Topics in the November 2014 Exam Paper for CHEM1612

Transcription

1 November 2014 Topics in the November 2014 Exam Paper for CHEM1612 Click on the links for resources on each topic N-2: 2014-N-3: 2014-N-4: 2014-N-5: 2014-N-6: 2014-N-7: 2014-N-8: 2014-N-9: 2014-N-10: 2014-N-11: 2014-N-12: 2014-N-13: 2014-N-14: Acids and Bases Complexes Chemical Equilibrium Chemical Kinetics Introduction to Chemical Energetics Introduction to Chemical Energetics Acids and Bases Solutions Introduction to Chemical Energetics Introduction to Chemical Energetics Introduction to Chemical Energetics Acids and Bases Acids and Bases Chemical Equilibrium Radiochemistry Complexes Solubility Complexes Introduction to Colloids and Surface Chemistry Redox Reactions and Introduction to Electrochemistry Redox Reactions and Introduction to Electrochemistry

2 Chemical Kinetics November 2014

3 CC0161(a) 2014-N-1 Page 1 of 24 Confidential SEAT NUMBER: STUDENT ID:. SURNAME:. GIVEN NAMES:.. CHEM1612 Chemistry B (Pharmacy) Final Examination Semester 2, 2014 Time Allowed: Three hours + 10 minutes reading time This examination paper consists of 24 pages INSTRUCTIONS TO CANDIDATES 1. This is a closed book exam. 2. A simple calculator (programmable versions and PDA s not allowed) may be taken into the exam room. Make Model 3. The total score for this paper is 100. The possible score per page is shown in the adjacent table. 4. The paper comprises 30 multiple choice questions and 13 pages of short answer questions. ANSWER ALL QUESTIONS. 5. Follow the instructions on page 2 to record your answers to the multiple choice questions. Use a dark lead pencil so that you can erase errors made on the computer sheet. 6. Answer all short answer questions in the spaces provided on this question paper. Credit may not be given where there is insufficient evidence of the working required to obtain the solution. 7. Take care to write legibly. Write your final answers in ink, not pencil. 8. Numerical values required for any question, standard electrode reduction potentials, a Periodic Table and some useful formulas may be found on the separate data sheet. Page(s) Max Gained Marker MCQ Total 100 Check Total

4 2218(a) 2014-N-2 Page 2 of 24 Explain the following terms or concepts. Lewis base 3 Le Châtelier s principle Heterogeneous catalysis A bar of hot iron with a mass of kg and a temperature of C is plunged into an insulated tank of water. The mass of water was kg and its initial temperature was C. What will the temperature of the resulting system be when it has reached equilibrium? The specific heat capacities of water and iron are J g 1 K 1 and J g 1 K 1, respectively. 3

5 2218(a) 2014-N-3 Page 3 of 24 A mass of g of benzoic acid, C 7 H 6 O 2, underwent combustion in a bomb calorimeter. The heat of combustion of benzoic acid is 3226 kj mol 1. What is the change in internal energy during this reaction? 4 If the heat capacity of the calorimeter is kj K 1, calculate the temperature change that should have occurred in the apparatus. Phenylketonuria is an inherited disorder in which phenylacetic acid, C 6 H 5 CH 2 COOH, (simplified here to HPAc) accumulates in the blood. A study of the acid shows that the ph of a 0.12 M HPAc solution is What is the pk a of phenylacetic acid? 3

6 2218(a) 2014-N-4 Page 4 of 24 The freezing point of a sample of seawater is measured as 2.15 C at 1 atm pressure. Assuming that the concentrations of other solutes are negligible, determine the molality (in mol kg 1 ) of NaCl in this sample. The molal freezing point depression constant for H 2 O is 1.86 C kg mol 1. 3 What is the value of the enthalpy change for the following reaction? MgO(s) + CO 2 (g) MgCO 3 (s) 1 Data: Compound MgO(s) CO 2 (g) MgCO 3 (s) Δ f H / kj mol THE REMAINDER OF THIS PAGE IS FOR ROUGH WORKING ONLY.

7 2218(a) 2014-N-5 Page 5 of 24 Consider the following reaction and associated thermochemical data? 2NO 2 (g) É!!N 2 O 4 (g) 3 Data: Compound NO 2 (g) N 2 O 4 (g) Δ f H / kj mol S / J K 1 mol What is the expression for the equilibrium constant, K c, for this reaction? What are the values of ΔH and ΔS for the reaction? ΔH = ΔS = What is the value of ΔG for the reaction at 298 K? ΔG = THE REMAINDER OF THIS PAGE IS FOR ROUGH WORKING ONLY.

