CHM 172 Final Examination / Finale Eksamen

Transcription

1 DEPARTMENT OF CHEMISTRY DEPARTEMENT CHEMIE DATE / DATUM: TIME / TYD: 3 hr / uur MARKS / PUNTE: 100 PAGES / BLADSYE: 15 EXAMINERS / Dr. PB Ramatsetse EXTERNAL EXAMINERS / Mrs. BA Castleman EKSAMINATORS Mr. MD Molefe EKSTERNE EKSAMINATORS Prof. WJ Schoeman Mrs. AC Botha CHM 172 Final Examination / Finale Eksamen Surname Van Initials Voorletters Student number Studentenommer Signature Handtekening Marks / Punte Question 1 / Vraag 1 23 Question 2 / Vraag 2 27 Question 3 / Vraag 3 30 SECTION A TOTAL AFDELING A TOTAAL 80 SECTION B / AFDELING B 20 Total / Totaal 100 INSTRUCTIONS Use SIDE 2 of the answer sheet for Section B. All answers in Section A must be given in ink. All calculations must be shown in full. Information pages are attached. ONLY the information pages (p14 & 15) may be carefully removed. Pages 1 to 13 must be submitted together with the multiple choice answer sheet. Use the back of the page if you need more space to answer questions. Clearly indicate this action in your answer. INSTRUKSIES Gebruik KANT 2 van die antwoordblad vir Afdeling B. Alle antwoorde in Afdeling A moet in ink gegee word. Alle berekeninge moet volledig getoon word. Inligtingsblaaie is aangeheg. SLEGS die inligtingsblad (bl 14 & 15) mag versigtig verwyder word. Bladsye 1 tot 13 moet ingehandig word saam met die veelvoudigekeusevrae antwoordblad. Gebruik die agterkant van die bladsy indien jy meer spasie benodig vir die antwoord. Dui hierdie aksie duidelik aan in jou antwoord.

2 Section A Afdeling A Question 1 Vraag Consider the one-electron species, H, He +, and Li 2+ in their ground states. (a) Which atom has the smallest radius? Motivate your answer. [2] [23] 1.1 Beskou die een-elektron spesies, H, He +, en Li 2+ in hulle grondtoestande. (a) Watter atoom het die kleinste radius? Motiveer jou antwoord. [2] (b) Calculate the ionization energy for hydrogen in kj/mol. Hint: To ionize the atom, we must supply sufficient energy to promote the electron from n = 1 to n =. [3] [Answer: kj/mol] (b) Bereken die ionisasie-energie vir waterstof in kj/mol. Wenk: Om die atoom te ioniseer moet ons genoeg energie voorsien om die elektron vanaf n = 1 tot n = op te wek. [3] 1.2 (a) Write the full electron configuration (spdfnotation) of osmium (Os). [2] 1.2 (a) Skryf die volle elektronkonfigurasie (spdf-notasie) vir osmium (Os). [2] (b) Write the shorthand electron configuration (noble gas notation) of osmium. [1] (b) Skryf die afgekorte elektronkonfigurasie (edelgasnotasie) vir osmium. [1] (c) A sample of osmium displays an apparently greater weight than usual when measured in a magnetic balance. How does the electron configuration support this observation? [2] (c) ʼn Osmiummonster vertoon oënskynlik ʼn groter as nornale gewig wanneer dit in ʼn magnetiese balans geweeg word. Hoe ondersteun die elektronkonfigurasie hierdie observasie? [2] 2012 CHM 172 2/15 Universiteit van Pretoria Finale Eksamen

