Physical Sciences Grade 12 P2 Eastern Cape Prelim 2024 QP

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE GRADE 12 SEPTEMBER 2024 PHYSICAL SCIENCES P2 (CHEMISTRY) MARKS: 150 TIME: 3 hours This question paper consists of 19 pages, including 4 data sheets. Hosted by www.ecexams.co.za.

Downloaded from hlayiso.com 2 PHYSICAL SCIENCES P2 (EC/SEPTEMBER 2024) INSTRUCTIONS AND INFORMATION 1. Write your full NAME and SURNAME in the appropriate spaces on the ANSWER BOOK. 2. This question paper consists of NINE questions. Answer ALL the questions in the ANSWER BOOK. 3. Start EACH question on a NEW page in the ANSWER BOOK. 4. Number the answers correctly according to the numbering system used in this question paper. 5. Leave ONE line between two subquestions, for example between QUESTION 2.1 and QUESTION 2.2. 6. You may use a non-programmable calculator. 7. You may use appropriate mathematical instruments. 8. Show ALL formulae and substitutions in ALL calculations. 9. Round off your FINAL numerical answers to a minimum of TWO decimal places. 10. Give brief motivations, discussions, et cetera where required. 11. You are advised to use the attached DATA SHEETS. 12. Write neatly and legibly. Copyright reserved Please turn over Hosted by www.ecexams.co.za.

Downloaded from hlayiso.com (EC/SEPTEMBER 2024) PHYSICAL SCIENCES P2 3 QUESTION 1: MULTIPLE-CHOICE QUESTIONS Various 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, for example 1.11 E. 1.1 Which ONE of the following homologous series contains a hydroxyl group that is bonded to a saturated carbon atom? A Ketones B Aldehydes C Alcohols D Esters (2) 1.2 Consider the compound shown below: CH3 CH2CH3 H C C C H O H H The CORRECT IUPAC name of the above compound is: A 3-ethyl-2-methylpropanal B 2-methyl-3-ethylpropanal C 2-methylpentanal D 4-methylpentanal (2) 1.3 Consider the reaction: C3H6 + Cℓ2 → C3H6Cℓ2 The name of the reaction is … A hydration B halogenation C hydrogenation D hydrolysis (2) Copyright reserved Please turn over Hosted by www.ecexams.co.za.

Downloaded from hlayiso.com 4 PHYSICAL SCIENCES P2 (EC/SEPTEMBER 2024) 1.4 Consider the vapour pressure against temperature curves for THREE CHAIN ISOMERS under standard atmospheric pressure. VAPOUR PRESSURE VERSUS TEMPERATURE Vapour pressure (kPa) A B C 101 T1 T2 T3 Temperature (K) Consider the statements regarding the curves for the THREE CHAIN ISOMERS. I Compound A has the shortest chain length. II The boiling point of compound B is T2. III Compound C is at a gaseous phase at T2. Which of the above statement(s) is/are true? A I and II only B III only C II and III only D I and III only (2) 1.5 Consider the synthesis reaction of ammonia, NH3: N2 (g) + 3 H2 (g) ⇌ 2 NH3 (g) The rate at which N2 (g) is consumed during the reaction is 𝒙 mol·dm-3·s-1. Which ONE of the following is the rate at which ammonia, NH3 (g) is produced in mol·dm-3·s-1 with respect to N2 (g)? A 𝒙 B 2𝒙 𝒙 C 2 D 3𝒙 (2) Copyright reserved Please turn over Hosted by www.ecexams.co.za.

Downloaded from hlayiso.com (EC/SEPTEMBER 2024) PHYSICAL SCIENCES P2 5 1.6 Consider the following reaction at equilibrium: CoCℓ42– (aq) + 6 H2O (ℓ) ⇌ Co(H2O)62+ (aq) + 4 Cℓ – (aq) Blue Pink The solution is currently pink. Concentrated hydrochloric acid (HCℓ) is added to the equilibrium mixture. Which ONE of the following combinations CORRECTLY describes the effect that the addition of concentrated hydrochloric acid (HCℓ) will have on the equilibrium constant, Kc and the colour change of the solution? Kc COLOUR CHANGE A No Effect Solutions turns pinker B No Effect Solution turns blue C Increases Solution turns blue D Decreases Solution turns pinker (2) 1.7 Which ONE of the following substances can be classified as a Lowry-Brønsted acid? A Na2CO3 B KOH C NH4+ D NaCℓ (2) 1.8 Consider the salt, CH3COONa. Which ONE of the following combinations CORRECTLY identifies the hydrolysis reaction and the pH of the salt? HYDROLYSIS pH A CH3COO– + H2O ⇌ CH3COOH + OH – Greater than 7 B CH3COO– + H2O ⇌ CH3COOH + OH – Less than 7 C Na+ + H2O ⇌ NaOH + H2O Greater than 7 D CH3COO– + Na+ ⇌ CH3COONa Equal to 7 (2) Copyright reserved Please turn over Hosted by www.ecexams.co.za.

