CHEM1310_FinalW10_PartA_wAnswers

CHEM1310_FinalW10_PartA_wAnswers - THE UNIVERSITY OF...

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Unformatted text preview: THE UNIVERSITY OF MANITOBA April 17 2010 FINAL EXAMINATION PAGE NO: 1 of 2 Data Pages DEPARTMENT & COURSE NO: CHEM 1310 TIME: 3 HOURS EXAMINATION: University I Chemistry: Intro. to Phys. Chem. EXAMINER: CHEM 1310 Committee IA 1 H 1.008 IIA 3 4 Li Be 6.941 9.0122 11 12 Na Mg 22.990 24.305 VIIIA 2 He IIIA IVA VA VIA VIIA 4.003 5 6 7 8 9 10 B C N O F Ne 10.81 12.011 14.007 15.999 18.998 20.179 atomic number Symbol atomic mass IIIB IVB VB VIB VIIB VIIIB IB IIB 19 20 21 22 23 24 25 26 27 28 29 30 K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn 39.098 40.08 44.956 47.88 50.942 51.996 54.938 55.847 58.933 58.69 63.546 65.38 37 38 39 40 41 42 Rb Sr Y Zr Nb Mo 85.468 87.62 88.906 91.22 92.906 95.94 43 Tc (98) 13 14 15 16 17 18 Al Si P S Cl Ar 26.982 28.086 30.974 32.06 35.453 39.948 31 Ga 69.72 32 33 34 35 36 Ge As Se Br Kr 72.59 74.922 78.96 79.904 83.80 44 45 46 47 48 49 50 51 52 53 54 Ru Rh Pd Ag Cd In Sn Sb Te I Xe 101.07 102.91 106.42 107.87 112.41 114.82 118.69 121.75 127.60 126.90 131.29 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 132.91 137.33 138.91 178.49 180.95 183.85 186.21 190.2 192.22 195.08 196.97 200.59 204.38 207.2 208.98 (209) (210) (222) 87 88 89 Fr Ra Ac (223) 226.03 227.03 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 140.12 140.91 144.24 (145) 150.36 151.96 157.25 158.93 162.50 164.93 167.26 168.93 173.04 174.97 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 232.04 231.04 238.03 237.05 (244) (243) (247) (247) (251) (252) (257) (258) (259) (260) You may tear off this page. Please note there are useful equations given on the back of this page For rough work use the two blank pages found at the back of Part A of the exam. PHYSICAL CONSTANTS CONVERSION FACTORS Avogadro’s number N = 6.022 × 1023 mol–1 101.3 kPa = 1.00 atm Charge on proton e = 1.602 × 10–19 C 1.00 atm = 760 torr or 760 mmHg Gas constant R = 0.0821 L atm K–1 mol–1 ln(x) = 2.303 log(x) R = 8.314 J K–1 mol–1 1 V = 1 J C–1 Planck’s constant h = 6.626 × 10–34 J s 1 kPa L = 1 J Speed of light c = 2.998 × 108 m s–1 1 J = 1 kg m2 s–2 Mass of electron me = 9.11 × 10–28 g 1 Cal = 1000 cal = 4.184 kJ Mass of proton mp = 1.673 × 10–24 g 1 L = 1000 cm3 Mass of neutron mn = 1.675 × 10–24 g 1 bar = 100.0 kPa 0.00 ºC = 273.15 K OTHER USEFUL DATA: Density of water = 1.00 g cm-3, Specific heat of water = 4.184 J K–1 g–1 Kw(25 ºC) = 1.0 x 10-14, ΔHfusion of water = 6.01 kJ/mol ΔHvap of water = 40.7 kJ/mol CHEM 1310 University I Chemistry: Intro. to Phys. Chem. FINAL EXAM SOME USEFUL EQUATIONS For ax 2 + bx + c = 0 solutions are x = − Page: 2 of 2 Data Pages b b 2 − 4ac ± 2a 2a PV=nRT PX V = nX RT ΔE = q + w ΔG = ΔH – T ΔS ΔGo = –R T ln(K) ΔG = ΔGo + RT ln(Q) q = Cs m ΔT w = –Pext ΔV At constant pressure, ΔE = ΔH + w Kp = Kc (RT)Δngas ΔS surr. = − ΔH sys T H=E+PV ln( K 2 ) = ln( K1 ) – ⎛ P2 ⎞ –ΔH vap ⎛ 1 1⎞ – ln ⎜ ⎟ = ⎜ ⎟ R ⎝P ⎠ ⎝ T2 T1 ⎠ 1 ΔH ⎛ 1 1⎞ –⎟ ⎜ R ⎝ T 2 T1 ⎠ zero order half-life: t1 / 2 = Integrated zero order rate law: [A]t = [A]o – kt ⎛ [A ] ⎞ t Integrated first order rate law: ln ⎜ ⎜ [A ] ⎟ = −kt ⎟ ⎝ 0⎠ Integrated 2nd order rate law: first order half-life: t1 / 2 = 1 1 = + kt [A] [A]0 ln( K ) = − ΔH R ⎛ 1 ⎞ ΔS ⎜ ⎟+ ⎝T ⎠ R [A]0 