Physical Sciences Grade 12 P2 Mpumalanga November 2014 QP

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE EXAM PHYSICAL SCIENCES P2 SEPTEMBER 2014 GRADE 12 MARKS: 150 TIME: 3 HOURS This paper consists of 17 pages and 4 data sheets

Downloaded from hlayiso.com Physical Science/P2 2 September 2014 NSC INSTRUCTIONS AND INFORMATION 1. Write your name in the appropriate space 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 sub questions, 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. You are advised to use the attached DATA SHEETS. 9. Show ALL formulae and substitutions in ALL calculations. 10. Round off your final numerical answers to a minimum of TWO decimal places. 11. Give brief motivations, discussions, et cetera where required. 12. Write neatly and legibly. Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Science/P2 3 September 2014 NSC QUESTION 1 : MULTIPLE-CHOICE QUESTIONS Four options are provided as possible answers to the following questions. Each question has only ONE correct answer. Choose the answer and write only the letter (A – D) next to the question number (1.1 – 1.10) in the ANSWER BOOK, for example 1.11 E. 1.1 Which ONE of the following compounds is an aldehyde? A Butanol B Butanoic acid C Butane D Butanal (2) 1.2 Ethene can be converted into other carbon-containing compounds using the reactants shown in the following flow chart. HBr NaOH ethene compound X compound Y reaction 1 reaction 2 Compounds X and Y are, respectively: X Y A bromoethane methanol B bromoethane ethanol C bromoethene ethanoic acid D bromoethene ethane hydroxide (2) Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Science/P2 4 September 2014 NSC 1.3 A weak acid HA dissociates in aqueous solution as shown below HA(aq) H+(aq) + A–(aq) ΔH = +20 kJ·mol-1 Which ONE of the following changes will result in an increase in the [H+] of the solution? A Addition of a little aqueous sodium hydroxide solution B Raising the temperature of the solution C Dissolving a little of the sodium salt, NaA, in the solution D Adding a catalyst to the solution (2) 1.4 Cobalt chloride crystals are dissolved in a water/alcohol mixture to form a blue solution as represented by the following equilibrium equation. CoCℓ42- (aq) + 6H2O (ℓ) ⇌ Co(H2O)62+ (aq) + 4Cℓ – (aq) ΔH<0 (blue) (pink) A few drops of concentrated sulphuric acid are added to the above solution. What colour change is observed and what is the reason for the colour change? Colour Reason A Blue H2O molecules are removed B Pink Cℓ – ions are removed C Blue Cℓ – ions are added D No change H2O molecules are added (2) 1.5 In which ONE of the following equilibrium reactions is the yield of products favoured by increasing the pressure by decreasing the volume of the reaction mixture at constant temperature? A 2NO(g) + Cℓ2(g) ⇌ 2NOCℓ(g) B CO(g) + H2O(g) ⇌ CO2(g) + H2(g) C 2SO3(g) ⇌ 2SO2(g) + O2(g) D PCℓ5(g) ⇌ PCℓ3(g) + Cℓ2(g) (2) Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Science/P2 5 September 2014 NSC 1.6 Consider the reversible reaction represented below: CH3COOH(aq) + OH-(aq) ⇌ CH3COO-(aq) + H2O(ℓ) The correct conjugate acid-base pair is: A CH3COOH and H2O B CH3COOH and OH- C CH3COO- and H2O D CH3COOH and CH3COO- (2) 1.7 An aqueous solution that contains more hydronium ions than hydroxide ions is a(n) A basic solution B acidic solution C neutral solution D standardised solution (2) 1.8 According to the Brønsted-Lowry theory, a base …….. A dissociates in aqueous solution B raises the hydrogen ion concentration of an aqueous solution above 1.0 x 10-7 mol.dm-3. C tastes bitter and feels slippery D accepts a proton during a collision with an acid (2) Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Science/P2 6 September 2014 NSC 1.9 Conductor Y is permanently fixed to an aluminium plate as shown in the diagram below. The plate is covered by a piece of filter paper soaked in a KNO3 solution. Point X is moveable and can be brought into contact with any of the clean metal squares arranged on the filter paper covering the aluminium plate. X V Zn Mg Ag Fe KNO3 soaked filter paper Y Aluminium plate The voltmeter will give the highest reading when X is in contact with .............? A Zn B Mg C Ag D Fe (2) 1.10 What will happen at the negative electrode of a voltaic (galvanic) cell and at the negative electrode of an electrolytic cell ? Voltaic (galvanic) cell Electrolytic cell A Oxidation Reduction B Reduction Oxidation C Oxidation Oxidation D Reduction Reduction (2) [ 20] Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Science/P2 7 September 2014 NSC QUESTION 2 : (Start on a new page) Organic chemistry is the chemistry of organic molecules divided into homologous series which are identified by the functional groups. 2.1 Define the term homologous series. (2) 2.2 Consider the organic molecules listed below. H H H H O H C C C C C A hex-2-ene B H H H H H H H O C CH3CHCℓCHCH2 D H C C C O H H H 2.2.1 Draw the structural formulae of a positional isomer of A. (2) 2.2.2 Write down the structural formula of the functional group of B and next to it write down the name of the homologous series to which B belongs. (2) 2.2.3 Write down the IUPAC name for compound C. (2) 2.2.4 Write down the structural formula of ONE functional isomer of compound D (2) [10] Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Science/P2 8 September 2014 NSC QUESTION 3 : (Start on a new page) Damien and Luke carried out an investigation to determine the relationship between the mass of a haloalkane and the boiling point, and obtained the results as shown in the table below. Haloalkane Mass (g·mol-1) Boiling point (K) Fluoromethane 34 194,7 Chloromethane 50,5 248,9 Bromomethane 95 276,7 Iodomethane 142 315,5 3.1 Write the investigative question for their investigation. (2) 3.2 What was their dependent variable? (1) 3.3 What was their independent variable? (1) 3.4 What would need to be kept constant during this investigation? (1) 3.5 Why the variable, that you have named in 3.4 above, must be kept constant? (1) 3.6 What trend in boiling points can be observed from the table? (2) 3.7 Give an explanation for the observed trend. (3) [11] Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Science/P2 9 September 2014 NSC QUESTION 4 : (Start on a new page) 4. 1 Organic reactions are often represented by reaction pathways as represented below. The reactions are labelled from I to VI. IV CH3– CH3 CO2 + H2O I II III CH2 = CH2 CH3– CH2 –Br CH3– CH2 –OH V VI – [CH2 –CH2]n – You are provided with a list of possible organic reactions that may be represented in the above pathway. Addition Elimination Substitution Esterification Polymerisation Combustion / Oxidation 4.1.1 Match the process I to VI with the names of the organic reactions provided above. (6) 4.1.2 Write down the formula of the other reactant that has to be used in reactions I and IV. (2) Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Science/P2 10 September 2014 NSC 4.2 Propyl propanoate is an example of an ester with a chemically tinged pineapple flavour. The apparatus below represents the apparatus used in the laboratory to produce this ester. 