C111PF07T3 - N 1 {V1 574“? ‘9:- Sdr 075-0 fl‘néowé...

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Unformatted text preview: N 1 {V1 574“? ‘9:- Sdr 075-0 fl‘néowé % I Wio‘l SUM: CHEMISTRY 111 30101 39-”? _ THIRDEXAM‘CQ 9°th NOVEMBER 16,200? r ;. k ( . C BUBBLE 1N YOUR NAME AND STUDENT NUMBER ON THE SCANTRON SHEET FOR PROPER l) IDENTIFICATION. THERE IS ONLY ONE BEST ANSWER FOR EACH QUESTION. ' lie “9 m GOOD LUCK *** J \ <5" <0 1. Cons der the lhrde substances belohv. Which of the three has the largest dipole-dipole attraction? A. Cl; B. Br; C. (l) A (2) B @C (4) all are the same (5) none of these have dipole—dipole forces ‘< L . 2. Consider the same three substances as in 1 above. Which of these has the largest London fochoQ-Sgtfi} \x§ \ attraction? ‘3} (1) A (2)} (3) C (4) all are the same (5) none of these have London force 3. Only one of the three substances listed in problem 1 above is a solid at STP. That substance would be ? . (1) A (2) B (3) C (4) more information is needed to answer this question 4. Only one of the three substances listed in problem 1 above is a gas at STP. That substance would be__?_. T (1) A (2) B (3) C (4) more information is needed to answer this question '_‘- f 5. At temperatures higher than Tcritical for a substance X, we might expect that variations in pressure could ‘il :- piréoduce which of the o owmg phases for substance X? “(k-5‘5 Lg ('1‘ .- 1 th and solid hases are ssible above T 't‘cal ‘“ . ony e gas 1) 130 m1 , d ..__._‘;?-.- I \ (2) only the liquid and solid phases are possible abov Tcritical (3) depending on pressure, any phase (5, l or g) © only the gas phase is possible above Tcritical (08‘ (5)\ only the liquid phase is possible above Tcritical The next font questions concern a solution of 32 g of methanol (MW = 32) and 54 g of H20 (MW = 18). 6. What is the mole fraction of methanol in the solution? ‘3 @25 (2)033 (3)0.45 (4)0.6? (5)0.75 '— 7. What is the __ ality of the methanol solution? (1) 10.2 f? 18.5 (3) 23.";' . (4) 27" (5)36 8. The vapor pressure of pure water at 25 °C is 24 mm Hg and that of pure methanol is 120 mm Hg. What is the vapor pressure of this solution of methanol and water at 25°C? (1)16mran (2)26mmHg (3)31 nuan (4)39mn'1Hg @Smmflg 9. What is the mole fraction of methanol in the a n r above the solution? (1) 0.25 (2) 0.33 (3) 0.50 .625 (5) 0.833 The three questions which follow concern the three substances A, B and C with the corresponding phase diagrams shown below. f“ —— PAGE 2 — i1 10. Which of these substances will 11 one hen at a pressure of 760 mm Hg? (1) A only 6? only C Only (4) A & C (5) none of these 7; l 1. (“Which of the three substances has a solid-liquid phase transition line most similar to that of water? ’ (g A only (2) B only (3) C only (4) B & C (5) none of these >/ g( 12. Which of the three substances has ahqtfitLphase that is more dense than the solid phase? (1) A only (2) B only (3) C only (4) B & C (5) none of these “PI-— 13. 