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Chem 1/16 Spring 014 First Cmmn Part I (4 pints each) 1. Fr the reactin: BrO aq BrO aq Br aq a. -0.1 M/min b. 0.1 M/min c. 0.06 M/min d. 0.04 M/min e. 0.6 M/min, what is the rate f reactin, if Δ[BrO - ]/Δt = -0.1 M/min? 1 BrO 10.1M rate f reactin 0.04 M / min t min. Suppse fr the abve reactin, under different cnditins, the initial cncentratin f BrO - is 0.51 M. Twentyne secnds later its cncentratin is 0.15 M. What is the average rate f change f Br - cncentratin? a. -0.017 M/s b. 0.017 M/s BrO 0.15 0.51M 0.0171 c. 0.06 M/s t 1s d. 0.011 M/s 1 BrO 1 Br Br BrO e. 0.04 M/s rate f reactin ; 0.0171 0.011Ms t t t t 1. Fr the reactin A(g) + B(g) C(g) + D(g), the fllwing experimental data were btained fr the rate. What is the verall rder f reactin? a. 0 Frm runs 1 and, dubling A at cnstant B, quatruples the rate. b. 1 S the rate f reactin with respect t A is nd rder. Frm runs c..5 d. 1 and, changing B at cnstanta has n effect. S, the rate f e. reactin is 0 rder with respect t B. Over all rder = +0 =. Run [A] (M) [B] (M) Rate (M/min) 1 0.05 0.0. 0.050 0.0 8.8 0.05 0.40. 4. Fr the abve reactin, what is the rate cnstant,? a.,500 M -1 min -1 b. 180 min -1 rate 8.8 M / min rate f reactin A ; 50,500M min c. 180 M - min -1 A 0.05M d. 180 M -1 min -1 e..8x10-4 min -1 1 1 5. Suppse the rate f reactin is secnd rder fr A B + C. What is the apprximate cncentratin f A (in M) after 55 s if [A] = 0.80 M and = 0.05 M -1 s -1 a. 0.1 M b. 0. M 1 1 1 1 1.175 M t 0.05M s 55 s ; A 0.1M c. 0. M A A 0.8M M.175 d. 0.4 M e. 0.6 M 6. Fr a certain reactin at 0ᵒC, when the natural lg f the reactant cncentratin is pltted against the time a straight line is btained whse slpe is -0.0016s -1. The initial reactant cncentratin is 0.80 M. What is the cncentratin after 7.5 min? a. 0. M b. 0.4 M The reactin is first rder. S, ln A ln A t and slpe c. 0. M 0.0016 60s 7.5min 0.94 ln d. 0.7 M A ln 0.8 x x 0.94; A e 0.9M s min 1 e. 0.8 M
Chem 1/16 Spring 014 First Cmmn 7. Suppse the half-life is 9.5 s fr a first rder reactin and the reactant cncentratin is 0.084 M 6 s after the reactin starts. Apprximately hw many secnds after the start f the reactin des it tae fr the reactant cncentratin t decrease t 0.01 M? a. 0 ln ln 1 0.070 s. lna ln A t; b. 5 t1/ 9.5s c. 0 ln A ln A ln 0.084 ln 0.01 d. 40 t 19 s; ttal time = 19+6 = 45s 1 0.70s e. 45 8. An enzyme catalyst lwers the activatin energy fr the decmpsitin f hydrgen perxide frm 7 J/ml t 8 J/ml. Calculate the factr by which the rate f reactin increases at 00 K, assuming that everything else is unchanged. In ther wrds, abut hw many times faster is the reactin? a. 5x10 1 8,000J 8.1J 00K b. 5x10 cat / x Ea / RT ml mlk 1 c. 5x10 4 Ea / RT cat Ae e 7 Rate f reactin Ae ; 4.6x10 E / 7,000 8.1 00 d. 5x10 5 a RT J J K Ae / x ml mlk 1 e e. 5x10 7 9. Ammnia can be prduced by the fllwing reactin: N g H g NH g. Suppse 150 trr f nitrgen are mixed with 00 trr f hydrgen. What is the apprximate pressure f the nitrgen when the ttal pressure 70 trr? a. 110 trr Ng Hg NHg Ptt P P 150 00 450 70 N H PNH x x x x b. 90 trr I 150 00 0 x 40 c. 40 trr C -x -x +x P 150 x 110trr N d. 10 trr E 150-x 00-x x e. 10 trr 10. Cnsider the balanced equatin: A + B C + D. 4.0 ml A are mixed with.0 ml B at an elevated temperature. After.5 ml f A have reacted, hw much B is left? a. 0.9 ml b. 1. ml.5mla mlb x 1.7 ml Bused; 1.7 1.ml Bleft c. 1.5 ml 1 mla d. 1.6 ml e. 1.7 ml 11. What is the equilibrium expressin fr the water-gas shift reactin at 70 C: CO(g) + H O(l) CO (g) + H (g)? a. K eq COH COH O c. K eq COH CO b. K eq COHO CO H
Chem 1/16 Spring 014 First Cmmn 1. Cnsider the reactin: A(g) + B(g) C(g) + D(g). In a.00 L cntainer the reactants and prducts are at equilibrium. There are 0.0 ml A, 0.40 ml B, 1.7 ml C, and 0.50 ml D. What is the equilibrium cnstant, K C? a..5 ml/l 1.7ml 0.5ml b. ml/l C D L L c. 96 ml/l KC ml/ L AB 0.ml 0.4ml d. 96 L L e. 11 1. A 0.0 L reactin cntainer is charged with 0.60 ml f NOBr, which decmpses at a certain temperature accrding t the fllwing reactin: NOBr(g) NO(g) + 0.5Br (g). At equilibrium the brmine cncentratin is 1.0x10 - M. What is the apprximate value f K c (units M 0.5 )? Br 0.01M 0.5 x; x 0.0M 0.6ml a. 0.0 NOBr 0.0M NO x 0.0M 0L b. 1 NOBr 0.0 x 0.01M c. d. NOBr g NO g 0.5Br g e. 5 NOBr 0.5 0.0M0.01M 0.5 I 0.0 0 0 K C 0.M NOBr 0.01M C -x +x +0.5x E 0.0-x x 0.5x 0.5 14. Determine the equilibrium cnstant fr the reactin: Ca(OH) (s) Ca + (aq) + OH - (aq), given 0.40 ml f Ca(OH) is placed in L f water and stirred. At equilibrium, at a certain temperature, 0.018 ml f Ca(OH) disslves. (Assume, the vlume f the slutin is the same as the initial vlume f water.) a. x10-6 M b. 5x10-6 M c. x10-5 M d. >10-4 M e. <10-7 M 0.018ml L Ca 0.009 M ; OH Ca 0.018M 6 Keq Ca OH 0.009M 0.018M.9x10 M 15. The equilibrium cnstant fr the reactin belw is 0.16 M 0.5 at 000 K. Determine Q c fr the cnditins given belw and in which directin the reactin ges t btain equilibrium. 5L cntainer a. Q C = 0.7M 0.5 ; t the left b. Q C = 0.4M 0.5 ; t the left c. Q C = 0.60M 0.5 ; t the left d. Q C = 0.4M 0.5 ; t the right e. Q C = 0.60M 0.5 ; t the right COO 0.5 0.08M0.16M 0.4ml CO 0.08 M, etc.; QC 0.7M 5L CO 0.1M CO g CO g 0.5 O ( g) 0.6 ml 0.4 ml 0.8ml 0.5 0.5 16. Sme C and water vapr react accrding t the fllwing reactin: Cs H Og CO g H g. After equilibrium is btained, which f the fllwing changes will cause the reactin t shift t the right t mae mre prduct t reestablish equilibrium? a. Adding mre slid carbn. Le Chatelier's Principle. In this case the stess is t little pressure b. Adding mre carbn mnxide when the vlume is increased. S, reactin shifts t the right t c. Increasing the vlume f the cntainer increase the pressure. d. Decreasing the vlume f the cntainer e. Adding an inert gas
