samplefinal_krylov06_key

Samplefinal_krylov06 - 1(14 pts(a(8 pts For each of the following insoluble ionic compounds state whether the solubility will increase decrease or

Info iconThis preview shows pages 1–10. Sign up to view the full content.

View Full Document Right Arrow Icon
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 2
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 4
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 6
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 8
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 10
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: 1. (14 pts) (a) (8 pts) For each of the following insoluble ionic compounds, state whether the solubility will increase, decrease, or remain unchanged as a solution at pH 7 is made acidic. Explain your answer. (i) PbC12 Psalm 5 of“ cut“ pb1+) (1Q,— O/VQ, %% C/OMJMQOAL Gad ‘Lak(erAfi$UU/flb) M VOW be; will swim) goldfiaaléb % bQQZ wlil mi 33:2 W lb?“- (ii) FeS R303.) :2 P82— 31‘ 327% M10 g? HEW—Obi“ (S ~§+VUL153CDKJ_J3&§&) QM + at 3 H ‘ _ Lace/Qua ‘Q’f: C211? 2) mm .7» figl—ABTDCOEQL; (pi/(1‘ —? W :3 h "7 M Wk —? F'iodL/b ==>£31‘—J l, :3 48+ WM$M6K¥13MS,SDlUlO\ (b) (6 pts) The solubility of both salts increases with temperature. It means that: M (i) AHw1> 0 and A850] >0 (ii) AH”, > 0 and A850] < 0 (iii) AHSD1< 0 and AS“,l > O ‘ (iv) AH501< O and A850] < 0 (v) No conclusion about AHSUI can be made, ASH,i > 0 (vi) No conc uSIOn :1 out 501 can e ma e, Sm] <0 (vii) AH“ > 0 , no conclusion about A850! can be made (viii) AHSol < 0 , no conclusion about A5501 can be made AG: varas AC mm W Mpg/Alva (vii/K “7:5 mm lama as»; Mm Seuss; (M \M mm W Miaer Aid is V’QRMMJV kw Tx / 2. (16 pts) Consider tetrahedral complex [CoC12(en)]. (a) Does this compound exhibit geometrical or optical isomerism? Circle the correct answer: (i) The complex can exhibit both geometrical and optical isomerism. (ii) The complex can exhibit geometrical isomerism only. (iii) The complex can exhibit optical isomerism only. (iv) The complex does not exhibit any isomer1sm. ~~ 0L / all Squwtflwfliw/poxfiifl_ CK (b) If one Cl' is replaced by Br‘, what kind of isomerism, if any, are possible in the resulting compound? (i) The complex can exhibit both geometrical and optical isomerism. (ii) The complex can exhibit geometrical isomerism only. (iii) The complex can exhibit optical isomerism only. (iv) The conTplé'fdoes not exhibit any isomerism. Br l /oo 62 pa (c) Determine the oxidation state of Co. of“ ((1) Do you expect the conductivity of water solution of this complex to be higher or lower than that of [Co(en)2]C12? Explain. Couwvb 0g [Cote/MBA CO; is low) (M {if OQZ>socLW (MA Wm “airbus. EQOC/QQ (M224 Mt 0t$gfidam§ molt)er 3. (9 pts) Write balanced nuclear equations and identify missing particles for the following: (a) Electron capture by 82Sr 571 O x?" :9 1- “in i r 4' ‘« r 3 57 ~l “kw/r '- 32. Q a firm (b) Formation of 206T1 through alpha particle emission E 9A0 ‘ N 911 Cl Ki}: 8?) PD‘I + 9» M 4. (18 pts) Can 222Rn and 220Rn decay by alpha particle emission? Hint: Write balanced nuclear equations for these two processes and calculate the changes in mass that would result. The masses of 222Rn and 220Rn atoms are 222.01757 and 220.01140 u, res ectively. Those of 218P0 and 216Po are 218.0089 and 21600192 u, respectively. m ( ‘1 m = A 001g 0315 0 LL 1 ' 19‘3— R “71 1? Po + ‘4 \xle, 4A m -. mama +Ll.001t;0’>1§0~ ZILZDWS} = m K 8" 5L 2 ‘ OOOQO? u, RR fi 87% Pb + Ann: MQ.OO\G‘1*U‘%L : _0\00é8§>w Rx W W AW<OWWM® c037,? — 110‘ 0‘”ch 5. (18 pts) A chemist needs to do an experiment using 1311 (half life = 8.041 days). She needs 25.0 micrograms of the nuclide. What mass of Na13 11 does she have to buy, if it takes 48 hours for the vendor to deliver of the compound? The atomic mass of 1311 is 131.0. ,4. ' 0‘1‘139? i: N 19,3372. 51> Nb : N° 9;“; ":1 [QED/“Cd a l 1 *- ,__. -N0 0; Mir/tad : 322? Ma i%\ :0 @iVW‘ Na woiew- amass Hm I o‘M mwwfwwxz wit/1%“: 017} ml 12.03% Iwcfl Z V matqu ago}; 4 gagzwa :: EHFA'L/ug 6. (25 points) (a) (15 pts) Calculate the pH of a 0.08 M NaCN solution. (Ka(HCN) = 6.2x10‘10) cmaq) + atom 2 RUIN) * 0mm [‘61 £1 e W 7— _..———' Km ” 50MB €9,245” YL — a .— ‘(z‘l K'gflog 3(.l°‘10:—E0l;3 .__..