Downloaded from hlayiso.com 6 PHYSICAL SCIENCES P2 (EC/SEPTEMBER 2024) 1.9 Consider the cell notation of a galvanic cell below: Aℓ│Aℓ3+││MnO4– , Mn2+│Pt Which ONE of the following reactions occurs at the cathode? A Mn2+ + 4 H2O → MnO4– + 8 H+ + 5 e– B MnO4– + 8 H+ + 5 e– → Mn2+ + 4 H2O C Aℓ → Aℓ3++ 3 e– D Aℓ3++ 3 e– → Aℓ (2) 1.10 A spoon is plated with silver (Ag) during the process of electrolysis. Ag spoon Ag+ (aq) Which ONE of the following graphs BEST represents the concentration of the silver ions (Ag+) in the electrolyte over time? A B Concentration Concentration (mol·dm-3) (mol·dm-3) time time C D Concentration Concentration (mol·dm-3) (mol·dm-3) time time (2) [20] Copyright reserved Please turn over Hosted by www.ecexams.co.za.

Downloaded from hlayiso.com (EC/SEPTEMBER 2024) PHYSICAL SCIENCES P2 7 QUESTION 2 (Start on a new page.) Consider the organic compounds A–E below. A B 3-methylbutanone C3H7Cℓ C D H H H CH3 │ │ │ │ H —C —C —H H — C — C ≡ C — C — H │ │ │ │ H H H CH2CH3 E H H O │ │ H — C — C —C — O — H │ │ H H 2.1 Define functional group. (2) 2.2 Write down the LETTER of a compound that: 2.2.1 Contains a carboxyl group (1) 2.2.2 Has the general formula CnH2nO (1) 2.2.3 Has an empirical formula of CH2 (1) 2.3 How will the molecular mass of compound E compare to ethyl methanoate? Choose from GREATER THAN, SMALLER THAN or EQUAL TO. Give a reason for the answer. (3) 2.4 Write down the: 2.4.1 STRUCTURAL FORMULA of compound A (2) 2.4.2 IUPAC name of compound E (2) 2.4.3 IUPAC name of compound D (3) 2.5 Compound B is a secondary haloalkane. Draw the STRUCTURAL FORMULA of compound B. (2) 2.6 Using the MOLECULAR FORMULAE, write down the balanced equation for the complete combustion of compound D. (3) [20] Copyright reserved Please turn over Hosted by www.ecexams.co.za.

Downloaded from hlayiso.com 8 PHYSICAL SCIENCES P2 (EC/SEPTEMBER 2024) QUESTION 3 (Start on a new page.) 3.1 The relationship between boiling point and the number of carbons in STRAIGHT CHAIN PRIMARY ALCOHOLS is investigated. The following curve is obtained: GRAPH OF BOILING POINT VERSUS NUMBER OF C ATOMS 500 Boiling point (K) 400 300 200 100 1 2 3 4 5 6 7 8 Number of carbons 3.1.1 Define boiling point. (2) 3.1.2 What is the structural similarity between the alcohols that make this a fair investigation? (1) 3.1.3 Which van der Waals force is responsible for the trend observed in this curve? (1) 3.1.4 Write down the IUPAC name of the alcohol with a boiling point of approximately 410 K. (2) 3.2 Another investigation is carried out to determine the effect of structural differences on the boiling point. The table below shows the different compounds and their respective molar mass that was used in this investigation. COMPOUND MOLAR MASS (g·mol-1) A Butanone 72 B Butan-1-ol 74 C Propanoic acid 74 3.2.1 Which compound A, B or C will have the highest boiling point? (1) 3.2.2 Fully explain the answer to QUESTION 3.2.1. (5) [12] Copyright reserved Please turn over Hosted by www.ecexams.co.za.

