Chemistry 2 Name Homework Exam III Form A Section June 2, 202 email IMPORTANT: On the scantron (answer sheet), you MUST clearly fill your name, your student number, section number, and test form (white cover = test form A; yellow cover = test form B). Use a #2 pencil. There are 25 questions on this exam. Check that you have done all of the problems and filled in the first 25 bubbles on the scantron. The maximum score on this exam is 8 points. Your score will be reported in percent (max 00%). Exam policy Hints Calculators with text-programmable memory are not allowed. Relevant data and formulas, including the periodic table, are attached at the end of this exam. Your grade will be based only on what is on the scantron form. The answer key will be posted on the web after the exam (on the Exam Schedule page). You must turn in your cover sheet with your scantron answer form. As you read the question, underline or circle key words to highlight them for yourself. Avoid errors from "mis-reading" the question. Pay attention to units and magnitudes (decimal places) of numbers obtained from calculations. There is no penalty for guessing.
CHEMISTRY 2 Homework Test 3 June 2, 202 FORM A. If the electronic structure of a solid substance consists of a valence band that is completely filled with electrons and there is a large energy gap (> 400kJ) to the next set of empty orbitals, then this substance will be a(n) A. alloy B. insulator C. conductor D. semiconductor E. superconductor ------------------------------------------------------------------------------------------------------------ 2. Which of the following transition metal complexes is paramagnetic? A. [Zn(NH 3 ) 4] 2+ B. [Ti(H 2 O) 6 ] 4+ C. [Fe(H 2 O) 6 ] 3+ (high spin) D. [Os(NH 3 ) 6 ] 2+ (low spin) E. [Co(NH 3 ) 6 ] 3+ (low spin) 3. Which of the following ions has/have noble-gas electron configurations? A. i B. i and ii C. i and iii D. ii and iv E. i, iii and iv i. Se 2 ii. V 3+ iii. Sc 3+ iv. Cu + ------------------------------------------------------------------------------------------------------------
4. Which one of the following is likely to be the monomer unit of a polymer synthesized by addition polymerization? A. O C CH 2 CH 2 CH 2 CH 2 CH 2 C O HO OH CH 3 B. Cl Si Cl CH 3 C. H H C C CH 3 H O D. CH 3 C OH E. CH 3 CH 2 CH 3 --------------------------------------------------------------------------------------------------------------
------------------------------------------------------------------------------------------------------------ 5. Based on the number of valence d electrons, which of the following is most likely to be colorless? A. VBr 3 B. CrCl 3 C. Mn 2 O 3 D. CuSO 4 E. TiCl 4 ------------------------------------------------------------------------------------------------------------ 6. What is the coordination number and the charge on the metal in the following complex? [Pt(en) 3 ](ClO 4 ) 4 Coordination Charge on Number Metal ion A. 6 +4 B. 3 +2 C. 7 +2 D. 6 0 E. 3 +4 7. This reaction is an example of. A. alpha decay B. beta decay C. positron decay D. electron capture E. gamma emission 4 20 Ca + 4 9 K