3 1.3 Consider the following two molecules: SeF 2 O 2 and XeF 2 O 2 Fully explain with the aid of annotated (add notes) three-dimensional Lewis structures why they have different molecular geometries. Include all bond angles and name the molecular geometries. [6] 1.3 Beskou die volgende twee molekules: SeF 2 O 2 en XeF 2 O 2 Verduidelik volledig met behulp van drie-dimensionele Lewis strukture en bykomende aantekeninge hoekom hierdie molekules verskillende molekulêre geometrië het. Sluit alle bindingshoeke in en benoem die molekulêre geometrië. [6] 1.4 Carbon tetrachloride and dichloromethane have similar molecular geometries. Explain how the following properties relate to their structure: Boiling point Solubility in water CCl C 0.81 g/l CH 2 Cl C 12.5 g/l Include the three-dimensional structures of the two molecules in your explanation. [4] 1.4 Koolstoftetrachloried en dichlorometaan het soortgelyke molekulêre geometrië. Verduidelik hoe die volgende eienskappe verband hou met hulle struktuur: Kookpunt Oplosbaarheid in water CCl C 0.81 g/l CH 2 Cl C 12.5 g/l Sluit die drie-dimensionele strukture van die twee molekules in wanneer jy verduidelik. [4] 2012 CHM 172 3/15 University of Pretoria Final Examination

4 1.5 Consider the nitryl ion, NO + 2. (a) Write one or more appropriate Lewis linestructures for this ion. [2] 1.5 Beskou die nitrielioon, NO + 2. (a) Skryf een of meer toepaslike Lewis-lynstrukture vir hierdie ioon. [2] (b) Name one familiar compound that is isolectronic with the nitryl ion. [1] (b) Noem een bekende verbinding wat isoelektronies met die nitrielioon is. [1] Question 2 Vraag Calculate the mass of titanium(iv) bromite that contains the same number of bromine atoms as mg disilicon hexabromide. [5] [Answer: g Ti(BrO 2 ) 4 ] [27] 2.1 Bereken die massa van titaan(iv)bromiet wat dieselfde aantal broomatome bevat as mg disilikonheksabromied. [5] 2012 CHM 172 4/15 Universiteit van Pretoria Finale Eksamen

5 2.2 (a) g of a pure sample of a carbonate of manganese produces g of CO 2 during complete thermal decomposition. What is the oxidation state of manganese in this sample? [6] [Answer: Empirical formula is Mn(CO 3 ) 2 ; oxidation state of Mn is+4] 2.2 (a) g van ʼn suiwer monster van ʼn karbonaat van mangaan produseer g CO 2 tydens volledige termiese ontbinding. Wat is die oksidasietoetstand van mangaan in hierdie monster? [6] 2.3 A silver nitrate solution is prepared by dissolving g pure silver nitrate in enough distilled water to make cm 3 solution cm 3 of this solution is then diluted to 1.00 dm 3 with distilled water. A zinc nugget of g is placed in ml of the diluted silver nitrate solution. During the reaction that follows, silver is displaced from the solution by the zinc. Assume no change in volume. (a) Write the balanced equation for this reaction. [1] 2.3 ʼn Silwernitraatoplossing word berei deur suiwer silwernitraat in genoeg gedistilleerde water op te los om cm 3 oplossing te maak cm 3 van hierdie oplossing word dan verdun tot 1.00 dm 3 met gedistilleerde water. ʼn Sinkkorrel van g word in ml van die verdunde silwernitraatoplossing geplaas. Tydens die reaksie wat volg, word silwer uit die oplossing verplaas deur die sink. Aanvaar dat die volume nie verander nie. (a) Skryf die gebalanseerde vergelyking vir die reaksie. [1] (b) Although the conversion of reactants to products is 100%, only 94.65% of the solid product can be collected. Calculate the mass of silver that will be collected. [7] [Answer: g Ag] (b) Alhoewel die omsetting van reagense na produkte 100% is, kan slegs 94.65% van die vaste produk herwin word. Bereken die massa van silwer wat herwin sal word. [7] More space on next page / Meers spasie op volgende bladsy 2012 CHM 172 5/15 University of Pretoria Final Examination

6 (c) Calculate the concentrations of all the ions in solution when the reaction is complete. [4] [Answer: M NO 3 and M Zn 2+ ] (c) Bereken die konsentrasies van al die ione in oplossing wanneer die reaksie voltooi is. [4] 2.4 What is the ph of a hydrochloric acid solution if cm 3 of the acid solution is neutralized by cm 3 of a M barium hydroxide solution. [4] [Answer: ] 2.4 Wat is die ph van ʼn soutsuuroplossing indien cm 3 van die suuroplossing deur cm 3 van ʼn M bariumhidroksiedoplossing geneutraliseer word. [4] 2012 CHM 172 6/15 Universiteit van Pretoria Finale Eksamen