Downloaded from hlayiso.com (EC/SEPTEMBER 2024) PHYSICAL SCIENCES P2 9 QUESTION 4 (Start on a new page.) 4.1 Consider the three organic reactions, I, II and III below: I Pent-1-ene + HCℓ → Organic compound P (Major product) II Organic compound P + NaOH → secondary alcohol Q + NaCℓ III Organic compound P + NaOH → Organic compound R + NaCℓ + H2O (Major product) 4.1.1 Is pent-1-ene SATURATED or UNSATURATED? Give a reason for the answer. (2) Write down the type of reaction represented by: 4.1.2 Reaction II (1) 4.1.3 Reaction III (1) Write down the: 4.1.4 STRUCTURAL FORMULA of compound P. (2) 4.1.5 IUPAC name of compound Q. (2) 4.1.6 Reactions II and III require the use of a strong base. Write down the conditions that will prefer reaction II over reaction III. (2) 4.1.7 Pent-1-ene and organic compound R are isomers. What type of isomer is pent-1-ene and organic compound R? Choose from FUNCTIONAL, POSITIONAL or CHAIN. (2) 4.2 The flow diagram below shows the conversion of butan-1-ol to butane gas. Step 1 Step 2 Butan-1-ol Organic compound X Butane The following chemicals are needed: Concentrated H2SO4 Pt H2 Using CONDENSED STRUCTURAL FORMULAE, write down the balanced equation and indicate the chemicals used in each step in the preparation of butane gas from butan-1-ol. (6) [18] Copyright reserved Please turn over Hosted by www.ecexams.co.za.

Downloaded from hlayiso.com 10 PHYSICAL SCIENCES P2 (EC/SEPTEMBER 2024) QUESTION 5 (Start on a new page.) The reaction between EXCESS hydrochloric acid (HCℓ) with zinc (Zn) is used to investigate factors that influences the reaction rate. The balanced equation for this reaction is: Zn (s) + 2 HCℓ (aq) → ZnCℓ2 (aq) + H2 (g) ΔH < 0 Three experiments are carried out and one factor is changed in each experiment. The same volume of hydrochloric acid and the same mass of zinc granules are used in each experiment. The hydrochloric acid completely covers the zinc in each experiment. The table below shows the reaction conditions. EXPERIMENT CONCENTRATION OF HCℓ Cu (s) PRESENT (mol·dm-3) 1 0,5 No 2 0,8 No 3 0,5 Yes 5.1 Define reaction rate. (2) 5.2 Write down an investigative question when comparing experiments 1 and 2. (2) 5.3 The curve, not drawn to scale, is obtained for the volume of hydrogen gas, H2 (g) produced over time for experiment 1. VOLUME OF HYDROGEN GAS VERSUS TIME t1 t2 t3 time 5.3.1 How does the rate at which hydrogen gas is produced between t1–t2 compare to that at t2–t3? Write down only HIGHER THAN, LOWER THAN or EQUAL TO. (1) Copyright reserved Please turn over Hosted by www.ecexams.co.za.

Downloaded from hlayiso.com (EC/SEPTEMBER 2024) PHYSICAL SCIENCES P2 11 5.3.2 Redraw the graph in the ANSWER BOOK. Clearly label the curve as A. On the same set of axes, sketch the curve that will be obtained for experiment 3. Label this curve as B. (2) 5.4 The reaction in experiment 1 takes 58 s to reach completion and the average reaction rate at which hydrogen gas, H2 is produced is 8,39 cm3·s-1. Calculate the initial mass of zinc used in each experiment. The molar volume for hydrogen gas (H2) at 25 °C is 24 000 cm3·mol-1. Experiment 4 is now conducted by increasing the temperature of the reaction mixture in experiment 1. (5) 5.5 How will this change affect the reaction rate? Choose from INCREASES, DECREASES or REMAINS THE SAME. (1) 5.6 Explain the answer to QUESTION 5.5 by referring to the collision theory. (3) [16] Copyright reserved Please turn over Hosted by www.ecexams.co.za.

