing agent 10.2.2 Oxidation half-reaction with the lowest oxidation potential 10.2.3 Reduction potential of the half-reaction in which Cr**(aq) acts as reducing agent 10.3 A learner pours a copper(I!) sulphate solution into a zinc container. 10.3.4 Is a zinc container suitable to store a copper(II) sulphate solution? Choose from YES or NO. 10.3.2 Explain the answer to QUESTION 10.3.1 by referring to the above table, (2) (1) (2) (1) (1) (3) [10] ### Page 23 Downloaded from hlayiso.com SENIOR CERTIFICATE/SENIOR SERTIFIKAAT NATIONAL SENIOR CERTIFICATE/ NASIONALE SENIOR SERTIFIKAAT GRADE/GRAAD 12 PHYSICAL SCIENCES: CHEMISTRY (P2) FISIESE WETENSKAPPE: CHEMIE (V2) SEPTEMBER 2021(2) MARKING GUIDELINES/NASIENRIGLYNE MARKS/PUNTE: 150 This memorandum consists of 17 pages. Hierdie memorandum bestaan uit 17 bladsye. Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om assbelief ### Page 24 Downloaded from hlayiso.com Physical Sciences/P2/Fisiese Wetenskappe/V2 2 DBE/September 2021(2) SC/NSC/SS/NSS – Marking Guidelines/Nasienriglyne QUESTION 1/VRAAG 1 1.1 D  (2) 1.2 A  (2) 1.3 B  (2) 1.4 D  (2) 1.5 A  (2) 1.6 B  (2) 1.7 A  (2) 1.8 D  (2) 1.9 C  (2) 1.10 C  (2) [20] Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om assbelief ### Page 25 Downloaded from hlayiso.com Physical Sciences/P2/Fisiese Wetenskappe/V2 3 DBE/September 2021(2) SC/NSC/SS/NSS – Marking Guidelines/Nasienriglyne QUESTION 2/VRAAG 2 2.1 2.1.1 C (1) 2.1.2 B/E  (1) 2.1.3 E (1) 2.2 2.2.1 2-bromo-4-ethyl-3,3-dimethylhexane/2-broom-4-etiel-3,3-dimetielheksaan Marking criteria/Nasienkriteria  Correct stem i.e. hexane./Korrekte stam: heksaan.   All substituents (bromo, ethyl and dimethyl) correctly identified./Alle substituente (broom, etiel en dimetiel) korrek geïdentifiseer.   Substituents correctly numbered, in alphabetical order, hyphens and commas correctly used./Substituente korrek genommer, in alfabetiese volgorde, koppeltekens en kommas korrek gebruik.  (3) 2.2.2 H Marking criteria/Nasienkriteria:   Six carbons in longest chain. H H H O H H Ses koolstowwe in die langste ketting.  H C C C C C C H   Hydroxyl group on third carbon./Hidroksielgroep op H H H H H H tweede koolstof.  Notes/Aantekeninge:  One or more H atoms omitted/Een of meer H-atome uitgelaat: 1 2  Condensed or semi-structural formula:/Gekondenseerde of semi-struktuur- formule: 1 2 (2) 2.2.3 Pentanal / Pentanaal  Marking criteria/Nasienkriteria:  Correct functional group i.e. - al/Korrekte funksionele groep d.i. -al.   Whole name correct/Hele naam korrek.  (2) 2.3 2.3.1 Oxidation/combustion/oksidasie/verbranding  (1) 2.3.2 C8H18  (2 or/of 0) (2) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om assseblief ### Page 26 Downloaded from hlayiso.com Physical Sciences/P2/Fisiese Wetenskappe/V2 4 DBE/September 2021(2) SC/NSC/SS/NSS – Marking Guidelines/Nasienriglyne 2.3.3 OPTION 1/OPSIE 1 Marking criteria/Nasienkriteria V(CO2) = 8 x VB  Use volume ratio/Gebruik volume verhouding: = 8(50) V(CO2) : V(B) = 2 : 1 and/en = 400 cm3 V(H2O) : V(B) = 9 : 1  18  Add/Tel bymekaar: V(CO2) and/en V(H2O)  V(H2O) = VB   Final answer/Finale antwoord: 850 cm3  2 = 9(50) OPTION 2/OPSIE 2 = 450 cm3  2 mol CXHY .......... 