4.2.1 Write down the name of the type of reaction that takes place in the above experiment. (1) 4.2.2 Explain why it is so important to add sulphuric acid to the reaction mixture. (2) 4.2.3 State the safety precautions built into the design of the experiment when using the above set-up. (2) 4.2.4 Use structural formulae, to write down a balanced chemical equation for the reaction taking place in the test tube. (5) 4.3 Polymerisation is the formation of macromolecules by joining together a large number of small molecules (monomers). One such process results in the formation of poly-ethene or polythene, first manufactured in 1933. 4.3.1 Name the monomer of polythene. (1) 4.3.2 Identify the functional group of the monomer mentioned in 4.3.1 that (1) makes polymerisation possible. 4.3.3 Write out and explain a practical method you could use to confirm the presence of the functional group you identified in 4.3.2. (2) 4.3.4 Draw a polymer consisting of three monomers of ethene. (2) 4.3.5 Name the type of polymerisation that took place. (1) [25] Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Science/P2 11 September 2014 NSC QUESTION 5 : (Start on a new page) The mining of phosphate rock and its conversion to superphosphate is carried out in South Africa at Phalaborwa, in the Limpopo province, represented by the reaction equation below: Ca3(PO4)2 (s) + 2H2SO4 (aq) → Ca(H2PO4)2 (aq) + 2CaSO4 (s) 5.1 An increase in temperature will increase the rate of the above reaction. List any TWO other factors that will increase its rate. (4) 5.2 The figure below shows the Maxwell-Boltzmann distribution curves for the above reaction at two different temperatures. The activation energy for this reaction is indicated on the graph by the vertical line and labelled as EA. 300 K Number of particles 400 K EA Kinetic energy EA 5.2.1 Define the term, activation energy. (2) 5.2.2 Write down the name of the theory used to explain how reactions occur at the molecular level. (1) 5.2.3 Referring to the shaded areas in the distribution curves provided, use the theory named in QUESTION 5.2.2 to explain why an increase in temperature causes an increase in reaction rate. (3) [10] Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Science/P2 12 September 2014 NSC QUESTION 6 : (Start on a new page) 6.1 In a research laboratory, a mixture of SO2 gas and O2 gas was placed into a closed container at 30°C with a small amount of V2O5. This corresponds to the second step of the Contact Process and SO3 is formed. At certain times, various changes in the physical conditions applicable to the reaction or to the chemicals themselves, were made. A graph of reaction rate versus time was constructed: 6.1.1 Explain what is meant by the term dynamic equilibrium. (2) 6.1.2 Write down a balanced chemical equation for the reaction represented by: (2) (a) The dotted line. (2) (b) The solid line. 6.1.3 At t = 20 s, there was a change in pressure. State whether this change was an INCREASE or a DECREASE in pressure. Give a reason for the answer. (3) 6.1.4 What other change in reaction conditions occurred at t = 40 s? (1) Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Science/P2 13 September 2014 NSC 6.2 0,5 mole hydrogen gas and 0,5 mole oxygen gas are sealed in a 200 cm3 container at temperature of 118 ºC. The following chemical equilibrium is established after a certain time. 2H2 (g) + O2 (g)  2H2O (g) ΔH = -484 kJ Analysis of the equilibrium mixture shows that the mass of oxygen in the container is 9,6 g. Calculate the equilibrium constant for the reaction at this temperature. (7) [17] QUESTION 7 : (Start on a new page) 7.1 A certain species of fish cannot survive in a river where the water has a pH of less than 5,5. The hydrogen ion concentration of the water in the river was measured to be 3,2 x 10-5 mol·dm-3. Will this species of fish survive in the river? Support your answer with a relevant