2k ln 2 k second order half-life: t1 / 2 = 1 k [A ]0 k = A e–Ea/RT ⎛ k ⎞ – Ea ⎛ 1 1⎞ ln ⎜ 2 ⎟ = ⎜T – T ⎟ R⎝2 ⎝ k1 ⎠ 1⎠ ln(k )=ln( Α) − Beer's law: Absorbance = ε·b·c pH = –log[H3O+] pOH = –log[OH-] Kw= KaK b pKw = pH + pOH pKa = –log Ka ⎛ [conjugate base] ⎞ ⎟ [acid] ⎝ ⎠ Henderson-Hasselbalch equation: pH = p Ka + log ⎜ Ea RT THE UNIVERSITY OF MANITOBA April 17 , 2010 FINAL EXAMINATION PAGE NO: 1 of 10 DEPARTMENT & COURSE NO: CHEM 1310 TIME: 3 HOURS EXAMINATION: University I Chemistry: Intro. to Phys. Chem. EXAMINER: CHEM 1310 Committee THIS EXAM CONSISTS OF TWO PARTS : Part A (multiple -choice) and Part B (free -response) Part A of this CHEM 1310 April final examination paper is an objective - type, machine- scored examination. All questions in this paper are of equal value. Part A is worth 30 marks (or 60% of the 50 marks allotted to this final examination) and should require approximately 90- 100 minutes to complete. There are forty (40) questions on Part A of this examination paper. NOTE: THERE ARE 2 COLORED CODED VERSIONS TO PART A. YOU MUST USE THE MATCHING BUBBLE SHEET GIVEN BELOW If your Part A exam is BLUE Use a BLUE colored bubble sheet If your Part A exam is YELLOW Use a RED colored bubble sheet GENERAL INSTRUCTIONS Do not fold, staple, tear, or otherwise mutilate the answer sheet. Indicate your answers with a bold mark on the answer sheet, using a soft lead (graphite) pencil. If you do any erasing, be sure that erasures are complete. Each question has ONE correct answer only. DO NOT MARK MORE THAN ONE ANSWER PER QUESTION. Marks will NOT be deducted for wrong answers. Blank sheets are attached to this examination to be used for rough work. Numerical answers are correct to within ± 2 in the last significant digit VERY IMPORTANT For accurate processing of the answer sheet for this examination, we must have on your answer sheet: 1. your correct student number , and 2. your name Write your student number in the column marked by a colored arrow on the answer sheet and score your student number correctly in the area to the right of this column. NO CELLPHONES, PAGERS, CALCULATORS WITH TEXT, ETC. ARE PERMITTED. STUDENTS FOUND WITH ANY OF THESE PROHIBITED ITEMS WILL HAVE THEIR ANSWER PAPERS CONFISCATED AND WILL RECEIVE A GRADE OF ZERO ON THE EXAMINATION. Submit the ANSWER SHEET for grading. You may keep this question paper. We suggest that you record your answers so that you may compare them against the answer key which will be available on the ANGEL course site immediately after the examination. FINAL EXAM PART A CHEM 1310 University I Chemistry: Intro. to Phys. Chem. Page: 2 of 10 1) The first law of thermodynamics can be given as __________. A) for any spontaneous process, the entropy of the universe increases B) the entropy of a pure crystalline substance at absolute zero is zero C) ΔS = qrev/T at constant temperature D) ΔH°rxn = ∑nΔH°f (products) - ∑m ΔH°f (reactants) E) ΔE = q + w 2) For a process at constant volume, A) ΔE = ΔH. B) ΔH = q. C) q = w D) ΔE = w and q = 0. E) ΔE = q and w = 0. 