16 + 18 = 34 mol gas Total volume gas formed/ Totale volume gas gevorm 50 mol CXHY .......... 25 x 34  mol gas  = 400 + 450 = 850 cm3  Total moles gas formed/Totale volume gas gevorm = 850 cm3  (3) [16] QUESTION 3/VRAAG 3 3.1 No/Nee  (1) - 3.2 There is more than one independent variable.  Daar is meer as een onafhanklike veranderlike. OR/OF Positions of functional groups and branching/chain length differ. Posises van funksionele groepe en vertakking/kettinglengte verskil. OR/OF Compounds A and B/C are positional isomers and compounds B and C are chain isomers. Verbindings A en B/C is posisie-isomere en verbindings B en C is kettingisomere. (1) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om assseblief ### Page 27 Downloaded from hlayiso.com Physical Sciences/P2/Fisiese Wetenskappe/V2 5 DBE/September 2021(2) SC/NSC/SS/NSS – Marking Guidelines/Nasienriglyne 3.3  B/butan-2-ol is less branched / less compact / less spherical/ has a longer chain length / has a larger surface area (over which intermolecular forces act).  B/butan-2-ol has stronger / more intermolecular forces / Van der Waals forces / London forces / dispersion forces.   More energy needed to overcome or break intermolecular forces / Van der Waals forces in B/butan-2-ol.   B/butan-2-ol is minder vertak / minder kompak / minder sferies / het 'n langer kettinglengte / het 'n groter oppervlak (waaroor intermolekulêre kragte werk).  B/butan-2-ol het sterker / meer intermolekulêre kragte / Van der Waalskragte / London-kragte / dispersiekragte.  Meer energie benodig om intermolekulêre kragte / Van der Waalskragte/ dispersiekragte / London-kragte te oorkom in B/butan-2-ol. OR/OF  C/2-methylpropan-2-ol is more branched / more compact / more spherical / has a smaller surface area (over which intermolecular forces act).  C/2-methylpropan-2-ol has weaker / less intermolecular forces / Van der Waals forces / London forces / dispersion forces.   Less energy needed to overcome or break intermolecular forces / Van der Waals forces in C/2-methylpropan-2-ol.   C/2-metielpropan-2-ol is meer vertak / meer kompak / meer sferies / het 'n kleiner oppervlak (waaroor intermolekulêre kragte werk).  C/2-metielpropan-2-ol het swakker/minder intermolekulêre kragte / Van der Waalskragte / Londonkragte / dispersiekragte.  Minder energie benodig om intermolekulêre kragte / Van der Waalskragte/ dispersiekragte / Londonkragte te oorkom in C/ 2-metielpropan-2-ol. (3) 3.4 Marking criteria/Nasienkriteria If any one of the underlined key phrases in the correct context is omitted, deduct 1 mark./Indien enige van die onderstreepte frases in die korrekte konteks uitgelaat is, trek 1 punt af. Compounds with the same molecular formula, but different positions of the side chain/substituents/functional groups on parent chain.  Verbindings met dieselfde molekulêre formule, maar verskillende posisies van die syketting/substituente/funksionele groepe op die stamketting. (2) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om assseblief ### Page 28 Downloaded from hlayiso.com Physical Sciences/P2/Fisiese Wetenskappe/V2 6 DBE/September 2021(2) SC/NSC/SS/NSS – Marking Guidelines/Nasienriglyne 3.5 3.5.1 A&B (1) 3.5.2 C The C-atom bonded to the functional group/OH-group/hydroxyl (group) is bonded to three other C-atoms.  