Ex2Key0 - W K4) ammm WM“ CHM 2046 EXAM 2, FORM CODE A...

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Unformatted text preview: W K4) ammm WM“ CHM 2046 EXAM 2, FORM CODE A 0613. 15, 2008 Please bubble in A as the test Form Code at the top right of your answer sheet. Failure to do this will result in a penalty of 10 points. 1. In the eqn for the chemical rxn at 25 °C which corresponds to AH? for neodymium acety~ lacetonate, Nd[CH(COCl—I3)2]3(s), the total number of moles of solid-phase reactants is (1) 12 6 (3) 20 (4) 8 (5) 17. Of the following solns at 25 °C, 0.8003(5) should be least stable in W 1 M H4NCI M H4NF >54 0.5 M (HiNhSO4 >1 0.5 M H4NH003 1M Na2804. EEK ' 3. For: H200) —> 1120(3) at —10 °C, it is true that this process is (1) at EQ (2) exo 85 nonspont (3) endo 35 spont xo 38 spont (5) endo 85 nonspont. 4. For the EQ: CaF2(s) + HOCOg—(aq) + H3N(aq) ~T—‘ CaCOa(s) + H4N+(aq) + 2 F‘(aq), K is closest to .2x10-4 (2) 7.6x10“5 (8) 8.8 (4) 0.047 (5) 1.3x102. 5. If 25.0 mL of 0.80 M H3N is mixed with 40.0 mL of 0.25 M H4NCI and then treated with 5.0 X 10‘3 mols HCl(g), the pH of the resulting soln will be closest to (1) 2.35 (2) 5.60 (3) 7.00 (4) 10.50 @25 . 6. For the hypothetical semi-soluble salt MX3(8), in the absence of hydrolysis, it is true that [X‘] = (1) 3(8. new (2) (K. /81)”4 (a) ' (K. new (4) (Ks/20W (5)3(8.§/81)1I4. p C} p 7. The following In which is most exothermic is (1) 1120(8) —* H200) I“12(8) + 1/2 02(8) —> H200) (3) 112(8) + 1/2 02(8) —+ I1120(8) (4 2(8) + 1/3 03(8) —> H200) (5) H208) ‘1" 1/3 03(8) —‘+ Hzoigl- 8. If, for an aqueous soln of (HO)2802 (H2804), it is found that pH : 1.92, then [H30+] :- (1) 2.0 Mi (2) M, .5 Mi (4) 2.5 Mi (5) 1.3 M,. f the following saturated Cacog soln systems, carbonate ion hydrolysis occurs to the small- est extent for 03003 in 3 M H3N 2) aCO3 in 0.01 M KOH CaC03 in aqueous buffer at pH 11.0 3.003 0.01 M H4NNO3 ‘5') (381003 in pure water. E E . 10. An aqueous, equimolar mix of the following listed B / L conjugate acid-base pairs giving a 50121 closest to neutral is (1) HAc/Ac— @ZS/HS' (3) HCN/NC‘ (4) HF/F‘ (5) HOCl/CIO'. 11. For: H200) AH; = —285.8 kJ. For: N2(g) + 2 H200) —> N2H4(1) + 02(8). AH: = 622.3 M For: N2(g) + 4 H200) —+ N2H4(l) + 2 H2020), AB? = 818 kJ - Based on these data, AH];J for the decomposition of H202(l) into its component elements is closest to (1) —220 M (2) —197 kJ (3) 508 Id (4) 305 id @8 k3 . 12. The following largest-extent B/ L A/ B rxn at 25 0C, is I (1) 4 +(aQ) + HO-la‘ifl —‘> H2011) + Hawaii) H30+(aq) + 0032'— (aq) —> + HOCOQ‘(aq) _ F(aq) + HS’ -—*+ H23(3CI) + F_(aCl) Uses—(an) + 801an —e H200) + SOB—(ac!) H30+(aq) + en(aq) ——> Hen+(aq) 4— H200). «my atazFog we 13. Ksp for Ag20(s) corresponds to (1) [As+12102'l (2) [490210212 @I‘lsflwio‘l2 (4) [As+l[02"l[H0'l (5) [AsWHO‘lZ- The following conversion which cannot be readily achieved in one step is I." ‘ ‘ a003(s) into CaSOi-2H20(s) (2 CaCOa(s) into CaF2(s) 7: a(OH)2(s) into Ca003(s) g20(s) into AgCl(s) aF2(s) into Ca(OH)2(s) . 