3) The values of ΔH°f for the three states of benzene are approximately - 22 kcal/mol, - 11 kcal/mol, and 20 kcal/mol. Which is the value for solid benzene? A) -22 kcal/mol B) 20 kcal/mol C) -11 kcal/mol D) 11 kcal/mol E) cannot be determined without additional information 4) A sample of calcium carbonate [CaCO3 (s)] absorbs 45.5 J of heat, uponwhich the temperature of the sample increases from 21.1°C to 28.5°C. If the specific heat of calcium carbonate is 0.82 J g - 1 °C- 1 , what is the mass (in grams) of the sample? A) 5.0 B) 3.7 C) 7.5 D) 410 E) 5.0 x 10 3 5) The magnitude of the heats of vaporization and fusion of a substance reflect the A) strength of the intermolecular forces of the substance. B) strength of the covalent bonds between atoms in each molecule of the substance. C) density of the substance. D) the molar mass of the substance. E) None of the above are true. 6) A 4.976 g sample of potassium sulfate is added to a coffee cup calorimeter containing 122.6 g of distilled water at 22.43°C. After the sample had dissolved, the temperature was 21.11 °C. What is the molar enthalpy of dissolution of potassium sulfate, i.e. K 2 SO4 (s) → 2 K + (aq) + SO 4 2 - (aq) Assume that the specific heat of the salt solution is 4.18 J g - 1 °C- 1 . A) 18.4 kJ/mol B) -18.4 kJ/mol C) 24.6 kJ/mol D) -24.6 kJ/mol E) 136 kJ/mol ΔH = ? FINAL EXAM PART A CHEM 1310 University I Chemistry: Intro. to Phys. Chem. Page: 3 of 10 7) Given the following reactions and their enthalpy changes, What is the enthalpy change for the reaction A) +26 kJ B) -26 kJ C) +478 kJ D) -478 kJ E) cannot be determined without additional information 8) The reaction that occurs in a Breathalyzer, a device used to determine the alcohol level in a personʹs bloodstream, is given below. If the rate of appearance of Cr 2 (SO4 )3 is 1.64 mol/min at a particular moment, what is the rate of disappearance of C 2 H6 O at that moment? 2 K2 Cr2 O7 + 8 H2 SO4 + 3 C2 H6 O → 2 Cr 2 (SO4 )3 + 2 K 2 SO4 + 11 H 2 O A) 2.46 mol/min B) 9.84 mol/min C) 1.09 mol/min D) 4.92 mol/min E) 0.547 mol/min 9) The decomposition reaction of NO2 is important in atmospheric chemistry. The reaction 2NO 2 (g) → 2NO(g) + O 2 (g) is second order with respect to NO 2 . How can the rate constant be determined? A) A plot of ln[NO2 ] versus time will be linear with a slope of -k. B) A plot of [NO2] versus time will be linear with a slope of - k. C) A plot of 1/[NO2] versus time will be linear with a slope of - k. D) A plot of ln[NO2 ] versus temperature will be linear with a slope of -k. E) A plot of 1/[NO2] versus time will be linear with a slope of k. 10) The reaction for the decomposition of dinitrogen monoxide gas to form oxygen radicals is: N2 O( g ) → N2 (g ) + O(g ). If the rate constant is 3.04 × 10- 2 s- 1 and the frequency factor is 8.00 × 1011 s- 1 , what is the activation energy for the first- order reaction at 700°C? A) 0.262 kJ/mol B) 250 kJ/mol C) 38.2 kJ/mol D) 180 kJ/mol E) 24.3 kJ/mol FINAL EXAM PART A CHEM 1310 University I Chemistry: Intro. to Phys. Chem. Page: 4 of 10 11) The rate constant, k, for a reaction is equal to 4.2 × 10-4 s- 1. What is the half-life for the reaction? A) 1.2 × 103 s B) 1.7 × 103 s C) 2.9 × 10- 4 s D) 2.4 × 103 s E) cannot be determined without additional information 12) The following reaction was studied. NH3 (g) + BF 3 (g) → F 3 BNH 3 (s). Experiment [BF3 ] [NH3 ](M) 1 2 3 4 5 0.250 0.250 0.200 0.350 0.175 0.250 0.125 0.100 0.100 0.100 Initial Rate (M/s) 0.2130 0.1065 0.0682 0.1193 0.0596 Based on the data in the preceding table, what is the reaction order with respect to BF 3 ? A) Zero order B) First order C) 3/2 order D) Second