7 Question 3 Vraag 3 Assume enthalpy and entropy stay constant with changing temperatures. Thermodynamic data is given on page 13 (do not detach this page). [30] Aanvaar entalpie en entropie bly konstant met temperatuursverandering. Termodinamiese data word op bladsy 13 gegee (moet dit nie losmaak nie). 3.1 Silver(I) oxide can be formed by the reaction of silver metal and oxygen. 3.1 Silwer(I) oksied kan deur die reaksie van silwer metaal met suurstof gevorm word. 4Ag(s) + O 2 (g) 2Ag 2 O(s) (a) Calculate r G for the reaction at 25 C. [5] (a) Bereken r G vir die reaksie by 25 C. [5] [Answer: 22.6 kj/mol; Question 3.1(a-c) is one of the required questions from Kotz & Treichel] (b) What is the pressure of O 2 in equilibrium with Ag and Ag 2 O at 25 C? [3] [Answer: atm] (b) Wat is die druk van die O 2 wat in ewewig met Ag en Ag 2 O is by 25 C? [3] (c) At what temperature would the pressure of O 2 in equilibrium with Ag and Ag 2 O become equal to 1 bar? [2] [Answer: 196 C] (c) By watter temperatuur sal die druk van die O 2 wat in ewewig is met Ag en Ag 2 O gelyk word aan 1 bar? [2] 2012 CHM 172 7/15 University of Pretoria Final Examination

8 3.2 You have the following standard half-cell ready to be used: S 4 O (aq) S 2 O 3 This half-cell must be combined with a Cr 3+ Cr 2+ half-cell in such a way that the voltaic cell delivers 0.70 V at 25 C. The following salts are available: CrCO 3 ; Cr(NO 3 ) 3 ; CrSO 4 ; Cr(OH) 3 ; KNO 3; CaSO 4 (a) Which two salts will you use to make up the solution for the Cr 3+ Cr 2+ half-cell? [1] 3.2 Jy het die volgende standaard half-sel tot jou beskikking: S 4 O 6 2 (aq) S 2 O 3 2 Hierdie half-sel moet met n Cr 3+ Cr 2+ half-sel gekombineer word op so n wyse dat die voltaïese sel 0.70 V sal lewer by 25 C. Die volgende soute is beskikbaar: CrCO 3 ; Cr(NO 3 ) 3 ; CrSO 4 ; Cr(OH) 3 ; KNO 3; CaSO 4 (a) Watter twee soute sal jy gebruik om die oplossing vir die Cr 3+ Cr 2+ half-sel op te maak? [1] (b) Write the cell reaction and calculate what the ratio of [Cr 3+ ] to [Cr 2+ ] must be in order for this cell to produce 0.70 V. [7] [Answer: to 1] (b) Skryf die selreakise en bereken wat die verhouding van [Cr 3+ ] tot [Cr 2+ ] moet wees vir hierdie sel om 0.70 V te produseer. [7] (c) From your answer in (b), calculate suitable concentrations for [Cr 3+ ] and [Cr 2+ ] and then (c) Uit jou antwoord in (b), bereken geskikte konsentrasies vir [Cr 3+ ] en [Cr 2+ ] en skryf dan die write the cell notation for this cell. [3] selnotasie vir hierdie sel. [3] [Example of a possible answer: Pt Cr 2+ (aq, 1.00 M) Cr 3+ (aq, M) S 4 O 2 6 (aq, 1.00 M) S 2 O 2 3 (aq, 1.00 M) Pt ] 2012 CHM 172 8/15 Universiteit van Pretoria Finale Eksamen