15. If, for a buffered, saturated, aqueous soln of CaCog, it is found that [HOCO‘] = 2[“H2003”], then it is also true that (l) [Ca2+] = (“H.20qu + [0032—] 2) 2[“H2003n] = [039+] (3) 4[0032‘] = [H0002_] (4) [0032‘] = 2[HOCOZ_] a2+l = 3[HOCOg‘] . For 1 M HCl the correct material-balance equation for all hydrogen-containing species is I 0130+] M5 = [H20] + [H30+] (3) 1 x 10-14 = [H3o+][Ho-] _ " = [0130+] + [H2O] + [Ho-1 (5) 55 2 [H20]. dicator HMB is yellow at pH 0.5 or less, green at pH 1.5, and blue at pH 2.5. So, if 350 mL a" 0.03 M HX is treated with a drop of this indicator giving a distinct green color, it follows that as B / L acids (1) HX is somewhat stronger $818413 is much stronger @X is much stronger H (4) HMB is somewhat stronger X & HMB are ~same strength. EEK L 18. 1.0 M H4NHSO4 the correct charge-balance eqn for all species is 2) 4N+] + [H30+] = + 2(8042_] + [HO—l 2[H4N+] + [H30+] = [HOSO3_] + [3042—] (3) 2[H4N+] + [1430+] : [HOSO3‘] + 2[so.,2-] + [110‘] (4) [H4N'l’] = [1108031 + [5042—] (5) [H4N+] = 2[SO42r]. The correct eqn for the EQ established when Ag20(s) is saturated in 1 M H4NN03 is + H4N+ + \_—\ 2 + (2) Agzoei + 2 HaNlaQ) re As(NHa)2+(aq) + H200) (3) 4020(8) + 2 H4N+lacfl + 2 HaNlaQ) FA 2 AglNH3)2+(aCI) + 2 H200) Ag20(s) + 2 H4N+(aq) # 2 Ag(NH3)2+(aq) + 1120(1) g20(s) + 2 H4N+(aq) \——‘ Ag(NH3)2+(aq) + Ag+(aq) + H20(l) . 20. For: Ag(NH3)2+(aq) + Cl#(aq) ;‘ AgCl(s) + 2 H3N(aq), K is 345. Therefore, if this EQ is established by mixing 500 mL of 1.0 M NaCl with 500 IIlL of a soln containing [H3N] = 6.0 and [Ag(NH3)2]+(aq) = 1.0, the amount of AgCl whi will result at EQ will be closest to (1) 0.22 mols (2) 0.55 mols (3) 0.81 mols 1 mols (5) 0.094 mols. @The solubility of Cami-ggin 0.10 M NaOH is about the same as its solubility in .83 M 03.012 _ 0.022 M 00012 12(034 M (33.012 (4) 0.65 M CaClz 1.2 M CaClz. ' 22. Given that saturated, aqueous Aggs soln has a pH of 7.0, each of the following statements is true except (1) Aggs is very slightly soluble (2) calc of soln pH involves K313, Kb(HS‘), 36 Kw (3) Aggs cannot be readily converted to AggCJOg (4) Aggs is likely not readily dissolved by 1 M HON02 @hydrolysis of AggS does not occur . @Rating 0.034 mols Ag2003(s) with 400.0 mL of 0.20 M NaCl will producelan amount of s) closest to GmeniMj) 0.034 mols @068 mols (3) 0.13 mols 26019:;0013 M044 mols. - If a soln is prepared by mixing 45 mL of 1.2 M H4NCl with 60.0 mL of 0.60 M H3N, the amount of 2.0 M H3N which must be added to double [HO‘] is closest to flu mL @18 mL 3,31 24'mL VQ40 mL We mL. \ Gwej‘yiwj ...
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Ex2Key0 - W K4) ammm WM“ CHM 2046 EXAM 2, FORM CODE A...

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