- -l‘Bxlo Ctr? Ho \0 . 0‘0% ’Y 19$wa\\> \(44093 3 .9 ~ 0 my 1 Kw‘ as PH 2 tn + @033“ “0 -1_:__ (b) (4 pts) A buffer is made by dissolving NaCN and HCN in water. Write equations that show how this buffer reacts with added HF and OH'. '6 w { ~ (a ) (M51 Mex-Liv“) CNYQQ) + H10 (6) e H “‘0 + OH ‘1 aoiollQom c4 H+ “*4: elk/‘4, H0” QNQA. (c) (6 pts) Which of the following solutions has the best buffer capacity. Ex lain our answer. low M\ei*ano( ivo quiiw‘oh oi g4“! Q'Jatc‘d‘ (i) 2.0MHCN and 0.5 MNaCN [I la)» m‘teictwi‘ Lo #4 addition 0,1 Ma y 40, Ojibwa] dufiy #4? 0001004104100 0; M44352“ 2!; conjugak 5?)“ W4 m lea equal, (i) 0.01 M HCN and 0.01 M NaCN El (i) 1.0 M HCN and 1.0 M NaCN 7. (18 points) How many moles of NH4C1 must be added to 1.0 L of 0.10 M of NH3 to form a buffer whose pH is 9.0? [Kb (NH3) = 1.8x10'5]. / a 10"” 40 Rb , \ ': 1‘0 1v?xlo“§ 3.00 pangs-k \o%[A/H3]~ 126'} [W‘f] \531VHQ'1: g.g\Sr*S-Oo+\o°3$kmfl : b.1‘3 4’ [050.12. 0.35;]?— -O.7S -W - 1. D 4: RM} \1O_q: \O (4 )EUHA‘D W EL)“: ,1 Ni M0,?) *0" 8. (22 points) The reaction: 502(g)+1/202(g) <¢ S03(g) is carried out at 1.0 atm pressure and has AH° = -98.9 kJ/mole and AS° = -94.0 J/K. (a) At what temperature would equilibrium be achieved, assuming that AH° and AS° do not vary significantly with temperature? 9+ Qflm‘liht‘ium A610 : tut/me" T :; AHU ,— C{OO M (O 0 / .— Ag 9% 33k (b) What would happen to the reaction yield as the temperature is decreased? Justify your answer. I when T dwaw( A (r \ngpMAe/s “mm ( qua mama will log wimv SFOthmeoM'- ' Luau or lit?- Ehbéo/FT Viki M 74) «esp We worm/w Low A63 Us mm Mgcd'iwz. (c) This reaction has activation energy in the forward direction. What would happen to the reaction Qte as the temperature is decreased? Justify your answer. ten: fie" W” Th mére clawed/8A aA 'l’QMLpQ/Lctiw (433% (d) What can you add to the reaction mixture to make it more efficient? LCCVQWSJF will ‘rOMLL Ea m (Imam fit 9. (15 points) At 25°C, K13: 5.3x105 for the reaction N2(g) +3H2(8) <=> 2NH3(g) A atm of ammonia is put into a vessel of constant volume, some of the ammonia After a pressure Pi P1 /2. Determine what was decomposes. At equilibrium the final pressure of ammonia is Pf = the initial pressure Pi of ammonia in the vessel. 1 o o g '74 3" ~a< SEMA 7Q M“ FefiVflL 9—“ -9: a “3‘ 2%: => My.” 74 M ,t 0) . 6| I vs 10. (20 pts.) The mechanism for the decomposition of NOZCI is k NOBr ‘7‘: NO + Br -1 NOBr + Br k2 5 NO +Br2 (a) By making a steady~state approximation for [Br], express the rate of appearance of Br2 in terms of the concentrations of NOBr and NO. Rafie = {$1 CNOQFTEBFJI ; 3‘ [3g] 7 % AYES “’5,— fi [NOB i 7: OH . 9)- -. Alchemkwmmq; [BY]:- izr {New i3” [N0] «t RMOB‘TX “PM? .. Ma my? 011: WWW 3%. [yo] + {’1 [N0 Br] V’ (b) Under what experimental conditions would the rate show a first order reaction behavior? S we team) 4: fitfvoei‘] m d {Em} ,K “E, ‘. [3+ Orcbx Malawi ab: '3’ H 10 11. (25 pts) A silver-silver concentration cell was set up with 10.0 mL of 0.05 M solution of AgNO3 in each half-cell. The potential of this cell was 0.000 V. After 0.002 moles of sodium thiosulfate Na2$203 was added to one of the half-cells, the cell potential was 0.618 V. Silver ion forms a complex with thiosuulfate: Ag”(aq) + 2 S2 32'(aq) <-> Ag(SZO3)23'(aq). (i) Which of the half cells was the anode? Explain your answer. g: 0A 0.09 60574131 v) y: ' ‘4‘ A" O I“, 7' O > It" . v.3 ,’ «Jo M ‘ l 13%] watch“: Ema»qu . Emu { l . U {XLch M MM “ms w. 2m0xc Age/J3 M’ 143mg #3 (W. 11) alculate the equilibrium constant Kf for complex formation. 0.001 mm MM lo lOWJL: OQMSclmog WAngog We“ % 5: Oth I“ O - 00:93“ @6509 vwg‘jfgm . A 1%}? Coot-Yes ASMQSLGE ;: $351033: ‘05 X M 0. OS 0 9v 0 , WC“ “0* X o. it U 0 05 'X f u 620$“ ODS“ .. £92....1W) : “also \43’ C KL “ X W 0‘0‘1‘005‘ \60' (a 1~Lx§ >< tag; ,0 I 3;??910 ., ‘ a Q)“ ‘N wxww ‘ ...
View Full Document

This note was uploaded on 04/25/2008 for the course CHEM 105BL taught by Professor Warshel during the Spring '07 term at USC.

Page1 / 10

Samplefinal_krylov06 - 1(14 pts(a(8 pts For each of the following insoluble ionic compounds state whether the solubility will increase decrease or

This preview shows document pages 1 - 10. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online