order E) Cannot be determined 13) A homogeneous catalyst is added to an exothermic reaction. When this occurs, which one of the following is not affected? A) rate of the reverse reaction B) rate of heat given off by the reaction C) the equilibrium constant D) the types of reaction intermediates generated E) the activation energy for the forward reaction 14) Which statement is true for a reaction with Kc equal to 2.43 × 10- 12? A) Increasing the temperature will not change the value of Kc. B) The reaction proceeds hardly at all towards completion. C) The reaction proceeds nearly all the way to completion. D) There are appreciable concentrations of both reactants and products. E) The reaction is always endothermic. FINAL EXAM PART A CHEM 1310 University I Chemistry: Intro. to Phys. Chem. Page: 5 of 10 15) Oxalic acid can donate two protons to water in successive reactions: (1) H 2 C2 O4 (aq) + H2 O( l) ⇌ H3 O+ (aq) + HC2 O4 - (aq) (2) HC2 O4 - (aq) + H2 O( l) ⇌ H3 O+ (aq) + C 2 O4 2 - (aq) If Kc1 = 5.9 × 10- 2 and Kc2 = 6.4 × 10- 5 at 25°C, what is the value of Kc for reaction (3)? (3) H 2 C2 O4 (aq) + 2 H2 O( l) ⇌ 2 H3 O+ (aq) + C 2 O4 2 - (aq) A) 1.1 × 10- 3 B) 6.4 × 10- 5 C) 3.8 × 10- 6 D) 5.9 × 10- 2 16) Consider a reaction that occurs by the following mechanism: A + BC → AC + B AC + D → A + CD The potential energy profile for this reaction is shown below. Transition states occur at which reaction stages? A) reaction stage 3 B) reaction stages 1 and 5 C) reaction stages 2, 3, and 4 D) reaction stages 2 and 4 E) reaction stage 2 only 17) Nickel metal can be prepared by the reduction of nickel oxide: NiO(s) + CO(g ) ⇌ CO2 (g ) + Ni(s) At 936 K, Kp = 4.54 × 103 and at 1125 K, Kp = 1.58 × 103 . Which statement is true? A) The reaction is exothermic. B) The reaction is endothermic. C) The activation energy decreases with increasing temperature. D) The activation energy increases with increasing temperature. E) Both at 936 K and 1125 K, ΔG° > 0 E) 9.2 × 102 FINAL EXAM PART A CHEM 1310 University I Chemistry: Intro. to Phys. Chem. Page: 6 of 10 18) The isomerization of cis- 2- butene to trans-2 -butene (below) has an equilibrium constant of 1.50 at 580 K. If 1.40 mol of cis- 2 - butene is placed in a 1.0 liter flask, what is the equilibrium concentration of trans- 2 - butene? A) 0.60 M B) 0.56 M C) 0.84 M D) 1.79 M E) 2.1 M 19) The esterification of acetic acid and ethanol is given by the reaction below: C2 H5 OH(aq) + CH3 COOH(aq) ⇌ CH3 COOC2 H5 (aq) + H2 O( l) When 1.00 mol of ethanol was mixed with 2.00 mol of acid in a 1.00 L flask, 0.86 mol of ester was formed at room temperature. What is the value of the equilibrium constant, Kc? A) 0.43 B) 4.6 C) 5.4 D) 2.3 E) 0.16 20) Which one of the following processes produces a decrease in the entropy of the system? A) freezing water to form ice B) mixing of two gases into one container C) melting ice to form water D) boiling water to form steam E) dissolution of solid KCl in water 21) For bromine, ΔH°vap = 30.91 kJ/mol and ΔS°vap = 93.23 JK - 1mol- 1 at 25°C. What is the normal boiling point for bromine? A) 100°C B) 25°C C) 58°C D) 332°C 22) For the conversion of ice to water at 25°C and 1 atm, A) ΔG is positive and ΔH is negative. B) ΔG is negative and ΔH is negative. C) ΔG is negative and ΔH is positive. D) ΔG is positive and ΔH is positive. E) cannot