9 3.3 (a) Calculate the maximum electrical work that can be done by the following cell at 25 C: Tl(s) Tl + (aq, 1 M) Pb 2+ (aq, 1 M) Pb(s) [3] [Answer: kj/mol] 3.3 (a) Bereken die maksimum elektriese werk wat deur die volgende sel gelewer kan word by 25 C: Tl(s) Tl + (aq, 1 M) Pb 2+ (aq, 1 M) Pb(s) [3] (b) Determine the standard reduction potential for Tl + (aq) + e Tl(s) [3] [Answer: V; alternative method gives V] (b) Bepaal die standaard reduksiepotensiaal vir Tl + (aq) + e Tl(s) [3] (c) What is the equilibrium constant for this reaction? [3] [Answer: ] (c) Wat is die ewewigskonstante vir hierdie reaksie? [3] 2012 CHM 172 9/15 University of Pretoria Final Examination

10 Section B [20] Afdeling B INSTRUCTIONS 1. Answer the following questions on the computer answer sheet. 2. Use only side 2 of the answer sheet. 3. Only one answer per question is allowed. 4. No marks are considered for unclear answers. It is your responsibility to ensure that the answer sheet is readable by the optical mark reader. All instructions are provided on the answer sheet. 5. The allocation of marks per question may vary, but is indicated at each question. 6. Answers are not marked negatively. Question 1 Mark option J of Question 1 on your computer answer sheet. This is for control purposes only and ensures that you use side 2 of the answer sheet. Question 2 Mark option H of Question 2 if you are certain that you have written your student number in the horizontal row of boxes at the top of the answer sheet and that you have correctly coded each digit vertically. The last column of the student number must be blank. INSTRUKSIES 1. Beantwoord die volgende vrae op die rekenaarantwoordblad. 2. Gebruik slegs kant 2 van die antwoordblad. 3. Slegs een antwoord per vraag is toelaatbaar. 4. Geen punte word oorweeg vir onduidelike antwoorde nie. Dit is u verantwoordelikheid op te sorg dat die antwoordblad leesbaar is vir die optiese merkleser. Alle instruksies is op die antwoordvorm aangebring. 5. Die puntetoekenning per vraag mag varieer en word by elke vraag aangedui. 6. Antwoorde word nie negatief nagesien nie. Vraag 1 Merk opsie J van Vraag 1 op u rekenaarantwoordblad. Dit is slegs vir kontroledoeleindes en verseker dat u kant 2 van die antwoordblad gebruik. Vraag 2 Merk opsie H van Vraag 2 indien u seker is dat u u studentenommer op die rekenaarantwoordblad in die boonste horisontale ry blokkies geskryf het, en dat u elke syfer daarvan vertikaal korrek gekodeer het. Die laaste kolom van die studentenommer moet oop wees. Question 3 [3] What is the diameter of an ultra-thin tungsten wire if 6.0 m of this wire has a mass of mg given that the density of tungsten is g/cm 3? A µm Calculation / Berekening B µm C µm D µm E µm F µm G 1.3 µm H 1.25 µm I µm J None of the above / Geen van bogenoemde Vraag 3 [3] Wat is die deursnit van n ultra-dun wolframdraad indien 6.0 m van hierdie draad n massa van mg het, gegee dat die digtheid van wolfram g/cm 3 is? 2012 CHM /15 Universiteit van Pretoria Finale Eksamen