Die C-atoom aan die funksionele groep/OH-groep/hidroksiel(groep) gebind is, is aan drie ander C-atome gebind. OR/OF The functional group/OH-group/hydroxyl (group) is bonded to a tertiary C- atom. Die funksionele groep/OH-groep/hidroksiel(groep) is aan 'n tersiêre C-atoom gebind. (2) 3.6 3.6.1 101,3 (kPa) / 1,013 x 105 Pa / 1 atm / 760 mmHg  (1) 3.6.2 Marking criteria/Nasienkriteria:  Curve C is above A. Kurwe C is bokant A.  Vapour pressure (kPa) C  Value 82 °C on curve C where A vapour pressure is X/ 101,3 kPa. Waarde 82 °C op kurwe C waar dampdruk gelyk is aan X/ 101,3 kPa.  IF/INDIEN: X  Curves start at same point/Indien kurwes by dieselfde punt begin: 82 117 Max./Maks. 1 2 Temperature (°C)  Straight line graph/Reguitlyn grafiek. Max./Maks. 1 2 (2) [13] Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om assseblief ### Page 29 Downloaded from hlayiso.com Physical Sciences/P2/Fisiese Wetenskappe/V2 7 DBE/September 2021(2) SC/NSC/SS/NSS – Marking Guidelines/Nasienriglyne QUESTION 4/VRAAG 4 4.1 4.1.1 Substitution/halogenation/bromination  Substitusie/halogenering/brominering (1) 4.1.2 Substitution/hydrolysis/Substitusie/hidrolise  (1) 4.1.3 1-bromopropane/1-bromopropaan  IF/INDIEN: Bromopropane/bromopropaan OR/OF 2-bromopropane/2-bromopropaan Max./Maks. 1 2 (2) 4.1.4 H2SO4/(concentrated) sulphuric acid/(gekonsentreerde) swaelsuur  (1) 4.1.5 Ethanoic acid/Etanoësuur  (2) 4.1.6 H H H O H Marking criteria/Nasienkriteria:  Functional group correct.  H C C C O C C H Funksionele groep korrek.  Whole structure correct.  H H H H Hele struktuur korrek. Notes/Aantekeninge:  One or more H atoms omitted: / Een of meer H-atome uitgelaat: 1 2  Condensed or semi-structural formula: / Gekondenseerde of semi-struktuur- formule: 1 2 (2) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om assseblief ### Page 30 Downloaded from hlayiso.com Physical Sciences/P2/Fisiese Wetenskappe/V2 DBE/September 2021(2) SC/NSC/SS/NSS – Marking Guidelines/Nasienriglyne 4.2 H H H H  H H H H H2SO4  H C C C C H + H2O H C C C C H H H H O H H  H H H H H H H H H   H2SO4  H C C C C H C H + H2O heat/hitte H C C C H O H H H H H Notes/Aantekeninge:  Condensed or semistructural formula: Max. 5 6 Gekondenseerde of semistruktuurformule: Maks. 5 6  Molecular formula/Molekulêre formule: Max./Maks. 3 6  Marking rule 6.3.10/Nasienreël 6.3.10.  Any additional reactants or products: Max. 5 6 Enige addisionele reaktanse of produkte: Maks. 5 6  If arrow in equation omitted: Max. 5 6 Indien pyltjie in vergelyking uitgelaat is: Maks. 5 6 (6) [15] Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om assseblief ### Page 31 Downloaded from hlayiso.com Physical Sciences/P2/Fisiese Wetenskappe/V2 9 DBE/September 2021(2) SC/NSC/SS/NSS – Marking Guidelines/Nasienriglyne QUESTION 5/VRAAG 5 5.1 5.1.1 Kinetic energy/kinetiese energie  (1) 5.1.2 Number of particles/molecules  Aantal deeltjies/molekule (1) 5.2 5.2.1 Activation energy/Aktiveringsenergie  (1) 5.2.2 Increase/Toeneem  (1) 5.3  A catalyst provides an alternative pathway of lower activation energy.   