Downloaded from hlayiso.com 12 PHYSICAL SCIENCES P2 (EC/SEPTEMBER 2024) QUESTION 6 (Start on a new page.) 6.1 Consider the following hypothetical reaction at equilibrium: A (g) ⇌ 2 B (g) The data in the table below shows the equilibrium concentrations of A (g) and B (g) at different temperatures: Temperature (°C) A (mol·dm-3) B (mol·dm-3) 200 0,0125 0,843 300 0,171 0,764 6.1.1 State Le Chaterlier’s principle. (2) 6.1.2 Is the FORWARD or REVERSE reaction favoured at 200 °C? Give a reason for the answer. (2) How will the equilibrium concentration of A at 200 °C be affected by the following: Choose from INCREASES, DECREASES or NO EFFECT 6.1.3 The pressure is increased. (1) 6.1.4 Addition of a suitable catalyst. (1) 6.1.5 Is the forward reaction EXOTHERMIC or ENDOTHERMIC? (1) 6.1.6 Use Le Chatelier’s principle and refer to the data in the table to explain the answer to QUESTION 6.1.5. (3) 6.2 Initially 1,05 moles of Bromine (Br2) are sealed in an empty container. The following reaction occurs at 1 600 °C. Br2 (g) ⇌ 2 Br (g) At equilibrium the concentration of Bromine (Br2) is 2,074 mol·dm-3. The equilibrium constant, Kc is 6,34 x 10-4 at 1 600 °C. Calculate the volume of the container. (7) [17] Copyright reserved Please turn over Hosted by www.ecexams.co.za.

Downloaded from hlayiso.com (EC/SEPTEMBER 2024) PHYSICAL SCIENCES P2 13 QUESTION 7 (Start on a new page.) 7.1 Sulphuric acid, H2SO4 is a strong acid that ionises in two steps as represented by the equations below: Step 1: H2SO4 (aq) + H2O (ℓ) ⇌ HSO4 – (aq) + H3O+ (aq) Step 2: HSO4 – (aq) + H2O (ℓ) ⇌ SO42 – (aq) + H3O+ (aq) 7.1.1 Explain what is meant by strong acid. (2) 7.1.2 Give a reason why sulphuric acid is referred to as a diprotic acid. (1) 7.1.3 Write down the conjugate base of H3O+. (1) 7.1.4 Write down the FORMULA of the substance that acts as an ampholyte during the ionisation of sulphuric acid. (2) Sulphuric acid has a concentration of 0,1 mol·dm-3. 7.1.5 Calculate the pH value after complete ionisation. (4) 7.2 1,2 g of anhydrous oxalic acid (H2C2O4) is dissolved in water to make a 50 cm3 solution. 7.2.1 Calculate the concentration of the oxalic acid, H2C2O4. (3) Learners dissolve x g of sodium hydroxide, NaOH to make a 2 dm3 solution of sodium hydroxide, NaOH (aq). They transfer 25 cm3 of the sodium hydroxide, NaOH solution to a volumetric flask and added distilled water to make a diluted 100 cm3 solution. Distilled water 2 dm3 100 cm3 x g NaOH 2 dm3 NaOH 25 cm3 NaOH They titrate 43,8 cm3 of the diluted sodium hydroxide, NaOH solution against 25 cm3 oxalic acid, H2C2O4 prepared in QUESTION 7.2.1 to reach the endpoint. The balanced equation is: H2C2O4 (aq) + 2 NaOH (aq) → Na2C2O4 (aq) + 2 H2O (ℓ) 7.2.2 Calculate the mass, x g of sodium hydroxide that was used to make the 2 dm3 solution. (7) [20] Copyright reserved Please turn over Hosted by www.ecexams.co.za.

Downloaded from hlayiso.com 14 PHYSICAL SCIENCES P2 (EC/SEPTEMBER 2024) QUESTION 8 (Start on a new page.) A standard electrochemical cell is set up as shown below. V Pb Pt Y Pb2+ (aq) Fe2+, Fe3+ (aq) 8.1 State the energy conversion that takes place in this cell. (2) 8.2 Component Y ensures that the cell is complete. State ONE other function of component Y. (1) 8.3 Write down the reduction half reaction. (2) 8.4 Calculate the initial emf of this cell. (4) 8.5 How will the reading on the voltmeter be affected, if the: Choose from INCREASES, DECREASES or REMAINS THE SAME 8.5.1 Initial concentration of Pb2+ is increased. (1) 8.5.2 Surface area of the Pt electrode is increased. (1) 8.5.3 The Pb│Pb2+ half-cell is replaced with Zn│Zn2+. (1) 8.6 Explain the answer to QUESTION 8.5.3 by referring to the relative strength of the reducing agents. (2) [14] Copyright reserved Please turn over Hosted by www.ecexams.co.za.