11 Question 4 [2] Which of the following p 2 configurations (a) should realize the lowest energy? (b) should realize the highest energy? (c) are forbidden? Vraag 4 [2] Watter van die volgende p 2 konfigurasies (a) behoort die laaste energie te realiseer? (b) behoort die hoogste energie te realiseer? ) (c) is verbode? A (a) 4 (b) 2 (c) 1 B (a) 5 (b) 2 (c) 1 C (a) 4 (b) 3 (c) 5 D (a) 3 (b) 4 (c) 5 E (a) 4 (b) 2 (c) 1 & 5 F (a) 3 (b) 1 (c) None/Geen G None of the above / Geen van bogenoemde Question 5 [2] Use your knowledge of the rules for drawing Lewis dot structures and formal charges to predict the most likely structure for HSO 4, the conjugate acid of sulfuric acid. The additional electron for the negative charge is indicated by the o symbol in the structures. Vraag 5 [2] Gebruik u kennis van die reëls vir die teken van Lewis kolstrukture en formele ladings om die mees waarskynlike struktuur vir HSO 4, die gekonjugeerde suur van swaelsuur, te voorspel. Die addisionele elektron vir die negatiewe lading is met die o simbool in die struktuur aangedui. Question 6 [2] Rank the following in order of decreasing ionization energy: Ca 2+, Cl, Cl Vraag 6 [2] Rangskik die volgende in volgorde van afnemende ionisasie energie: Ca 2+, Cl, Cl A Ca 2+, Cl, Cl B Ca 2+, Cl, Cl C Cl, Cl, Ca 2+ D Cl, Ca 2+, Cl E Cl, Cl, Ca 2+ F Cl, Ca 2+, Cl 2012 CHM /15 University of Pretoria Final Examination

12 Question 7 [2] The total number of electrons in a chloride ion with angular momentum quantum number = 2 is Vraag 7 [2] Die totale aantal elektrone in n chloriedioon met draaimomentumkwantumgetal = 2 is A 0 B 1 C 2 D 3 E 4 F 6 G 8 H None of the above / Geen van bogenoemde Question 8 [2] The formula for mercury(ii) thiosulfate is Vraag 8 [2] Die formule vir kwik(ii)tiosulfaat is A Hg 2 S 2 O 3 B HgS 2 O 3 C (Hg 2 ) 2 S 2 O 3 D Hg(S 2 O 3 ) 2 E Hg 2 S 2 O 4 F HgS 2 O 4 G Hg 2 S 2 O 4 H Hg(S 2 O 4 ) 2 I Hg 2 SO 4 J None of the above / Geen van bogenoemde Question 9 [2] The following solutions are added to individual solutions of ammonium sulphate. In which one of the cases will a precipitate form? Vraag 9 [2] Die volgende oplossings word by individuele oplossings van ammoniumsulfaat gevoeg. In welke geval sal daar ʼn presipitaat vorm? A B C D E F magnesium chloride sodium dichromate barium nitrate potassium fluoride A & C None of the above A B C D E F magnesium chloride sodium dichromate barium nitrate potassium fluoride A & C None of the above Question 10 [3] Vraag 10 [3] What mass of ethanol (C 2 H 6 O, g/mol, boiling point 78.3 ) can be evaporated from the heat released (assume all the heat is used for the phase change) by the complete reaction of a g piece of magnesium with hydrochloric acid? Given: vap H (ethanol) = kj/mol (at 78.3 ) Watter massa etanol (C 2 H 6 O, g/mol, kookpunt 78.3 C) kan verdamp van die hitte wat vrygestel word (aanvaar al die hitte word vir die faseverandering gebruik) deur die volledige reaksie van n g stuk magnesium met soutsuur? Gegee: vap H (etanol) = kj/mol (by 78.3 ) Mg(s) + 2HCl(aq) MgCl 2 (aq) + H 2 (g) r H = 459 kj A g Calculation / Berekening B g C g D 1333 g E 5485 g F None of the above / Geen van bogenoemde 2012 CHM /15 Universiteit van Pretoria Finale Eksamen