8 2218(a) 2014-N-6 Page 6 of 24 Consider the following reaction: 2N 2 O(g) + 3O 2 (g) 4NO 2 (g) Calculate G for this reaction given the following data. 4NO(g) 2N 2 O(g) + O 2 (g) G = kj mol 1 2NO(g) + O 2 (g) 2NO 2 (g) G = kj mol 1 3 THE REMAINDER OF THIS PAGE IS FOR ROUGH WORKING ONLY.

9 2218(a) 2014-N-7 Page 7 of 24 A sample of hydrofluoric acid (0.10 M, 25.0 ml) is titrated with 0.10 M NaOH. The pk a of hydrofluoric acid, HF, is Calculate the ph at the following four points. before any NaOH is added 7 when half of the HF has been neutralised ph = at the equivalence point ph = after the addition of 37.5 ml of NaOH ph = ph = THIS QUESTION CONTINUES ON THE NEXT PAGE.

10 2218(a) 2014-N-8 Page 8 of 24 Sketch the titration curve. 2 THE REMAINDER OF THIS PAGE IS FOR ROUGH WORKING ONLY.

11 2218(a) 2014-N-9 Page 9 of 24 At 700 C, hydrogen and iodine react according to the following equation. H 2 (g) + I 2 (g) É!!!2HI(g) K c = 49.0 If mol of HI(g) is introduced into a 2.00 L flask at 700 C, what will be the concentration of I 2 (g) at equilibrium? 4 Hydrogen also reacts with sulfur at 700 C: 2H 2 (g) + S 2 (g) É!!!2H 2 S(g) K c = Determine K c for the following overall equilibrium reaction at 700 C. 2I 2 (g) + 2H 2 S(g) É S 2 (g) + 4HI(g)

12 2218(a) 2014-N-10 Page 10 of 24 Write balanced nuclear equations for the following changes. 4 Electron capture by 37 Ar Positron emission by 93 Ru Beta particle emission by 42 K Alpha particle emission by 251 Cf Give the oxidation number of the indicated atom in the following compounds. 2 HNO 2 Compound Atom N Oxidation number NI 3 [Co(NH 3 ) 5 Cl]SO 4 K 3 [CrCl 6 ] N Co Cr Write down the formulas for the following compounds. 2 Compound Formula hexaaquacobalt(ii) carbonate tetraamminecopper(ii) sulfate ammonium hexafluoridoferrate(iii) potassium hexacyanidomanganate(ii) THE REMAINDER OF THIS PAGE IS FOR ROUGH WORKING ONLY.

13 2218(a) 2014-N-11 Page 11 of 24 The K sp of AgBr is The K stab of [Ag(S 2 O 3 ) 2 ] 3 is Calculate the value of the equilibrium constant for the dissolution of AgBr in Na 2 S 2 O 3 solution. 7 Calculate the solubility of AgBr in 2.0 M Na 2 S 2 O 3. The K stab for [Ag(S 2 O 3 ) 2 ] 3 is much greater than the K stab for [Ag(NH 3 ) 2 ] +. Explain why this is so.

14 2218(a) 2014-N-12 Page 12 of 24 Draw sketches of a detergent micelle, a lipid vesicle and a water-in-oil microemulsion. 3 In the electrolytic production of Al, what mass of Al can be deposited in 2.00 hours by a current of 1.8 A? 2 What products would you expect at the anode and the cathode on electrolysis of a 1 M aqueous solution of NiI 2? Explain your answers. 2

15 2218(a) 2014-N-13 Page 13 of 24 An electrochemical cell is consists of 1.0 L half-cells of Fe/Fe 2+ and Cd/Cd 2+ with the following initial concentrations: [Fe 2+ ] = M, [Cd 2+ ] = M. What is the initial E cell at 25 C? 8 What is E cell when [Cd 2+ ] reaches 0.15 M? What is [Cd 2+ ] when E cell reaches V? What are the equilibrium concentrations of both ions? [Cd 2+ ] = [Fe 2+ ] =

16 2218(a) 2014-N-14 Page 14 of 24 At a certain temperature the following data were collected for the reaction shown. 2ICl + H 2 I 2 + 2HCl 4 Experiment Initial [ICl] (mol L 1 ) Initial [H 2 ] (mol L 1 ) Rate of formation of [I 2 ] (mol L 1 s 1 ) Determine the rate law for the reaction. What is the value of the rate constant? THE REMAINDER OF THIS PAGE IS FOR ROUGH WORKING ONLY.