be determined without additional information 23) Which of the listed reactions would couple with the following reaction to produce silver? Ag2 O(s) → 2 Ag(s) + 1/2 O2 (g) A) C + 1/2 O2 → CO B) N + O 2 → NO2 C) N + 1/2 O2 → NO D) Ag(s) + 1/2 Br2 → AgBr(s) E) C + 2 S → CS2 (l) ΔG° = 11.2 kJ/mol ΔG° = - 137.2 kJ/mol ΔG° = 51.3 kJ/mol ΔG° = 149.3 kJ/mol ΔG° = 96.9 kJ/mol △G° = 65.3 kJ/mol E) 124°C FINAL EXAM PART A CHEM 1310 University I Chemistry: Intro. to Phys. Chem. Page: 7 of 10 24) Which of the following reactions will have the largest equilibrium constant (K) at 298 K? ΔG° = + 326 kJ A) 3 O2(g) → 2 O3 (g) ΔG° = + 131.1 kJ B) CaCO3 (s) → CaO(s) + CO2 (g) ΔG° = - 180.8 kJ C) 2 Hg(g) + O2 (g) → 2 HgO(s) ΔG° = - 28.0 kJ D) Fe 2O3 (s) + 3 CO(g) → 2 Fe(s) + 3 CO 2(g) E) It is not possible to determine without more information. 25) Determine the equilibrium constant for the following reaction at 549 K. CH2 O(g) + 2 H2 (g) → CH4 (g) + H2 O(g) B) 9.35 x 10- 10 A) 1.07 x 109 ΔH° = - 94.9 kJ; ΔS°= - 224.2 J/K C) 1.94 x 10- 12 D) 481 E) 2.08 x 10- 3 26) Complete the following equation. List the conjugate acid base pairs, so that for each pair, given in brackets, the base is listed first. HCl + NH3 ⇔ (NH3 , NH2 - ) (HCl, H2 Cl) A) H2 Cl+ + NH2 - (NH3 , NH4 + ) (Cl- , HCl) (NH3 , Cl - ) (NH 4 + , HCl) B) Cl- + NH4 + C) Cl- + NH4 + D) Cl- + NH4 + E) H2 + Cl- + NH2- (NH3 , HCl) (Cl- , NH4 + ) (NH3 , NH2 - ) (Cl- , HCl) 27) Using the data in the table, which of the conjugate bases below is the weakest base? Acid Ka 1.8 × 10- 5 HCHO2 1.8 × 10- 4 HClO 3.0 × 10- 8 HOAc HF 6.8 × 10- 4 A) OAcB) ClOC) FD) CHO2E) OAc- and CHO228) A saturated aqueous solution of calcium hydroxide has a pH of 12.25 at 25 °C. What is the [Ca 2+ ] of such a solution? A) 5.6 × 10- 13 B) 0.018 C) 8.9 × 10- 3 D) 2.3 × 10- 5 E) 0.035 29) The Ka of hypochlorous acid (HClO) is 3.0 × 10-8 at 25.0°C. What is the % ionization of hypochlorous acid in a 0.015 M aqueous solution of HClO at 25.0°C? A) 14 % B) 2.1 × 10- 5 % C) 1.4 × 10- 3 % D) 0.14 % E) 4.5 × 10- 8 % FINAL EXAM PART A CHEM 1310 University I Chemistry: Intro. to Phys. Chem. Page: 8 of 10 30) What is the second stepwise equilibrium constant expression for phosphoric acid H 3PO4 ? A) Ka2 = ([H3O+ ]3[PO4 3- ])/([H3PO4 ]) B) Ka2 = ([H3O+ ]2[HPO42 -])/([H3 PO4]) C) Ka2 = ([H3O+ ][HPO42 -])/([H2 PO4- ]) D) Ka2 = ([H3O+ ][H 2PO4 -])/([H3 PO4]) E) Ka2 = ([H3O+ ][PO4 -])/([HPO4 2- ]) 31) Which one of the following is not considered to be a Lewis base? A) OHB) ClC) H2 O D) NH3 E) NH4+ 32) Arrange the following 0.10 M aqueous solutions in order of increasing pH: NaOH, HBr, NaCH 3 CO 2, KBr, NH4 Br. A) HBr, NH4Br, KBr, NaCH3 CO 2, NaOH B) NaOH, NaCH 3 CO 2, KBr, NH4Br, HBr C) NaOH, NaCH 3 CO 2, NH4 Br, KBr, HBr D) HBr, KBr, NH4 Br, NaCH3 CO 2, NaOH E) HBr, KBr, NH4 Br, NaCH3 CO 2, NaOH 33) The following plot shows a titration curve, representing the titration of 50.00 mL of 0.100 M acid with 0.100 M NaOH. What is the Ka of the acid? A) 3.0 B) 7.9 x 10 - 3 C) 4.4 D) 1.6 x 10 - 5 E) 1.0 x 10 - 9 FINAL EXAM PART A CHEM 1310 University I Chemistry: Intro. to Phys. Chem. Page: 9 34) Which of the following combinations of chemicals could be used to make a buffer solution? A) HCl/NaOH B) NaOH/NH3 C) NH4NO3/NH3 D) NH4NO3/H3PO4 E) HCl/H3 PO4 The following plot shows a titration curve for the titration