Physical Sciences Grade 11 P2 Eastern Cape November 2019 QP

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE GRADE 11 NOVEMBER 2019 PHYSICAL SCIENCES P2 (CHEMISTRY) (EXEMPLAR) MARKS: 150 TIME: 3 hours This question paper consists of 17 pages, including 4 datasheets.

Downloaded from hlayiso.com 2 PHYSICAL SCIENCES P2 (EC/NOVEMBER 2019) INSTRUCTIONS AND INFORMATION 1. Write your full NAME and SURNAME in the appropriate spaces on the ANSWER BOOK. 2. This question paper consists of TEN 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

Downloaded from hlayiso.com (EC/NOVEMBER 2019) 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 D. 1.1 Which ONE of the bonds below will have the SHORTEST bond length? A C–O B C–N C C–F D C – Br (2) 1.2 When sulphuric acid reacts with water, the temperature of the reaction mixture increases. Which ONE of the following correctly describes the heat of the reaction (∆H) between sulphuric acid and water from the graph below? P3 Potential energy P2 P1 A P3 – P2 B P1 – P2 C P3 – P1 D P2 – P1 (2) 1.3 Substance P is soluble in substance R. Which ONE of the following most likely represents P and R? P R A HCℓ CCℓ4 B HCℓ H2O C NaCℓ CCℓ4 D I2 H2O (2) Copyright reserved Please turn over

Downloaded from hlayiso.com 4 PHYSICAL SCIENCES P2 (EC/NOVEMBER 2019) 1.4 The boiling points of three compounds are given in the table shown below. Compound Boiling point (K) Cℓ2 238 Br2 332 I2 457 The increase in boiling point from top to bottom of the table is due to an increase in the strength of … A London forces. B ion-dipole forces. C dipole-dipole forces. D hydrogen bonds. (2) 1.5 The pV vs p sketch graphs for four gases, He, CO, CH4, and an ideal gas are shown below. Which sketch graph CORRECTLY shows the pV vs p relationship for He? SKETCH GRAPHS OF pV vs p VALUES A B C pV (J) D p (Pa) (2) 1.6 Consider the following acid-base reaction. HCℓ + NH3 → NH4+ + Cℓ- Which pair of substances represents a conjugate acid-base pair? A HCℓ and NH3 B NH4+ and Cℓ- C HCℓ and Cℓ- D HCℓ and NH4+ (2) Copyright reserved Please turn over

Downloaded from hlayiso.com (EC/NOVEMBER 2019) PHYSICAL SCIENCES P2 5 1.7 Which ONE of the quantities given below is defined as follows? A measure of the average kinetic energy of gas particles. A Volume B Enthalpy C Pressure D Temperature (2) 1.8 5 grams of each of the salts given below is completely dissolved in water to make 100 cm3 of solution at 30 °C. Which salt solution will have the highest concentration of sodium ions (Na +)? A NaCℓ(aq) B Na2CO3(aq) C Na2SO4(aq) D NaHCO3(aq) (2) 1.9 Consider the following redox reaction: Zn (s) + Cu2+(aq) → Zn2+(aq) + Cu (s) Electrons are transferred from … A Zn (s) to Zn2+(aq). B Cu2+(aq) to Cu (s). C Zn(s) to Cu2+(aq). D Zn2+(aq) to Cu (s). (2) 1.10 The oxidation number of sulphur (S) in HSO4- is … A -2. B +6. C +1. D +4. (2) [20] Copyright reserved Please turn over

Downloaded from hlayiso.com 6 PHYSICAL SCIENCES P2 (EC/NOVEMBER 2019) QUESTION 2 (Start on a new page.) Study the molecules given below and answer the questions that follow. CCℓ4, NH3, HCN, H2S and OF2 2.1 Define the term molecule. (2) 2.2 Use the VSERP model to predict the molecular geometry of the following: 2.2.1 CCℓ4 (1) 2.2.2 NH3 (1) 2.3 Draw the Lewis structures for the following molecules: 2.3.1 OF2 (2) 2.3.2 HCN (2) 2.4 Explain why it is possible for NH3 to form a dative covalent bond with H+ but it is not possible for CCℓ4 to form a dative covalent bond with H+. (2) 2.5 Is the H2S molecule POLAR or NON-POLAR? Explain the answer. (4) [14] Copyright reserved Please turn over