More molecules have sufficient kinetic energy.   More effective collisions per unit time./Frequency of efffective collisions increases.   Increase raction rate.   'n Katalisator verskaf 'n alternatiewe roete van laer aktiveringsenergie.  Meer molekule het voldoende kinetiese energie.  Meer effektiewe botsings per eenheidtyd./Frekwensie van effektiewe botsings neem toe.  Verhoog reaksietempo.  (4) 5.4 5.4.1 Temperature / Surface area / Amount or mass of CaCO3  Temperatuur / Reaksie-oppervlak / Hoeveelheid of massa CaCO3 (1) 5.4.2 Criteria for conclusion/Kriteria vir gevolgtrekking: Dependent (reaction rate) and independent (concentration) variables correctly identified./Afhanklike(reaksietempo) en onafhanklike (konsentrasie)  - veranderlikes korrek geïdentifiseer. Relationship between the independent and dependent variables correctly stated. Verwantskap tussen die afhanklike en onafhanklike veranderlikes korrek  genoem. Example/Voorbeeld: Reaction rate is directly proportional to concentration. Reaksietempo is direk eweredig aan konsentrasie. IF/INDIEN Reaction rate increases with increase in concentration. Reaksietempo neem toe met toename in konsentrasie. OR/OF Reaksietempo is eweredig aan konsentrasie. Reaction rate is proportional to concentration. Max./Maks. 1 2 (2) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om assseblief ### Page 32 Downloaded from hlayiso.com Physical Sciences/P2/Fisiese Wetenskappe/V2 DBE/September 2021(2) SC/NSC/SS/NSS – Marking Guidelines/Nasienriglyne 5.5 Marking criteria/Nasienkriteria: V  Substitute 50 cm3∙min-1 and 26 minutes in rate =  t  Substitute/ Vervang 1 300 cm3 /1,3 dm3 OR/OF 24 000 cm3∙mol-1/ 24 dm3∙mol-1 V in n =  Vm  Use ratio/Gebruik verhouding n(CO2) = n(CaCO3) = 1:1  m  Substitute/Vervang 100 g∙mol-1 in n =  M m(CaCO 3 )  Calculate % purity/Bereken % suiwerheid =  x 100 m(Sample/ monster )  Final answer/Finale antwoord: 90,33%  Range/Gebied: 83,33% to 90,33% OPTION 1 OPTION 2: V 50 Rate/tempo = Rate/tempo = t 24 000  V = 0,00208 mol∙min-1  50 = 26  ΔV = 1 300 cm3 n(CO2) = 0,00208 x 26 = 0,0542 mol 1300 1,3 n(CO2) =  OR n(CaCO3) = n(CO2) = 0,0542 mol  24 000 24 = 0,0542 mol m(CaCO3) = nM  n(CaCO3) = n(CO2) = 0,0542(100) = 0,0542 mol  = 5,42 g m(CaCO3) = nM 5,42  % purity/suiwerheid =  x 100 = 0,0542 x 100 6 = 5,42 g = 90,33%  5,42 % purity/suiwerheid =  x 100 6 = 90,33%  (6) [17] Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om assseblief ### Page 33 Downloaded from hlayiso.com Physical Sciences/P2/Fisiese Wetenskappe/V2 11 DBE/September 2021(2) SC/NSC/SS/NSS – 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.  (2 or 0) Die stadium in 'n chemiese reaksie waar die tempo van die voorwaartse reaksie gelyk is aan die tempo van die terugwaartse reaksie. (2 of 0) OR/OF The stage in a chemical reaction when the concentrations of reactants and products remain constant. (2 or 0) Die stadium in 'n chemiese reaksie waar die konsentrasies van die reaktanse en produkte konstant bly. (2 of 0) (2) 6.2 CALCULATIONS USING NUMBER OF MOLES BEREKENINGE WAT AANTAL MOL GEBRUIK Marking criteria/Nasienkriteria m  Substitute/Vervang 18 g∙mol-1 in n =  M  Δn(CO2) = Δn(C) = 0,225 mol.   