calculation. (4) 7.2 Write down the Brönsted- Lowry definition of an acid. (2) 7.3 The following list of solutions is available in the laboratory: A 0,1 mol·dm-3 HCℓ B 0,2 mol·dm-3 NaOH C 0,5 mol·dm-3 Na2CO3 D 0,5 mol·dm-3 CH3COOH From the above list choose … 7.3.1 a weak base. (1) 7.3.2 a strong acid. (1) 7.3.3 an acid with the highest concentration. (1) [9] Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Science/P2 14 September 2014 NSC QUESTION 8 : (Start on a new page) 8.1 Ethanoic acid (CH3COOH) is a monoprotic acid. 8.1.1 What is meant by the term monoprotic acid? (2) 8.1.2 When ethanoic acid is mixed with water, ions form. Give the chemical formulae of the ions formed. (2) 8.1.3 A solution of CH3COOH of concentration 1 mol·dm-3 conducts electricity but not as readily as a solution of HCℓ of the same concentration. Give a brief explanation for this observation. (2) 8.2 A standard solution of sodium hydroxide is prepared by dissolving exactly 2,5 g of NaOH in enough water to form a 500 cm3 solution. 8.2.1 Calculate the concentration of the solution. (3) 8.2.2 20 cm3 of this solution of sodium hydroxide is titrated with ethanoic acid. The volume of the acid required for the titration is 24,5 cm3. Calculate the concentration of the acid. The chemical equation is: NaOH + CH3COOH  CH3COONa + H2O (3) 8.2.3 Which is the preferred reactant that should be placed in the burette? Explain the answer. (2) 8.2.4 The table below shows some indicators and their pH ranges. Indicator pH range bromothymol blue 6,0 - 7,6 phenolphthalein 8,3 - 10,0 methyl orange 3,1 - 4,4 Select a suitable indicator for this titration and give a reason for the (2) answer. [16] Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Science/P2 15 September 2014 NSC QUESTION 9 : (Start on a new page) The sketch below represents an electro-chemical cell. A suitable light bulb in the external circuit is glowing. The direction of electron flow is indicated. soaked in NaCℓ solution 9.1 Which ONE of the electrodes (Ni or Ag) is the anode of the cell? (1) 9.2 Write down the equation of the reaction taking place in the Ag/Ag+ half-cell. (2) 9.3 Calculate the initial EMF of the cell. (4) 9.4 What does the cotton wool represent and explain its function. (3) 9.5 If 0,4 moles of electrons flow from the anode to the cathode, calculate the decrease in mass of the anode. (4) [14] QUESTION 10 : (Start on a new page) The medal Natasha won for 3nd place in a dancing competition has badly tarnished, and she wishes to coat it with copper. 10.1 Draw a fully annotated diagram indicating the apparatus and chemicals Natasha would use to coat the medal. (6) 10.2 Write down the reduction half reaction which takes place during the coating process. (2) 10.3 Is the medal the anode or the cathode of the cell? (1) [9] Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Science/P2 16 September 2014 NSC QUESTION 11 : (Start on a new page) Nitrogen is a macronutrient which is essential for plant growth and is a vital component of NPK commercial fertilisers. 11.1 A 50 kg bag of NPK fertiliser is labelled 3:2:5(26). Calculate the mass of nitrogen in this bag of fertiliser. (3) 11.2 Give 1 advantage for a farmer of using commercial NPK fertilisers rather than using organic fertilisers such as compost or manure. (1) 11.3 These macronutrients are not available to plants in their elemental form and are manufactured in the form of soluble compounds. The following flow chart outlines the method used to produce ammonium nitrate. It includes the:  The preparation of ammonia.  The preparation of nitric acid.  