------------------------------------------------------------------------------------------------------------ 8. How many Faradays of electricity will be required to deposit mole of V 2 O 5 (s) starting with V 2+ (aq)? (Suggestion: write a balanced half reaction.) A. 2 B. 4 C. 5 D. 6 E. 0 ------------------------------------------------------------------------------------------------------------ 9. The spontaneous lead acid battery (discharge) half reactions are: Cathode: PbO 2 (s) + HSO 4 (aq) + 3 H + (aq) + 2 e PbSO 4 (s) + 2 H 2 O( ) Anode: Pb(s) + HSO 4 (aq) PbSO 4 (s) + H + (aq) + 2 e Choose all of the following statements about the lead acid battery that are true: (E = 2.04 V) I. The battery can be recharged if the PbSO 4 (s) is removed from the electrodes. II. The recharging reaction for the lead acid battery is an auto-oxidation reaction. III. The sulfuric acid concentration decreases as the discharge reaction occurs. A. I B. II C. III D. I and II E. II and III 0. The half-life of 239 Pu is 24,000 years. What fraction of the 239 Pu present in nuclear wastes generated in the year 2000 will be present in the year 3000? A. 0.95 B. 0.92 C..03 D. 0.97 E. 0.90 Go on to the next page
. Which of the following are properly matched with the type of crystal that will form upon solidification?. LiCl ionic 2. Ca metallic 3. SeO 2 network covalent 4. SiO 2 molecular A. and 2 only B. 3 and 4 only C., 3 and 4 D. 2, 3 and 4 E. All are properly matched. 2. Use this energy level diagram to answer this question. Which one of the following has a bond order of 2 and two unpaired electrons? A. NF B. 2 O 2 C. NO D. CN E. CO Go on to the next page
3. The concentration of a reaction was measured as a function of time and the following plot was obtained. If the slope of the plot is 4.5 0 2 M s and the y-intercept is 20 M which one of the following statements is true? A. [A] 0 (the initial concentration of A) is 0.5M. B. The reaction is first order in A. C. The rate constant is 4.5 0 2 M s. D. The half life for this reaction is 5.4 s. E. None of these statements are true. /[A] t(sec) ------------------------------------------------------------------------------------------------------------ 4. The gas phase reaction A(g) + 2B(g) + C(g) D(g) occurs by the following multistep reaction mechanism: () A(g) + B(g) X(g) (fast) (2) X(g) + C(g) Y(g) (slow) (3) Y(g) + B(g) D(g) (fast) What is the rate law for this reaction? A. rate=k[c] B. rate=k[a][b] 2 [C] C. rate=k[a][c] D. rate=k[a][b][c] E. rate=k[a][b] 5. What is the concentration of cadmium ions (Cd 2+ ) in a saturated solution of cadmium carbonate (CdCO 3 )? K sp = 5.20 0 2 A. 5.7 0 7 M B. 5.20 0 2 M C..73 0 4 M D. 4.0 0 6 M E. 2.28 0 6 M ------------------------------------------------------------------------------------------------------------ Go on to the next page