13 Question 11 [2] Given the two reactions below, determine the enthalpy of formation of MnO 2 (s). 2Al(s) + 3 O 2 2(g) Al 2 O 3 (s) A B C 3468 kj/mol kj/mol kj/mol D E 4Al(s) + 3MnO 2 (s) 3Mn(s) + 2Al 2 O 3 (s) 1590 kj/mol Calculation / Berekening +116 kj/mol F None of the above / Geen van bogenoemde Vraag 11 [2] Gegee die twee reaksies hier onder, bepaal die vormingsentalpie vir MnO 2 (s). H = 1676 kj H = 1792 kj BONUS QUESTION Question 12 [4] Use the reduction potential table to determine the observation at the anode and cathode during the electrolysis of aqueous nickel(ii) bromide. Assume that overpotentials do not play a role. A The cathode will increase in mass while bromine liquid forms at the anode. B The cathode will increase in mass while oxygen gas forms at the anode. C The anode will increase in mass while bromine liquid forms at the cathode. D The anode decreases in mass while oxygen gas forms at the cathode. E The cathode increases in mass while the anode decreases in mass. F Hydrogen gas forms at the anode while oxygen gas forms at the cathode. G Oxygen gas forms at the anode while hydrogen gas forms at the cathode. H None of the above BONUSVRAAG Vraag 12 [4] Gebruik die reduksiepotensiaaltabel om die waarnemings by die anode en katode te bepaal tydens die elektrolise van n waterige nikkel(ii)bromiedoplossing. Aanvaar dat oorpotensiale nie n rol speel nie. A Die katode sal toeneem in massa terwyl broom vloeistof by die anode vorm. B Die katode sal toeneem in massa terwyl suurstofgas by die anode vorm. C Die anode sal toeneem in massa terwyl broom vloeistof by die katode vorm. D Die anode sal afneem in massa terwyl suurstofgas by die katode vorm. E Die katode sal toeneem in massa terwyl die anode se massa afneem. F Waterstofgas vorm by die anode terwyl suurstofgas by die katode vorm. G Suurstofgas vorm by die anode terwyl waterstofgas by die katode vorm. H Geen van bogenoemde. Summary of Answers Section B Question Answer J A A A A B C C F A Thermodynamic Values / Termodinamiese waardes Species f H (kj/mol) ( K) S (J/K mol) ( K) f G (kj/mol) ( K) Ag(s) Ag 2 O(s) O 2 (g) Pb 2+ (aq) Pb(s) Tl + (aq) 32.4 Tl(s) 64.2 H 2 O 2 (l) H 2 O(l) H 2 O(g) CHM /15 University of Pretoria Final Examination

14 INLIGTINGSBLAD / INFORMATION PAGE DIE PERIODIEKE TABEL VAN ELEMENTE THE PERIODIC TABLE OF THE ELEMENTS 1 Key / Sleutel 74 Atomic number / Atoomgetal 2 H W Element symbol / Element simbool He Relative Atomic mass / Relatiewe atoommassa (u) Electronegativity / Elektronegatiwiteit Li Be B C N O F Ne Na Mg Al Si P S Cl Ar K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn Fr Ra Ac Rf Db Sg Bh Hs Mt Ds Rg Cn Fl Lv Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr Vergelykings / Equations V = πr 2 h (cylinder / silinder) E = hv E n = Rhc Z2 n 2 E = RhcZ n fin λ = h mv ph = log [H 3 O + ] ph + poh = 14 ΔU = q + w 2 n init q = mcδt r H o = nδ f H o (prod) mδ f H o (react) r S o = ns o (prod) ms o (react) r G o = nδ f G o (prod) mδ f G o (react) o ΔS univ o S surr o o = ΔS sys + ΔS surr = q surr T = H o sys T Δ r G o = Δ r H o TΔ r S o Δ r G = Δ r G o + RTlnQ w max = nfe Δ r G o = nfe o Δ r G o = RTlnK E = E o RT nf lnq E = E o logq (25 C) n logk eq = neo (25 C) lnk = 2.303logK lnq = 2.303logQ Konstante / Constants h = J s R = m -1 c = m s -1 N A = F = x 10 4 C mol 1 e = x C of/or J V 1 mol 1 0 C = K C (H 2 O(l)) = J g 1 K 1 C (H 2 O(s)) = 2.06 J g 1 K 1 C (H 2 O(g)) = 1.92 J g 1 K 1 fus H o (water) = 6.01 kj mol 1 vap H o (water) = kj mol 1 Gas constant / gaskonstante, R: = L atm mol 1 K 1 = J mol 1 K 1 = kpa L mol -1 K -1 = mm Hg L mol -1 K -1 Omsettingsfaktore / Conversion Factors 1 u = g 1 L = 10 3 m 3 = 1 dm 3 1 bar = x 10 5 Pa 1 C = 1 Amp 1 sec 1 inch = 2.54 cm 1 ft = 12 inches 1 yard = 3 feet 1 duim = 2.54 cm 1 voet = 12 duim 1 tree = 3 voet 1 cal = J 1 J = cal = 1 Pa m 3 = 1 m 2 kg s 2 = 1 V C = 1 Watt 1 sec 1 atm = x 10 5 N m 2 = x 10 5 Pa = 760 mm Hg = 760 torr Ewewig / Equilibrium By ewewig: aa(aq) + bb(aq) cc(aq) + dd(aq) aa(aq) + bb(aq) cc(aq) + dd(aq) At equilibrium: E = 0 and Q = K K c of/or Q = [C]c [D] d [A] a [B] b K p of/or Q = P C c d P D P a b A P B Liquids and solids are given a value of 1 unit in the Q and K expressions For insoluble salts / Vir onoplosbare soute M m X x (s) mm x+ (aq) + xx m (aq) K sp = [M x+ ] m [X m ] x CHM 172 INFORMATION PAGE (1) University of Pretoria 2012 INLIGTINGSBLAD (1) Universiteit van Pretoria