17 2218(a) 2014-N-15 Page 15 of 24 THIS PAGE IS FOR ROUGH WORKING ONLY.

18 CC0161(b) CHEM , Semester 2 Physical constants Avogadro constant, N A = mol 1 Faraday constant, F = C mol 1 Planck constant, h = J s Speed of light in vacuum, c = m s 1 Rydberg constant, E R = J Boltzmann constant, k B = J K 1 DATA SHEET Permittivity of a vacuum, ε 0 = C 2 J 1 m 1 Gas constant, R = J K 1 mol 1 = L atm K 1 mol 1 Charge of electron, e = C Mass of electron, m e = kg Mass of proton, m p = kg Mass of neutron, m n = kg Properties of matter Volume of 1 mole of ideal gas at 1 atm and 25 C = 24.5 L Volume of 1 mole of ideal gas at 1 atm and 0 C = 22.4 L Density of water at 298 K = g cm 3 Conversion factors 1 atm = 760 mmhg = kpa 1 Ci = Bq 0 C = 273 K 1 Hz = 1 s 1 1 L = 10 3 m 3 1 tonne = 10 3 kg 1 Å = m 1 W = 1 J s 1 1 ev = J Decimal fractions Decimal multiples Fraction Prefix Symbol Multiple Prefix Symbol 10 3 milli m 10 3 kilo k 10 6 micro µ 10 6 mega M 10 9 nano n 10 9 giga G pico p tera T

19 CC0161(b) CHEM , Semester 2 Standard Reduction Potentials, E Reaction E / V Co 3+ (aq) + e Co 2+ (aq) Ce 4+ (aq) + e Ce 3+ (aq) MnO 4 (aq) + 8H + (aq) + 5e Mn 2+ (aq) + 4H 2 O Au 3+ (aq) + 3e Au(s) Cl 2 + 2e 2Cl (aq) O 2 + 4H + (aq) + 4e 2H 2 O (+0.82 at ph = 7) Pt 2+ (aq) + 2e Pt(s) MnO 2 (s) + 4H + (aq) + e Mn H 2 O NO 3 (aq) + 4H + (aq) + 3e NO(g) + 2H 2 O Pd 2+ (aq) + 2e Pd(s) Ag + (aq) + e Ag(s) Fe 3+ (aq) + e Fe 2+ (aq) I 2 (aq) + 2e 2I (aq) Cu + (aq) + e Cu(s) Cu 2+ (aq) + 2e Cu(s) BiO + (aq) + 2H + (aq) + 3e Bi(s) + H 2 O Sn 4+ (aq) + 2e Sn 2+ (aq) H + (aq) + 2e H 2 (g) 0 (by definition) Fe 3+ (aq) + 3e Fe(s) 0.04 Pb 2+ (aq) + 2e Pb(s) 0.13 Sn 2+ (aq) + 2e Sn(s) 0.14 Ni 2+ (aq) + 2e Ni(s) 0.24 Cd 2+ (aq) + 2e Cd(s) 0.40 Fe 2+ (aq) + 2e Fe(s) 0.44 Cr 3+ (aq) + 3e Cr(s) 0.74 Zn 2+ (aq) + 2e Zn(s) H 2 O + 2e H 2 (g) + 2OH (aq) 0.83 ( 0.41 at ph = 7) Cr 2+ (aq) + 2e Cr(s) 0.89 Al 3+ (aq) + 3e Al(s) 1.68 Sc 3+ (aq) + 3e Sc(s) 2.09 Mg 2+ (aq) + 2e Mg(s) 2.36 Na + (aq) + e Na(s) 2.71 Ca 2+ (aq) + 2e Ca(s) 2.87 Li + (aq) + e Li(s) 3.04