of 1.00 L of 1.00 M diprotic acid H 2 A with NaOH. 35) Which point a-d represents the HA -/A2 - buffer region? A) region a B) point b C) region c D) point d E) There is no buffer region 36) Which one of the following observations on a synthesized sample of acetylsalicylic acid, C 9H8O4 , is an indication that the sample is NOT PURE? A) The sample melts at 133—135˚C (literature m.p. = 135˚C) B) A purple color is observed when iron(III) chloride, FeCl 3 , is added to the sample. C) The molar mass of the sample, as determined by the titration, is 179±1 g mol -1 D) The crystals of the sample are very fine rather than the expected large flakes. E) The crystals of the sample do not dissolve readily in water. of 10 FINAL EXAM PART A CHEM 1310 University I Chemistry: Intro. to Phys. Chem. Page: 10 of 10 37) A saturated solution of mercury(II) bromide has a bromide concentration of 6.38 × 10-7 M. What is the solubility product, Ksp, of mercury(II) bromide? A) 1.3 × 10- 19 B) 4.1 × 10- 13 C) 6.2 × 10- 15 D) 3.2 × 10- 20 E) 2.6 × 10- 19 38) The solubility product constant, Ksp, of calcium hydroxide can be estimated after a quantitative analysis (titration) to find either the calcium ion concentration or the hydroxide ion concentration of a saturated solution of pure calcium hydroxide. If a student found the calcium ion concentration to be 0.0180 mol L - 1 , which one of the following is correct? A) The EDTA titration of the hydroxide ion should indicate [OH - ] = 0.0180 mol L-1 . B) The EDTA titration of the hydroxide ion should indicate [OH - ] = 0.0360 mol L-1 . C) The value for Ksp is calculated as Ksp = 3.2 x 10-4 D) The value for Ksp is calculated as Ksp = 2.3 x 10-5 E) The value for Ksp is calculated as Ksp = 5.8 x 10-6 39) In CHEM 1310 laboratory, you studied the kinetics of the reaction of iodide ion with persulfate ion, S 2O8 2— , represented by the chemical equation: 2 I- (aq) + S2 O8 2 - (aq) → I 2 (aq) + 2 SO4 2 - (aq) To measure the time required for a specific amount of diiodine to be produced, you added sodium thiosulfate, Na2 S2 O3 , and starch solution and observed the time required for the appearance of a blue - black color. Which one of the following changes will have the LEAST EFFECT on the time required for the blue - black color to appear? A) increasing the concentration of persulfate ion B) increasing the concentration of iodide ion. C) increasing the concentration of sodium thiosulfate D) increasing the concentration of the starch solution E) increasing the temperature of the reactants 40) In the preparation of acetylsalicylic acid (molar mass, 180 g mol - 1), 2.00 g of salicylic acid (molar mass, 138 g mol- 1 ) were reacted with excess acetic anhydride. If 1.00 g of purified acetylsalicylic acid was produced: A) The percent yield is 50.0%. B) The percent yield is 38.3%. C) 1.45 x 10—2 mol of acetylsalicylic acid are produced. D) The limiting reactant is acetic anhydride because it is in excess. E) None of the alternatives a) to d) is a good answer. Answer Key Testname: 2010_PARTA_FINAL_RED_VERSION E 2) E 3) A 4) C 5) A 6) C 7) A 8) A 9) E 10) B 11) B 12) B 13) C 14) B 15) C 16) D 17) A 18) C 19) C 20) A 21) C 22) C 23) A 24) C 25) E 26) B 27) C 28) C 29) D 30) C 31) E 32) A 33) D 34) C 35) C 36) B 37) A 38) D 39) D 40) B 1) ...
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