Downloaded from hlayiso.com (EC/SEPTEMBER 2024) PHYSICAL SCIENCES P2 15 QUESTION 9 (Start on a new page.) A few drops of phenolphthalein are added to concentrated sodium chloride (NaCℓ) solution. The solution remains colourless. Carbon electrodes P and Q that are connected to a battery is dipped into the solution as shown below. P Q NaCℓ (aq) 9.1 Define electrolysis. (2) 9.2 Write down the name of the component that shows that the above cell is an electrolytic cell. (1) 9.3 Write down the NAME or FORMULA of the gas produced at electrode Q. (1) 9.4 Write down the half reaction that occurs on electrode P. (2) 9.5 Phenolphthalein is COLOURLESS in an acidic solution and PINK in an alkaline solution. Write down the colour of the solution around electrode Q and formula of the substance responsible for the colour. (2) 9.6 An electrolytic cell is set-up for the purification of copper (Cu) ore that contains zinc (Zn) and platinum (Pt) impurities. After the purification of the impure copper was completed, 1,38 x 10-2 mol of electrons were transferred. The initial mass of the cathode is 2 g. 9.6.1 Which metal, besides copper, will be oxidised? Choose from zinc or platinum. (1) 9.6.2 Calculate the mass of the cathode after the purification. (4) [13] TOTAL: 150 Copyright reserved Please turn over Hosted by www.ecexams.co.za.

Downloaded from hlayiso.com 16 PHYSICAL SCIENCES P2 (EC/SEPTEMBER 2024) NATIONAL SENIOR CERTIFICATE NASIONALE SENIOR SERTIFIKAAT 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 NAAM/NAME SIMBOOL/SYMBOL WAARDE/VALUE Standard pressure p 1,013 × 105 Pa Standaarddruk Molar gas volume at STP Vm 22,4 dm3∙mol-1 Molêre gasvolume teen STD Standard temperature Tθ 273 K Standaardtemperatuur Charge on electron e -1,6 × 10-19 C Lading op elektron Avogadro’s constant NA 6,02 × 1023 mol-1 Avogadro se konstante TABLE 2: FORMULAE/TABEL 2: FORMULES m n m n = M or/of c = V or/of c = MV pH= -log[H3O+] N ca Va na Kw = [H3O+][OH-] = 1x10-14 at /by 298K n= N or/of = A cb Vb nb V n= V m Eθcell = Eθcathode–Eθanode / Eθsel = Eθkatode–Eθanode Eθcell = Eθreduction–Eθoxidation / Eθsel = Eθreduksie–Eθoksidasie Eθcell = Eθoxidising agent–Eθreducing agent / Eθsel = Eθoksideermiddel–Eθreduseermiddel Q Q q =IΔt n= or/of n = e qe Copyright reserved Please turn over Hosted by www.ecexams.co.za.

Downloaded from hlayiso.com (EC/SEPTEMBER 2024) PHYSICAL SCIENCES P2 17 TABLE 3: THE PERIODIC TABLE OF ELEMENTS/TABEL 3: DIE PERIODIEKE TABEL VAN ELEMENTE 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 (I) (II) Atoomgetal (III) (IV) (V) (VI) (VII) (VIII) KEY/ SLEUTEL Atomic number 1 2 H He 2,1 1 29 4 Elektronegatiwiteit Simbool 3 4 Electronegativity 1,9 Cu Symbol 5 6 7 8 9 10 Li Be 63,5 B C N O F Ne 1,0 1,5 2,0 2,5 3,0 3,5 4,0 7 9 11 12 14 16 19 20 11 12 13 14 15 16 17 18 Na Mg Benaderde relatiewe atoommassa Aℓ Si P S Cℓ Ar 0,9 1,2 Approximate relative atomic mass 1,5 1,8 2,1 2,5 3,0 23 24 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 Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr 0,8 1,0 1,3 1,5 1,6 1,6 1,5 1,8 1,8 1,8 1,9 1,6 1,6 1,8 2,0 2,4 2,8 39 40 45 48 51 52 55 56 59 59 63,5 65 70 73 75 79 80 84 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe 0,8 1,0 1,2 1,4 1,8 1,9 2,2 2,2 2,2 1,9 1,7 1,7 1,8 1,9 2,1 2,5 86 88 89 91 92 96 101 103 106 108 112 115 119 122 128 127 131 55 56 57 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tℓ Pb Bi Po At Rn 0,7 133 0,9 137 139 1,6 179 181 184 186 190 192 195 197 201 1,8204 1,8 207 1,9 209 2,0 2,5 87 88 89 Fr Ra Ac 0,7 0,9 226 58 59 60 61 62 63 64 65 66 67 68 69 70 71 Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu 140 141 144 150 152 157 159 163 165 167 169 173 175 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 Copyright reserved Please turn over Hosted by www.ecexams.co.za.