The reaction of ammonia with nitric acid to produce ammonium nitrate. Air Fractional distillation of liquid air A Ammonia (NH3) C + oxygen (O2) Hydrogen (H2) Nitrogen monoxide (NO) Electrolysis + oxygen (O2) E B Nitrogen dioxide (NO2) D Nitric acid (HNO3) Ammonium nitrate(NH4NO3) Study the above-mentioned flow chart for the manufacturing of ammonium nitrate, and write down the NAME of: 11.3.1 reactant A (1) 11.3.2 reactant B (1) 11.3.3 the industrial process C (1) 11.3.4 reactant D (1) 11.3.5 the industrial process E. (1) [9] GRAND TOTAL: 150 Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences/P2 17 September 2014 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/SIMBOOL VALUE/WAARDE Standard pressure Standaarddruk p 1,013 x 105 Pa Molar gas volume at STP Vm 22,4 dm3∙mol-1 Molêre gasvolume by STD Standard temperature T 273 K Standaardtemperatuur Charge on electron e -1,6 x 10-19C Lading op elektron TABLE 2: FORMULAE/TABEL 2: FORMULES m N n n M NA n m V c OR / OF c  n V MV Vm caVa na  pH = -log[H3O+] cbVb nb Kw = [H3O+][OH-] = 1 x 10-14 at 298 K Eθcell  Eθcathode  Eθanode / Eθsel  Ekatode θ  Eθanode Eθcell  Ereduction θ  Eθoxidation / Eθsel  Ereduksie θ  Eθoksidasie θ θ θ Eθcell  Eoxidising θ θ agent  Ereducingagent / E sel  E oksideermiddel  Ereduseermiddel Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences/P2 18 September 2014 NSC 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) (III) (IV) (V) (VI) (VII) (VIII) 1 2 Atomic number 2,1 H KEY/SLEUTEL Atoomgetal He 1 4 3 4 5 6 7 8 9 10 1,0 Li 1,5 Be Electronegativity 29 Symbol 2,0 B 2,5 C 3,0 N 3,5 O 4,0 F Ne 7 9 Elektronegatiwiteit 1,9 Cu Simbool 11 12 14 16 19 20 11 12 63,5 13 14 15 16 17 18 0,9 Na 1,2 Mg 1,5 Aℓ 1,8 Si 2,1 P 2,5 S 3,0 Cℓ Ar 23 24 Approximate relative atomic mass 27 28 31 32 35,5 40 Benaderde relatiewe atoommassa 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 1,5 Ti 1,6 V 1,6 Cr 1,5 Mn 1,8 Fe 1,8 Co 1,8 Ni 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 1,4 Zr 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 1,6 Hf 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

Physical Sciences/P2 Downloaded from 19 hlayiso.com September 2014 NSC TABLE 4A: STANDARD REDUCTION POTENTIALS TABEL 4A: STANDAARD REDUKSIEPOTENSIALE Half-reactions/Halfreaksies E θ (V) F2(g) + 2e ⇌ 2F + 2,87 Co3+ + 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 ⇌ 2Cr3+ + 7H2O + 1,33 O2(g) + 4H+ + 4e ⇌ 2H2O + 1,23 MnO2 + 4H+ + 2e ⇌ Mn2+ + 2H2O + 1,23 Pt2+ + 2e ⇌ Pt + 1,20 Br2(ℓ) + 2e ⇌ 2Br + 1,07  NO 3 + 4H+ + 3e ⇌ NO(g) + 2H2O + 0,96 Hg2+ + 2e ⇌ Hg(ℓ) + 0,85 Increasing reducing ability/Toenemende reduserende vermoë Ag+ + e ⇌ Ag + 0,80  NO 3 + 2H+ + e NO2(g) + H2O + 0,80 Increasing oxidising ability/Toenemende oksiderende vermoë ⇌ 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 Sn2+ + 2e ⇌ Sn  0,14 Ni2+ + 2e ⇌ Ni  0,27 Co2+ + 2e ⇌ Co  0,28 Cd2+ + 2e ⇌ Cd  0,40 Cr3+ + e ⇌ Cr2+  0,41 Fe2+ + 2e ⇌ Fe  0,44 Cr3+ + 3e ⇌ Cr  0,74 Zn2+ + 2e ⇌ Zn  0,76 2H2O + 2e ⇌ H2(g) + 2OH  0,83 Cr2+ + 2e ⇌ Cr  0,91 Mn2+ + 2e ⇌ Mn  1,18 Aℓ3+ + 3e ⇌ Aℓ  1,66 Mg2+ + 2e ⇌ Mg  2,36 Na+ + e ⇌ Na  2,71 Ca2+ + 2e ⇌ Ca  2,87 Sr + 2e 2+  ⇌ 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

Physical Sciences/P2 Downloaded from 20 hlayiso.com September 2014 NSC 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 Increasing oxidising ability/Toenemende oksiderende vermoë Ca2+ + 2e ⇌ Ca  2,87 Na+ + e Na  2,71 Increasing reducing ability/Toenemende reduserende vermoë ⇌ Mg2+ + 2e ⇌ Mg  2,36 Aℓ3+ + 3e ⇌ Aℓ  1,66 Mn2+ + 2e ⇌ Mn  1,18 Cr2+ + 2e ⇌ Cr  0,91 2H2O + 2e ⇌ H2(g) + 2OH  0,83 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 Sn2+ + 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 ⇌ Mn2+ + 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