Downloaded from hlayiso.com (EC/NOVEMBER 2019) PHYSICAL SCIENCES P2 7 QUESTION 3 (Start on a new page.) The boiling points of the hydrogen halides and group 4 hydrogen compounds are compared in the graph below. 350 Boiling point (K) HF 300 HI 250 HBr HCℓ 200 SnH4 150 CH4 GeH4 SiH4 100 2 3 4 5 Period 3.1 Define boiling point. (2) 3.2 Write down the boiling point of HCℓ. (1) 3.3 Explain why the boiling points of the hydrogen halides are higher than those of corresponding group 4 hydrides from period 3 to 5, by referring to the type of intermolecular forces present in these compounds and energy involved. (4) HF is the halide with the HIGHEST boiling point. 3.4 Write down the name of the intermolecular force present in HF responsible for the high boiling point. (2) 3.5 Which one of HBr and GeH4 will have the highest vapour pressure? Give a reason for the answer by referring to data in the graph. (2) [11] Copyright reserved Please turn over

Downloaded from hlayiso.com 8 PHYSICAL SCIENCES P2 (EC/NOVEMBER 2019) QUESTION 4 (Start on a new page.) 4.1 An experiment was conducted to investigate the relationship between pressure and volume of a fixed gas at a constant temperature of 20,5 °C. The following graph was obtained from the results. GRAPH OF VOLUME VS PRESSURE Volume (cm3) Pressure (kPa) 4.1.1 Write down the name of the law which formulates the pressure- volume relationship shown by the graph. (1) For the investigation write down the: 4.1.2 Investigative question (2) 4.1.3 Controlled variable (1) 4.1.4 Explanation for the relationship between pressure and volume as shown by the graph using the Kinetic Molecular Theory. (3) 4.2 The experiment is repeated at a different temperature. The results of the experiment are plotted on the same axis. Experiment 1 Volume (cm3) Experiment 2 Pressure (kPa) 4.2.1 Which experiment (1 or 2) was carried out at a HIGHER temperature? Explain your answer. (3) Copyright reserved Please turn over

Downloaded from hlayiso.com (EC/NOVEMBER 2019) PHYSICAL SCIENCES P2 9 4.2.2 Give a reason why real gases deviate from ideal gas behaviour at high pressure. (2) 4.3 The diagram below shows the apparatus that is used to demonstrate the relationship between pressure and temperature at constant volume. kPa Jollybulb Thermometer A certain gas is trapped inside the Jolly bulb. At temperature 25 °C the gas exerts a pressure of 101 kPa. The water-bath is then heated to a temperature of 60 °C. 4.3.1 Write down the name of the law which is studied using the above apparatus. (1) 4.3.2 Calculate the reading on the pressure gauge at 60 °C. (4) The water-bath is heated to temperatures higher than 60 °C. It is observed that after some time, while the water-bath is being heated, the reading on the pressure gauge remains constant. 4.3.3 At what temperature is the water in the water-bath when the reading on the pressure gauge remains constant? (1) [18] QUESTION 5 (Start on a new page.) In 1783 Jacques Charles filled an air-balloon with 2 600 g of diatomic gas X. The pressure of the gas was 100 × 103 Pa at a temperature of 23 °C and it occupied a volume of 31,98 m3. 5.1 Give the term for a gas that obeys the general gas equation pV = kT under all pressure and temperature conditions. (1) 5.2 Determine, by calculation, the FORMULA of the gas. (7) [8] Copyright reserved Please turn over

Downloaded from hlayiso.com 10 PHYSICAL SCIENCES P2 (EC/NOVEMBER 2019) QUESTION 6 (Start on a new page.) The diagram shows the potential energy changes during the following chemical reaction: 2 H2 (g) + Cℓ2 (g) → 2 HCℓ (g) Potential energy (kJ·mol-1) 679,1 kJ·mol-1 184,7 kJ·mol-1 Time 6.1 Define activation energy. (2) 6.2 Is the reaction EXOTHERMIC or ENDOTHERMIC? Give a reason for the answer. (2) 6.3 What is the total bond energy (H2 and Cℓ2) of the reactants? Give a reason for the answer. (3) 6.4 Determine the energy released by the bond formation of the HCℓ molecule. (3) 6.5 What effect will the addition of a catalyst have on the value 184,7 kJ·mol -1? Write down only INCREASE, DECREASE or NO EFFECT. Give a reason for the answer. (2) [12] Copyright reserved Please turn over