6. Consider that E for 2H 2 O( ) +2e H 2 (g) + 2OH (aq) is 0.83 V, which of the following metals may be produced via electrolysis of an aqueous solution of its nitrate? A. magnesium B. lithium C. nickel D. manganese E. calcium 7. The crystal field splitting energy for a complex is 60kJ/mol. What wavelength of light is absorbed by this complex? A. 750 nm (red light) B. 550 nm (green light) C. 24 nm (ultraviolet light) D. 400 nm (blue light) E. 600 nm (orange light) 8. Which of the following make an acidic solution in water: AlCl 3 NH 4 Cl BaCl 2 KCl? A. AlCl 3 only B. NH 4 Cl only C. AlCl 3, NH 4 Cl, and KCl D. AlCl 3 and BaCl 2 E. AlCl 3 and NH 4 Cl ------------------------------------------------------------------------------------------------------------ Go on to the next page
9. What is [H + ] for a 0.0500 M NaF solution (K a = 7.2 0 4 )? A..2 0 8 M B. 3.6 0 5 M C. 8.3 0 7 M D..3 0 M E. 7.2 0 4 M ------------------------------------------------------------------------------------------------------------ 20. A diprotic acid H 2 Z has acid dissociation constants K a =.0 0 5 and K a2 =.0 0 2. What is the concentration of Z 2 in a 0. M solution of H 2 Z? A..0 0 2 M B..0 0 M C..0 0 3 M D. 0.0 M E. 0.20 M Go on to the next page
2. If the [H 2 CO 3 ] in the blood is.35 0 2 M what must the [HCO 3 ] be in order to maintain a blood ph of 7.40? (pk a for H 2 CO 3 is 6.37. pk a2 is 0.3) A. 0.45 M B..26 0 3 M C..70 0 5 M D. 0.040 M E. 4.30 0 7 M 22. A beaker contains 50 ml of 0.5M NH 3 (aq). It is titrated with 0.5M HNO 3 (aq) at 25 C. K b for NH 3 =.8 0 5. What is the ph at the equivalence point of this titration? A. 4.74 B. 5.9 C. 8.8 D. 9.25 E. 2.9 Go on to the last page
23. What is the standard Gibbs free energy ( G o ) for the following reaction: Cd(s) + I 2 (s) Cd 2+ (aq) + 2I (aq) A..3 0 3 J B. 2. 0 4 J C. 9.4 0 4 J D..8 0 5 J E. 4.2 0 5 J 24. When the following oxidation/reduction reaction is balanced in acid solution, what is the coefficient of H 2 O ( )? NO 2 (aq) + Cr 2 O 2 7 (aq) Cr 3+ (aq) + NO 3 (aq) A. 7 B. 5 C. 0 D. 3 E. 4 25. Arrange the following agents in order of increasing oxidizing power (weakest oxidizing agent to strongest oxidizing agent): H + Fe 2+ H 2 O 2 Cr 3+ Sn A. H + < Fe 2+ < H 2 O 2 < Cr 3+ < Sn B. Sn < H 2 O 2 < H + < Fe 2+ < Cr 3+ C. Cr 3+ < Sn < H 2 O 2 < Fe 2+ < H + D. Cr 3+ < Fe 2+ < H + < H 2 O 2 < Sn E. Sn < Cr 3+ < Fe 2+ < H + < H 2 O 2 END OF HOMEWORK TEST
CHEM 2 Su2 HW Test 3 Scrap Paper