Use mole ratio/Gebruik n(C) : n(H2O) : n(CO2) : n(H2) = ! : 2 : 1 : 2   Equilibrium/Ewewig n(H2O) = initial/aanvaklike n(H2O) - ∆n(H2O) Equilibrium/Ewewig n(H2) = initial/aanvanklike n(H2) + ∆n(H2)  Equilibrium/Ewewig n(CO2) = initial/aanvanklike n(CO2) + ∆n(CO2)  Divide equilibrium moles of H2O, H2 AND/EN CO2 by/deur 2 dm3.  Correct Kc expression (formulae in square brackets).  Korrekte Kc uitdrukking (formules in vierkantige hakies).  Substitution of concentrations into correct Kc expression.  Vervanging van konsentrasies in korrekte Kc-uitdrukking.  Final answer/Finale antwoord: 0,00948  Range/Gebied: 0,00948 to/tot 0,01 (9,48 x 10-3 to/tot 1 x 10-2) OPTION 1/OPSIE 1 m 36 n(H2O)initial/aanvanklik = = = 2 mol M 18 H2O H2 CO2 Initial amount (moles) 2 Aanvangs hoeveelheid (mol) Change in amount (moles) ratio  0,45 0,45 0,225  verhouding Verandering in hoeveelheid (mol) Equilibrium amount (moles) 1,55 0,45 0,225  hoeveelheid (mol) Divide by/ Equilibrium concentration (mol∙dm-3) Deel deur 0,775 0,225 0,1125 Ewewigskonsentrasie (mol∙dm-3) 2 dm3  No Kc expression, correct substitution/Geen Kc- 2 [H2 ] [CO2 ] uitdrukking, korrekte substitusie: Max./Maks. 7 8 Kc =  [H2 O] 2 Wrong Kc expression/Verkeerde Kc-uitdrukking: [0,225] 2 [0,1125] =  Max./Maks. 5 [0,775] 2 8 = 0,00948  Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om assseblief ### Page 34 Downloaded from hlayiso.com Physical Sciences/P2/Fisiese Wetenskappe/V2 DBE/September 2021(2) SC/NSC/SS/NSS – Marking Guidelines/Nasienriglyne CALCULATIONS USING CONCENTRATION BEREKENINGE WAT KONSENTRASIE GEBRUIK m  Substitute/Vervang 18 g∙mol-1 in n =  M  Divide initial/Deel aanvanklike n(H2O) AND Δn(CO2) by/deur 2 dm3.  Δn(CO2) = Δn(C) = 0,225 mol OR/OF Δc(CO2) = 0,1125 mol·dm-3.   Use mole ratio/Gebruik molverhouding n(H2O) : n(CO2) : n(H2) = 2 : 1 : 2   Equilibrium/Ewewig c(H2O) = initial/aanvanklike c(H2O) - ∆c(H2O) Equilibrium/Ewewig c(H2) = initial/aanvanklike c(H2) + ∆c(H2)  Equilibrium/Ewewig c(CO2) = initial/aanvanklike c(CO2) + ∆c(CO2)  Correct Kc expression (formulae in square brackets).  Korrekte Kc uitdrukking (formules in vierkantige hakies).  Substitution of concentrations into correct Kc expression.  Vervanging van konsentrasies in korrekte Kc-uitdrukking.  Final answer/Finale antwoord: 0,00948  Range/Gebied: 0,00948 – 0,01) OPTION 2/OPSIE 2 m 36 n(H2O)initial/aanvanklik = = = 2 mol M 18  H2O H2 CO2 Divide by/ -3 Initial concentration (mol∙dm ) Deel deur 1 Aanvangskonsentrasie (mol∙dm-3) 2 dm3  Change (mol∙dm-3)  ratio  0,225 0,225 0,1125  verhouding Verandering (mol∙dm-3) Equilibrium concentration (mol∙dm-3) 0,775 0,225 0,1125 Ewewigskonsentrasie (mol∙dm-3) No Kc expression, correct substitution/Geen Kc- 2 [H2 ] [CO2 ] uitdrukking, korrekte substitusie: Max./Maks. 7 8 Kc =  [H2 O] 2 Wrong Kc expression/Verkeerde Kc-uitdrukking: [0,225] 2 [0,1125] =  Max./Maks. 5 [0,775] 2 8 = 0,00948  (8) 6.3 6.3.1 Steam is used up./Amount of steam decreases./Concentration of steam decreases./Reactants are used up.  