Downloaded from hlayiso.com (EC/NOVEMBER 2019) PHYSICAL SCIENCES P2 11 QUESTION 7 (Start on a new page.) 7.1 The chemical composition of a particular compound is: 11,79% Carbon 69,57% Chlorine 18,64% Fluorine The molar mass of the compound is 204 g·mol-1. Determine, by calculations, the molecular formula of the compound. (7) 7.2 When heated, lithium reacts with nitrogen to form lithium nitride. The balanced equation: 6 Li (s) + N2 (g) → 2 Li3N (s) 12,3 g of lithium is heated with 33,6 g of N2. 7.2.1 Define the term limiting reagent. (2) 7.2.2 Determine by calculation which substance is the limiting reagent. (6) The actual yield of Li3N in the above reaction is 5,89 g. 7.2.3 Calculate the percentage yield of Li3N. (5) [20] QUESTION 8 (Start on a new page.) 8.1 Sulphuric acid (H2SO4) can react with water through a multistep reaction. The two reactions below show the multistep reaction. (I) H2SO4 (aq) + H2O (ℓ) ⇌ HSO4- (aq) + H3O+ (aq) (II) HSO4- (aq) + H2O (ℓ) ⇌ SO42- (aq) + H3O+ (aq) 8.1.1 Define an acid according to the Lowry-Bronsted model. (2) 8.1.2 Is water acting as a base or an acid in reactions I and II? Give a reason for the answer. (2) 8.1.3 Write down the chemical formula of the substance that acts as an ampholyte in the above reactions. (2) 8.1.4 Write down a balanced chemical equation for the reaction between sulphuric acid and sodium hydrogen carbonate. (3) Copyright reserved Please turn over

Downloaded from hlayiso.com 12 PHYSICAL SCIENCES P2 (EC/NOVEMBER 2019) 8.2 An eggshell contains calcium carbonate (CaCO3) and impurities. An EXCESS amount of a standard dilute acetic acid solution (CH3COOH) of concentration 0,5 mol·dm-3 and volume 250 cm3 is allowed to react COMPLETELY with an eggshell of mass 56 g. The equation for the reaction is given by the balanced equation shown below: 2 CH3COOH (aq) + CaCO3 (s) → Ca(CH3COO)2 (aq) + H2O (ℓ) + CO2 (g) The acetic acid that remained unreacted is neutralised by 25 cm3 of sodium hydroxide (NaOH) with a concentration of 0,968 mol·dm-3 . The equation for the reaction is given by the balanced equation below: CH3COOH (aq) + NaOH (aq) → CH3COONa (aq) + H2O (ℓ) 8.2.1 Define a standard solution. (2) 8.2.2 Calculate the percentage of calcium carbonate (CaCO3) in the egg shell. (10) [21] QUESTION 9 (Start on a new page.) The reaction between magnesium metal and hydrochloric acid is an example of a redox reaction. The balanced equation is: Mg (s) + 2 HCℓ (aq) → MgCℓ2 (aq) + H2 (g) 9.1 Define oxidation in terms of electron transfer. (2) 9.2 Write down the FORMULA or SYMBOL of a substance whose oxidation number does NOT CHANGE during the reaction. (2) 9.3 Write down the symbol of the reducing agent. Explain the answer in terms of oxidation numbers. (3) 9.4 Write down the balanced reduction-half reaction. (2) In another redox reaction Fe2+ is oxidised to Fe3+ ions by dichromate ions (Cr2O72-) in an acidic medium. The dichromate ions (Cr2O72-) are reduced to Cr3+ ions. 9.5 Write down the balanced equation for the net redox reaction by using the ion-electron method. (Show ALL steps in the balancing of the equation.) (7) [16] Copyright reserved Please turn over

Downloaded from hlayiso.com (EC/NOVEMBER 2019) PHYSICAL SCIENCES P2 13 QUESTION 10 (Start on a new page.) The flow diagram below shows the purification process of gold in the mining industry. X Y Z Gold Gold solutions Gold Pure gold Ore (Au+) precipitate 10.1 Give the name of the location in South Africa where the gold-rich ore is mined. (1) The reaction for process X is: 4 Au + 8 NaCN + O2 + 2 H2O → 4 NaAu(CN)2 + 4 NaOH 10.2 Classify the above reaction as REDOX, ACID-BASE or PRECIPITATION reaction. Give a reason for the answer in terms of oxidation numbers. (2) 10.3 Write down the name of the metal used in process Y in the recovery of gold. (2) Process Y is out-dated and the metal named in QUESTION 10.3 is replaced in the modern recovery method of gold. 10.4 Write down the name of the new substance used in process Y. (2) 10.5 Why is an extremely (very) high temperature needed in process Z? (3) [10] TOTAL: 150 Copyright reserved Please turn over