. Standard Electrode Potentials Half-reaction E o /2(V) F 2 (g) + 2e 2F (aq) +2.87 H 2 O 2 (aq) + 2H + (aq) + 2e 2H 2 O(l) +.78 Cl 2 (g) + 2e 2Cl (aq) +.36 O 2 (g) + 4H + (aq) + 4e 2H 2 O(l) +.23 Br 2 (l) + 2e 2Br (aq) +.07 Ag + (aq) + e Ag(s) +0.80 Fe 3+ (aq) + e Fe 2+ (aq) +0.77 O 2 (g) + 2H + (aq) + 2e H 2 O 2 (aq) +0.68 I 2 (s) + 2e 2I (aq) +0.54 Cu 2+ (aq) + 2e Cu(s) +0.34 Sn 4+ (aq) + 2e Sn 2+ (aq) +0.54 Cu 2+ (aq) + e Cu + (aq) +0.53 2H + (aq) + 2e H 2 (g) 0.00 Pb 2+ (aq) + 2e Pb(s) 0.26 Sn 2+ (aq) + 2e Sn(s) 0.36 Co +2 (aq) + 2e Co(s) 0.277 Ni 2+( aq) + 2e Ni(s) 0.28 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) 0.763 2H 2 O(l) + 2e H 2 (g) + 2OH (aq) 0.83 SO 2 4 (aq) + H 2 O(l) + 2e SO 2 3 (aq) + 2OH (aq) 0.93 Mn 2+ (aq) + 2e Mn(s).8 Al 3+ (aq) + 3e Al(s).66 Mg 2+ (aq) + 2e Mg(s) 2.37 Ca 2+ (aq) + 2e Ca(s) 2.76 Li + (aq) + e Li(s) 3.05 3. Equations G = H T S = nfe Data Sheet G o = 2.303 RT log K = RT ln K G = G o + RT ln Q G = G o + 2.303 RT log Q E o = 0.059 log K (at 25 o C) n E = E o 0.059 log Q (at 25 o C) n [ X ] ph = pk a + log [ HX ] K a x K b = K w = [H + ] [OH ] pk w = ph + poh = pk a + pk b K p = K c (RT) Δn log ln N t = N o N t = N o 0.30t t 2 0.693t t 2 = kt 2.303 = kt k = Rate = kn E = mc 2 0.693 t 4. Diagram of d-orbitals for octahedral complexes Energy 2 d x² d y², d z² d xy, d yz, d xz E = hν C = λν 2. Constants R = 8.34 J mol K R = 0.082 L-atm mol K F = 96,500 coulombs mol h = 6.62606876 x 0 34 J-s mass 0 n =.0086649 amu mass p =.0072765 amu g = 6.02 x 0 23 amu amp = coul sec Avogadro s no. = 6.0224 x 0 23 mol c = 2.99792458 x 0 8 m sec J = kg m 2 sec 2 = C-V K w = x 0 4 at 25 C ln k = ln k k 2 E a RT = E a R Ε a k = Ae ( ) RT + ln A ln[a] = ln[a] o kt [A] = [A] o T 2 T + kt 5. Color Wheel, with Wavelength Range email Name
PERIODIC TABLE of the ELEMENTS MAIN GROUPS MAIN GROUPS A 8A 8 H.008 2A 2 3A 3 4A 4 5A 5 6A 6 7A 7 2 He 4.003 3 Li 6.94 4 Be 9.02 TRANSITION METALS 5 B 0.8 6 C 2.0 7 N 4.007 8 O 5.999 9 F 8.998 0 Ne 20.80 Na 22.990 2 Mg 24.305 3B 3 4B 4 5B 5 6B 6 7B 7 8B 8 8B 9 8B 0 B 2B 2 3 Al 26.982 4 Si 28.086 5 P 30.974 6 S 32.066 7 Cl 35.453 8 Ar 39.948 9 K 39.098 20 Ca 40.078 2 Sc 44.956 22 Ti 47.867 23 V 50.942 24 Cr 5.996 25 Mn 54.938 26 Fe 55.845 27 Co 58.933 28 Ni 58.693 29 Cu 63.546 30 Zn 65.39 3 Ga 69.723 32 Ge 72.6 33 As 74.992 34 Se 78.96 35 Br 79.904 36 Kr 83.80 37 Rb 85.468 38 Sr 87.62 39 Y 88.906 40 Zr 9.224 4 Nb 92.906 42 Mo 95.94 43 Tc [98] 44 Ru 0.07 45 Rh 02.90 46 Pd 06.42 47 Ag 07.87 48 Cd 2.4 49 In 4.82 50 Sn 8.7 5 Sb 2.76 52 Te 27.60 53 I 26.90 54 Xe 3.29 55 Cs 32.9 56 Ba 37.33 57 La* 38.9 72 Hf 78.49 73 Ta 80.95 74 W 83.84 75 Re 86.2 76 Os 90.23 77 Ir 92.22 78 Pt 95.08 79 Au 96.97 80 Hg 200.59 8 Tl 204.38 82 Pb 207.2 83 Bi 208.98 84 Po [209] 85 At [20] 86 Rn [222] 87 Fr [223] 88 Ra [226] 89 Ac** [227] 04 Rf [26] 05 Db [262] 06 Sg [266] 07 Bh [264] 08 Hs [265] 09 Mt [268] 0 [269] [272] 2 [277] 4 [285] 6 [289] 8 [293] * LANTHANOIDS 58 Ce 40.2 59 Pr 40.9 60 Nd 44.24 6 Pm [45] 62 Sm 50.36 63 Eu 5.96 64 Gd 57.25 65 Tb 58.92 66 Dy 62.50 67 Ho 64.93 68 Er 67.26 69 Tm 68.93 70 Yb 73.04 7 Lu 74.97 ** ACTINOIDS 90 Th 232.04 9 Pa 23.04 92 U 238.03 93 Np [237] 94 Pu [244] 95 Am [243] 96 Cm [247] 97 Bk [247] 98 Cf [25] 99 Es [252] 00 Fm [257] 0 Md [258] 02 No [259] 03 Lr [262]