15 Standard Reduction Potentials in Aqueous, Acidic or Basic Solution at 25 C Standaard Reduksie Potensiale in Waterige, Suur- of Basiese Oplossing by 25 C... Reduction Half-Reaction / Reduksie Half-Reaksie E (V)* F2 (g) + 2 e 2F (aq) H2O2 (aq) + 2 H + (aq) + 2 e 2 H2O (l) PbO2 (s) + SO (aq) + 4 H + (aq) + 2 e PbSO4 (s) + 2 H2O (l) MnO (aq) + 8 H + (aq) + 5 e Mn 2+ (aq) + 4 H2O (l) Au 3+ (aq) + 3 e Au (s) Cl2 (g) + 2 e 2 Cl (aq) Cr2O7 2- (aq) + 14 H + (aq) + 6 e 2 Cr 3+ (aq) + 7H2O (l) O2 (g) + 4 H + (aq) + 4 e 2 H2O (l) Br2 (l) + 2 e 2 Br (aq) NO (aq) + 4 H + (aq) + 3 e NO (g) + 2 H2O (l) OCl (aq) + H2O (l) + 2 e Cl (aq) + 2 OH (aq) Hg 2+ (aq) + 2 e Hg (l) Ag + (aq) + e Ag (s) Hg + (aq) + 2 e 2 Hg (l) Fe 3+ (aq) + e Fe 2+ (aq) I2 (s) + 2 e 2 I (aq) O2 (g) + 2 H2O (l) + 4 e 4 OH (aq) Cu 2+ (aq) + 2 e Cu (s) S4O6 2 (aq) + 2e 2S2O3 2 (aq) Sn 4+ (aq) + 2 e Sn 2+ (aq) H + (aq) + 2 e H2 (g) 0.00 Pb 2+ (aq) + 2 e Pb (s) Sn 2+ (aq) + 2 e Sn (s) 0.14 Ni 2+ (aq) + 2 e Ni (s) 0.25 V 3+ (aq) + e V 2+ (aq) PbSO4 (s) + 2 e Pb (s) + SO (aq) Cd 2+ (aq) + 2 e Cd (s) Fe 2+ (aq) + 2 e Fe (s) 0.44 Cr 3+ (aq) + e Cr 2+ (aq) Zn 2+ (aq) + 2 e Zn (s) H2O (l) + 2 e H2 (g) + 2 OH aq) [Zn(CN)4] 2- (aq) + 2 e Zn (s) + 4 CN (aq) 1.26 Al 3+ (aq) + 3 e Al (s) 1.66 Mg 2+ (aq) + 2 e Mg (s) 2.37 Na + (aq) + e Na (s) K + (aq) + e K (s) Li + (aq) + e Li (s) *Versus the standard hydrogen electrode / Teen die standaard waterstofelektrode CHM 172 INFORMATION PAGE (2) University of Pretoria 2012 INLIGTINGSBLAD (2) Universiteit van Pretoria 2 4