Water word opgebruik./Hoeveelheid stoom neem af./Konsentrasie van stoom neem af./Reaktanse word opgebruik. (1) 6.3.2 Catalyst was added./Katalisator is bygevoeg.  (1) 6.3.3 Endothermic/Endotermies  (1) - 6.3.4  The forward reaction is favoured./Die voorwaartse reaksie word bevoordeel.   Increase in temperature favours the endothermic reaction.  Toename in temperatuur bevoordeel die endotermiese reaksie. (2) [15] Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om assseblief ### Page 35 Downloaded from hlayiso.com Physical Sciences/P2/Fisiese Wetenskappe/V2 13 DBE/September 2021(2) SC/NSC/SS/NSS – Marking Guidelines/Nasienriglyne QUESTION 7/VRAAG 7 7.1 A base forms hydroxide ions (OH-) in water/aqueous solution/OH-(aq).  'n Basis vorm hidroksiedione (OH-) in water/waterige oplossing/OH-(aq). IF/INDIEN: A base ionises to form hydroxide ions (OH-).  'n Basis ioniseer om hidroksiedione (OH-) te vorm. Max./Maks. 1 2 (2) 7.2 n(KOH) = cV = 0,1 x 0,4  = 0,04 mol - n(OH ) = n(KOH) = 0,04 mol (2) 7.3 7.3.1 POSITIVE MARKING FROM Q7.2/POSITIEWE NASIEN VANAF V7.2 Marking criteria/Nasienkriteria  Use formula/Gebruik formule: pH = -log[H3O+]  Substitute/Vervang pH = 13/pOH = 1  Substitute/Vervang 1 x 10-13 in Kw/Calculate/Bereken pOH  Substitute/Vervang of 0,1 x 0,9  Calculate/Bereken n(OH-) = n(in C) – n(in B)   Use mol ratio/Gebruik molverhouding: n(Ba(OH)2) : n(OH-) = 1 : 2.   Substitute/Vervang 0,5 dm3.   Final answer/Finale antwoord: 0,05 mol·dm-3  Range/Gebied: 0,05 to 0,06 mol·dm-3 OPTION 1/OPSIE 1 OPTION 2/OPSIE 2 pH = -log[H3O+] OR/OF [H3O+] = 10-pH  pOH = 14 - 13 = 1  13 = -log[H3O+] OR/OF [H3O] = 10-13 pOH = -log[OH-]  [H3O+] = 1 x 10-13 mol·dm-3 1  = -log[OH-] [OH-] = 0,1 mol·dm-3 [H3O+][OH-] = 1 x 10-14 (1 x 10-13) [OH-] = 1 x 10-14  n(OH-) = cV [OH-] = 0,1 mol·dm-3 = 0,1 x 0,9  = 0,09 mol n(OH-) = cV = 0,1 x 0,9  = 0,09 mol n(OH-) from/van Ba(OH)2 in beaker/beker C = 0,09 - 0,04 = 0,05 mol n[Ba(OH)2] = ½ n(OH-) = ½ (0,05)  = 0,025 mol n c[Ba(OH)2] = V 0,025 = 0,5   x = 0,05 mol·dm-3  (8) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om assseblief ### Page 36 Downloaded from hlayiso.com Physical Sciences/P2/Fisiese Wetenskappe/V2 14 DBE/September 2021(2) SC/NSC/SS/NSS – Marking Guidelines/Nasienriglyne 7.3.2 Weak (acid)/Swak (suur)  - Ionises/dissociates incompletely/partially.  Ioniseer/dissosieer onvolledig/gedeeltelik. (2) 7.3.3 POSITIVE MARKING FROM Q7.3.1/POSITIEWE NASIEN VANAF V7.3.1 Marking criteria/Nasienkriteria n c a  Va na  Formula/Formule: c  /  . V c b  Vb nb  Substitution of/Vervanging van 0,1 x 15 / 0,1 x 0,015  OR/OF Use/Gebruik Va = 30 cm3  Use mol ratio/Gebruik molverhouding 1 : 1   Final answer/Finale antwoord: 0,05 mol∙dm-3. OPTION 1/OPSIE 1 OPTION 2/OPSIE 2 n(OH−) = cV  c a  Va n a = 0,1 x 0,015    c b  Vb nb = 0,0015 mol c a  30 1   n(CH3COOH) = n(OH−) 0,1  15 1 = 0,0015 mol  ca = 0,05 mol∙dm-3  n c V 0,0015  0,03  0,05 mol  dm 3  (4) [18] Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om assseblief Text truncated here. 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