Downloaded from hlayiso.com 14 PHYSICAL SCIENCES P2 (EC/NOVEMBER 2019) NATIONAL SENIOR CERTIFICATE NASIONALE SENIOR SERTIFIKAAT DATA FOR PHYSICAL SCIENCES GRADE 11 PAPER 2 (CHEMISTRY) GEGEWENS VIR FISIESE WETENSKAPPE GRAAD 11 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+] Kw = [H3O+][OH-] = 1x10-14 N ca Va na 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 Copyright reserved Please turn over

Downloaded from hlayiso.com (EC/NOVEMBER 2019) PHYSICAL SCIENCES P2 15 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 2,1 H He 1 29 4 Elektronegatiwiteit Simbool 3 4 1,9 Cu 5 6 7 8 9 10 Symbol 1,0 Li 1,5 Be Electronegativity 63,5 2,0 B 2,5 C 3,0 N 3,5 O 4,0 F Ne 7 9 11 12 14 16 19 20 11 12 13 14 15 16 17 18 0,9 Na 1,2 Mg Benaderde relatiewe atoommassa 1,5 Aℓ 1,8 Si 2,1 P 2,5 S 3,0 Cℓ Ar Approximate relative atomic mass 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 0,8 K 1,0 Ca 1,3 Sc 1,5Ti 1,6 V 1,6 Cr 1,5 Mn 1,8 Fe 1,8 Co 1,8Ni 1,9 Cu 1,6 Zn 1,6 Ga 1,8 Ge 2,0 As 2,4 Se 2,8 Br Kr 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 0,8 Rb 1,0 Sr 1,2 Y 1,4Zr Nb 1,8 Mo 1,9 Tc 2,2 Ru 2,2 Rh 2,2 Pd 1,9 Ag 1,7 Cd 1,7 In 1,8 Sn 1,9 Sb 2,1 Te 2,5 I Xe 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 0,7 Cs 0,9 Ba La 1,6Hf Ta W Re Os Ir Pt Au Hg 1,8 Tℓ 1,8 Pb 1,9 Bi 2,0 Po 2,5 At Rn 133 137 139 179 181 184 186 190 192 195 197 201 204 207 209 87 88 89 0,7 Fr 0,9 Ra Ac 58 59 60 61 62 63 64 65 66 67 68 69 70 71 226 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

Downloaded from hlayiso.com 16 PHYSICAL SCIENCES P2 (EC/NOVEMBER 2019) TABLE 4A: STANDARD REDUCTION POTENTIALS TABEL 4A: STANDAARD REDUKSIEPOTENSIALE Half-reactions/Halfreaksies E θ (V) F2(g) + 2e− ⇌ 2F− + 2,87 Co 3+ +e − ⇌ Co2+ + 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− ⇌ Mn2+ + 2H2O + 1,23 Pt 2+ + 2e − ⇌ Pt + 1,20 Br2(ℓ) + 2e− ⇌ 2Br− + 1,07 − NO 3 + 4H+ + 3e− ⇌ Increasing reducing ability/Toenemende reduserende vermoë NO(g) + 2H2O + 0,96 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 Fe 3+ +e − ⇌ Fe 2+ + 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 Cu 2+ + 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 Pb 2+ + 2e − ⇌ Pb − 0,13 Sn2+ + 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 Ca 2+ + 2e − ⇌ Ca − 2,87 Sr2+ + 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

Downloaded from hlayiso.com (EC/NOVEMBER 2019) PHYSICAL SCIENCES P2 17 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 2+ Mg + 2e − ⇌ Mg − 2,36 Aℓ3+ + 3e− ⇌ Aℓ − 1,66 Mn2+ + 2e− ⇌ Mn − 1,18 ⇌ Increasing reducing ability/Toenemende reduserende vermoë Cr2+ + 2e− Cr − 0,91 2H2O + 2e− ⇌ H2(g) + 2OH− − 0,83 Increasing oxidising ability/Toenemende oksiderende vermoë Zn2+ + 2e− ⇌ Zn − 0,76 Cr3+ + 3e− ⇌ Cr − 0,74 2+ Fe + 2e − ⇌ Fe − 0,44 Cr3+ + e− ⇌ Cr2+ − 0,41 Cd2+ + 2e− ⇌ Cd − 0,40 Co2+ + 2e− ⇌ Co − 0,28 Ni2+ + 2e− ⇌ Ni − 0,27 Sn2+ + 2e− ⇌ Sn − 0,14 2+ Pb + 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 2+ Cu + 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 2+ Hg + 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− ⇌ 3+ 2Cr + 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 3+ Co + e − ⇌ Co 2+ + 1,81 F2(g) + 2e− ⇌ 2F− + 2,87 Copyright reserved Please turn over