Downloaded from hlayiso.com 18 PHYSICAL SCIENCES P2 (EC/SEPTEMBER 2024) TABLE 4A: STANDARD REDUCTION POTENTIALS TABEL 4A: STANDAARD REDUKSIEPOTENSIALE Half-reactions/Halfreaksies E θ (V) F2(g) + 2e− ⇌ 2F− + 2,87 Co 3+ +e − ⇌ Co 2+ + 1,81 H2O2 + 2H+ +2e− ⇌ 2H2O +1,77 − MnO 4 + 8H+ + 5e− ⇌ Mn2+ + 4H2O + 1,51 Cℓ2(g) + 2e− ⇌ 2Cℓ− + 1,36 2− Cr2O 7 + 14H+ + 6e− ⇌ 2Cr 3+ + 7H2O + 1,33 O2(g) + 4H+ + 4e− ⇌ 2H2O + 1,23 MnO2 + 4H + 2e + − ⇌ Mn 2+ + 2H2O + 1,23 Pt2+ + 2e− ⇌ Pt + 1,20 Br2(ℓ) + 2e− ⇌ 2Br− + 1,07 − ⇌ NO(g) + 2H2O + 0,96 Increasing reducing ability/Toenemende reduserende vermoë NO 3 + 4H+ + 3e− Increasing oxidising ability/Toenemende oksiderende vermoë Hg2+ + 2e− ⇌ Hg(ℓ) + 0,85 Ag+ + e− ⇌ Ag + 0,80 − NO 3 + 2H+ + e− ⇌ NO2(g) + H2O + 0,80 Fe3+ + e− ⇌ Fe2+ + 0,77 O2(g) + 2H + 2e + − ⇌ H2O2 + 0,68 I2 + 2e− ⇌ 2I− + 0,54 + Cu + e − ⇌ Cu + 0,52 SO2 + 4H+ + 4e− ⇌ S + 2H2O + 0,45 2H2O + O2 + 4e− ⇌ 4OH− + 0,40 Cu2+ + 2e− ⇌ Cu + 0,34 2− SO 4 + 4H+ + 2e− ⇌ SO2(g) + 2H2O + 0,17 Cu2+ + e− ⇌ Cu + + 0,16 Sn4+ + 2e− ⇌ Sn2+ + 0,15 S + 2H + 2e + − ⇌ H2S(g) + 0,14 2H+ + 2e− ⇌ H2(g) 0,00 Fe3+ + 3e− ⇌ Fe − 0,06 Pb2+ + 2e− ⇌ Pb − 0,13 Sn 2+ + 2e − ⇌ Sn − 0,14 Ni2+ + 2e− ⇌ Ni − 0,27 Co2+ + 2e− ⇌ Co − 0,28 Cd 2+ + 2e − ⇌ Cd − 0,40 Cr3+ + e− ⇌ Cr2+ − 0,41 Fe2+ + 2e− ⇌ Fe − 0,44 Cr3+ + 3e− ⇌ Cr − 0,74 Zn 2+ + 2e − ⇌ Zn − 0,76 2H2O + 2e− ⇌ H2(g) + 2OH− − 0,83 Cr2+ + 2e− ⇌ Cr − 0,91 Mn2+ + 2e− ⇌ Mn − 1,18 Aℓ 3+ + 3e − ⇌ Aℓ − 1,66 Mg2+ + 2e− ⇌ Mg − 2,36 Na+ + e− ⇌ Na − 2,71 Ca2+ + 2e− ⇌ Ca − 2,87 2+ Sr + 2e − ⇌ Sr − 2,89 Ba2+ + 2e− ⇌ Ba − 2,90 Cs+ + e- ⇌ Cs - 2,92 K+ + e− ⇌ K − 2,93 + Li + e − ⇌ Li − 3,05 Copyright reserved Please turn over Hosted by www.ecexams.co.za.