20 CC0161(b) CHEM , Semester 2 Useful formulas Thermodynamics & Equilibrium ΔU = q + w = q pδv ΔG = ΔH TΔS ΔG = ΔG + RT lnq ΔG = RT lnk Δ univ S = R lnk K Δ H 1 1 K R T T 2 ln = ( ) Acids and Bases pk w = ph + poh = pk w = pk a + pk b = ph = pk a + log{[a ] / [HA]} Radioactivity t ½ = ln2/λ A = λn ln(n 0 /N t ) = λt 14 C age = 8033 ln(a 0 /A t ) years Mathematics If ax 2 + bx + c = 0, then x = ln x = log x Area of circle = πr 2 Surface area of sphere = 4πr 2 Volume of sphere = 4 /3 πr 3 Miscellaneous I A = log I A = εcl 0 2 e E = A 4πε r 0 N A ± 2a 2 b b 4ac Electrochemistry ΔG = nfe Moles of e = It/F E = E (RT/nF) logq = E (RT/nF) lnq E = (RT/nF) logk = (RT/nF) lnk E = E logq (at 25 C) n Gas Laws PV = nrt (P + n 2 a/v 2 )(V nb) = nrt E k = ½mv 2 Kinetics t ½ = ln2/k k = Ae Ea/RT ln[a] = ln[a] o kt k2 Ea 1 1 ln = ( ) k R T T Quantum Chemistry E = hν = hc/λ λ = h/mv E = Z 2 E R (1/n 2 ) Δx Δ(mv) h/4π q = 4πr T 4 T λ = K nm Colligative Properties & Solutions Π = crt P solution = X solvent P solvent c = kp ΔT f = K f m ΔT b = K b m

21 PERIODIC TABLE OF THE ELEMENTS HYDROGEN H HELIUM He LITHIUM Li BERYLLIUM Be BORON B CARBON C NITROGEN N OXYGEN O FLUORINE F NEON Ne SODIUM Na MAGNESIUM Mg ALUMINIUM Al SILICON Si PHOSPHORUS P SULFUR S CHLORINE Cl ARGON Ar POTASSIUM K CALCIUM Ca SCANDIUM Sc TITANIUM Ti VANADIUM V CHROMIUM Cr MANGANESE Mn IRON Fe COBALT Co NICKEL Ni COPPER Cu ZINC Zn GALLIUM Ga GERMANIUM Ge ARSENIC As SELENIUM Se BROMINE Br KRYPTON Kr RUBIDIUM Rb STRONTIUM Sr YTTRIUM Y ZIRCONIUM Zr NIOBIUM Nb MOLYBDENUM Mo TECHNETIUM Tc [98.91] 44 RUTHENIUM Ru RHODIUM Rh PALLADIUM Pd SILVER Ag CADMIUM Cd INDIUM In TIN Sn ANTIMONY Sb TELLURIUM Te IODINE I XENON Xe CAESIUM Cs BARIUM Ba HAFNIUM Hf TANTALUM Ta TUNGSTEN W RHENIUM Re OSMIUM Os IRIDIUM Ir PLATINUM Pt GOLD Au MERCURY Hg THALLIUM Tl LEAD Pb BISMUTH Bi POLONIUM Po [210.0] 85 ASTATINE At [210.0] 86 RADON Rn [222.0] 87 FRANCIUM Fr [223.0] 88 RADIUM Ra [226.0] RUTHERFORDIUM Rf [261] 105 DUBNIUM Db [262] 106 SEABORGIUM Sg [266] 107 BOHRIUM Bh [262] 108 HASSIUM Hs [265] 109 MEITNERIUM Mt [266] 110 DARMSTADTIUM Ds [271] 111 ROENTGENIUM Rg [272] 112 COPERNICIUM Cn [283] 114 FLEROVIUM Fl [289] 116 LIVERMORIUM Lv [293] LANTHANOIDS 57 LANTHANUM La CERIUM Ce PRASEODYMIUM Pr NEODYMIUM Nd PROMETHIUM Pm [144.9] 62 SAMARIUM Sm EUROPIUM Eu GADOLINIUM Gd TERBIUM Tb DYSPROSIUM Dy HOLMIUM Ho ERBIUM Er THULIUM Tm YTTERBIUM Yb LUTETIUM Lu ACTINOIDS 89 ACTINIUM Ac [227.0] 90 THORIUM Th PROTACTINIUM Pa [231.0] 92 URANIUM U NEPTUNIUM Np [237.0] 94 PLUTONIUM Pu [239.1] 95 AMERICIUM Am [243.1] 96 CURIUM Cm [247.1] 97 BERKELLIUM Bk [247.1] 98 CALIFORNIUM Cf [252.1] 99 EINSTEINIUM Es [252.1] 100 FERMIUM Fm [257.1] 101 MENDELEVIUM Md [256.1] 102 NOBELIUM No [259.1] 103 LAWRENCIUM Lr [260.1] CC0161(b) CHEM , Semester 2