Chem 1/16 Spring 014 First Cmmn 17. This reactin is exthermic: CH Os O g CO g HOl will increase the equilibrium yield f water. a. Increasing the vlume b. Decreasing the vlume c. Increasing the temperature d. Decreasing the temperature e. Adding mre carbn dixide 6 6 6. Predict which f the fllwing 6 1 6 18. Which f the fllwing cmpunds is sluble in water? a. Hg(OH) b. PbCl c. F O d. FeS e (NH 4 ) PO 4 Le Chatelier's Principle. Thin f what happens with the buncing beads as the average bead energy decreases fr an exthermic prcess--mre mve t the lwer energy state. 19. Calculate the apprximate slubility f cpper (II) idate in 0.80 M cpper (II) nitrate. K sp is 7.4x10-8 M. (Yu shuld nw that the K sp must refer t the cpper idate because all nitrate cmpunds are sluble and strng electrlytes!) a. 0.006 ml/l CuIO Cu aq IO aq b. 0.004 ml/l c. 0.005 ml/l d. 0.007 ml/l e. 0.00ml/L I C E excess -s excess 0.8M +s 0.8+s 0 +s s 8 0.8 7.4 10 Ksp Cu IO s s x 8 1/ 7.4x10 4 is small. S, 1.5 10 / s s x ml L 0.8x4
Chem 1/16 Spring 014 First Cmmn Part II. 1a. ( pts) Add and simplify the fllwing elementary reactins t determine the verall hypthetical reactin. Cl CO COCl 1b. ( pts) What is(are) the intermediate(s)? Cl COCl 1c. (4 pts) What is the rate law fr the fllwing prpsed mechanism? Cl Cl Cl CO COCl COCl Cl COCl Cl 1 f Cl CO COCl r COCl Cl COCl Cl slw step fast; equilibrium fast rate Cl 1 1d. (4 pts) What is the rate law fr the fllwing prpsed mechanism? D nt include intermediates in yur final answer. 1 f Cl Cl fast; equilibrium rate COCl Cl 1r f Cl CO COCl r COCl Cl COCl f Cl CO r COCl COCl Cl CO fast; equilibrium slw f ; Cl Cl Cl C 1 f ; l 1f 1r 1r rate COCl Cl Cl CO Cl CO f f f 1 f = Cl CO = = Cl r CO Cl CO Cl where f 1f f 1f r1r r1r r r r 1r
Chem 1/16 Spring 014 First Cmmn a. (4 pts) A 0.55 M aluminum chlride slutin is prepared. Sdium hydrxide is added t prduce a precipitate. What is the hydrxide in cncentratin when the aluminum in cncentratin is 1x10-10 M? Al OH s Al aq OH aq K x10 M 4 4 sp 4 4 Ksp Al OH 10 x M 4 4 1/ K sp 10 x 10 x 8 ; 1.44 10 10 10 OH OH x M Al 110 x 110 x b. (4 pts) Cnsider the frmatin f hydrgen fluride: H (g) + F (g) HF(g). A 6.5 L nicel reactin cntainer initially cntains 0.4 M H and 0.18 M F. The equilibrium cnstant, K c, is 8 x 10 14. Calculate the mlar cncentratin f HF at equilibrium. Because K is very large the reactin essentially ges t cmpletin. I C E H g F g HF g 0.4M 0.18M 0-0.18M -0.18M +0.6M 0.06M 0 0.6M c. (4 pts) Calculate the mlar cncentratin f F at equilibrium fr the abve reactin and initial cnditins. HF HF 0.6M 15 K ; F.7x10 M 14 H F KH 810 x 0.06
Chem 1/16 Spring 014 First Cmmn