Downloaded from hlayiso.com (EC/SEPTEMBER 2024) PHYSICAL SCIENCES P2 19 TABLE 4B: STANDARD REDUCTION POTENTIALS TABEL 4B: STANDAARD REDUKSIEPOTENSIALE Half-reactions/Halfreaksies E θ (V) Li+ + e− ⇌ Li − 3,05 K+ + e− ⇌ K − 2,93 Cs+ + e− ⇌ Cs − 2,92 Ba2+ + 2e− ⇌ Ba − 2,90 Sr2+ + 2e− ⇌ Sr − 2,89 Ca2+ + 2e− ⇌ Ca − 2,87 Na+ + e− ⇌ Na − 2,71 Mg2+ + 2e− ⇌ Mg − 2,36 3+ Aℓ + 3e − ⇌ Aℓ − 1,66 Mn2+ + 2e− ⇌ Mn − 1,18 Cr2+ + 2e− ⇌ − 0,91 Increasing reducing ability/Toenemende reduserende vermoë Cr 2H2O + 2e− ⇌ H2(g) + 2OH− − 0,83 Increasing oxidising ability/Toenemende oksiderende vermoë Zn2+ + 2e− ⇌ Zn − 0,76 Cr3+ + 3e− ⇌ Cr − 0,74 Fe2+ + 2e− ⇌ Fe − 0,44 Cr3+ + e− ⇌ Cr2+ − 0,41 Cd2+ + 2e− ⇌ Cd − 0,40 Co2+ + 2e− ⇌ Co − 0,28 Ni2+ + 2e− ⇌ Ni − 0,27 2+ Sn + 2e − ⇌ Sn − 0,14 Pb2+ + 2e− ⇌ Pb − 0,13 Fe3+ + 3e− ⇌ Fe − 0,06 2H+ + 2e− ⇌ H2(g) 0,00 S + 2H+ + 2e− ⇌ H2S(g) + 0,14 Sn4+ + 2e− ⇌ Sn2+ + 0,15 Cu2+ + e− ⇌ Cu+ + 0,16 2− SO 4 + 4H+ + 2e− ⇌ SO2(g) + 2H2O + 0,17 Cu2+ + 2e− ⇌ Cu + 0,34 2H2O + O2 + 4e− ⇌ 4OH− + 0,40 SO2 + 4H+ + 4e− ⇌ S + 2H2O + 0,45 Cu+ + e− ⇌ Cu + 0,52 I2 + 2e− ⇌ 2I− + 0,54 O2(g) + 2H + 2e + − ⇌ H2O2 + 0,68 Fe3+ + e− ⇌ Fe2+ + 0,77 − NO 3 + 2H+ + e− ⇌ NO2(g) + H2O + 0,80 + Ag + e − ⇌ Ag + 0,80 Hg2+ + 2e− ⇌ Hg(ℓ) + 0,85 − NO 3 + 4H+ + 3e− ⇌ NO(g) + 2H2O + 0,96 Br2(ℓ) + 2e − ⇌ 2Br − + 1,07 Pt2+ + 2 e− ⇌ Pt + 1,20 MnO2 + 4H+ + 2e− ⇌ Mn2+ + 2H2O + 1,23 O2(g) + 4H+ + 4e− ⇌ 2H2O + 1,23 2− Cr2O 7 + 14H+ + 6e− ⇌ 2Cr3+ + 7H2O + 1,33 Cℓ2(g) + 2e− ⇌ 2Cℓ− + 1,36 − MnO 4 + 8H+ + 5e− ⇌ 2+ Mn + 4H2O + 1,51 H2O2 + 2H +2 e + − ⇌ 2H2O +1,77 Co3+ + e− ⇌ Co2+ + 1,81 F2(g) + 2e− ⇌ 2F− + 2,87 Copyright reserved Please turn over Hosted by www.ecexams.co.za.