1.00 mole of calcium chloride is dissolved in 1000 g of water. What is the freezing point of this solution? [NOTE the freezing point depressio constant of water is l.86°m_1] "(NQIBQC (2) —1.86°C ( 1.86K (4) —3.?2°C @s.53°c “— 14. For the reaction 2N20(g) + N2H4(g) {—> 3N;(g) + 2H;O(g) one starts with 0.100 mole of_l\_lz_0 and 0&0 mole of 1121}; in a 1.00 L container. At equilibrium the container is found to contain 0. __h_‘ it: of N30. How many moles of N2(g) are present at equilibrium? (1) 0.090 (2) 0.040 ) 0 06 (4) 0.020 (5) 0.025 15. ing the information in the problem above, calculate Kc for the given reaction. (1) 4.2 X 10‘1 (2) 0.17 (3) 0 (4) -0.1? (5) 6.3 X 10‘2 16. For the reaction system N204(g) <—D- 2N02(g) at 90°C, Kc = 0.2 2. What is Kp for this reaction system? ._ Q30 (2) 9.1 X 10—3 ' (3) 240 (4) 2.0 (5) 815 1?. At 600 K, Kc for the reaction shown below is 92.6 Ma) + My <—> 2Hltg) If initially 0.10 M I; and 0.10 M H3 are introduced into a eIOSed container at 600 K, what [1-11] will be present at equilibrium? ' iii-{$0.166 M (2) 0.200 M _ (3) 0.0926 M (4) 0.0906 M (5) 0.181 M ' v’. r. ‘ _. i , 13. Kc for the gas phase reaction 2802 -l- l0; <-—> 2:03 is 0.24. Samples of all three gases are placed in a closed container such that [$02] = 0.10M , [0;] = 0.050M and [$03] = 0.10M. Which of the following is true of this gas mixture? (1) It is at equilibrium K ; O _ "A (2) It is not at equilibrium but there is not enough information to tell how [803] will change C «2 ( This is a trick question with no possible answer (QC: ( O ‘0 (4) t is not at equilibrium & the [$03] will increase until equilibrium is reached ‘ 9 _ 1 @t is not at equilibrium & the [$03] will decrease until equilibrium is reached (0 (O ) _ THE NEXT 4 QUESTIONS REFER TO THE EXOTHERMIC EQUILIBRIUM REACTION SYSTEM IN A (QC: :2 CLOSED CONTAINER: 2N0(g) + 2c0(g) <—> N2(g) + 2C02(g) i m (a) . - I (F I I 19. _What would be the effect on this equililarium if the temperature were lowered? 52C) > ’ (l)>shift right (2) shift left (3) no change (4) more information is needed /£-- > ' L C l \ w 20. What would be the effect on this equilibrium if the volume of the container were reduced? C... V _ 1.1 (Li (1) shift right shift left (3) no change (4) more information is needed 3.2% I l 21. What would be the effect on this equilibrium if more Nz(g) were added to the container? “T n “(W (1) shift right shifl left (3) no change (4) more information is needed \ g G 1‘» *PAGE 3 — Le Chatilier’s Principle ( the Law of Conservation of Mass 22$ three previous problems invo ve the application of ? i) . the Law of Conservation of Energy ()1 Graham’s Law RMurphy’s Law 23. Given the equilibrium constants for the two reactions shown below, what is the equilibrium constant fin: I ; 2N02(g) <—) Nag) + 202(3) Kc=? NO 4,—9' )5 N g+\309 “fit Given: 1/2N2(g) + 1/202(g) H N0(g) Kc=4.8X 10““ f 15". 2N02(g) (—) 29pm) + 02(g) Kc= 1.1 X 10—5 ZNOjf Dig—5 ijtlfiDg 1" Z — - - no to —s t 4 I 13 13 ¢ (1) 4.4x 10 (2) 2.3 x10 (3) 4.6)( 10 fix}? I (s) 4.3 X 10 M93, W12 24. ' tis the Kc express' for the reaction: C0(g)\+ 3H2(g) §r-b CHAng 0(1) ? y } [collflzl3 WCOHHE (3) [CH-4] 2m [CHdl—HZOL [CH4] [lelHiol [CPL] [collel [CollTHzl3 [CONE]; 25. What is the [H'] in a solution with a pH of5.73 at 25°C? l‘ 'ff ‘0 (1) 0.76M (2) 5.4x 105 M (3) 13 X 10'5M (4) —5.?3 M (5 1.9x 104M 26. fleasolution described in the problem above would be classified as ? : ( yacidic (2) basic (3) neutral (4) isotonic (S) heterogeneous a: “qt _ . .ir' 1‘1. _\ 2?. What is the pH ofa 0.025 M solution of calcium hydroxide?“ Lab“); 32mg \ ‘ Q30 010 qt? ‘ (l) 1.3 (2) 1 X 10”” ® 12.4 (4) 12.7 0" / (5) 13.975 . A 28. At 10°C..the value of Kw for water is 2_.9__X 10"_‘_5. What is t if pure water at 10°C? 10 a (1) 1.0x10‘? ' “(2) 1.0 x10“ (3) 2.9 X10191 (3) 1. :x 10*” ® 5.4—?10‘s )l llcl X \D-ls 1: 29. The change in the Kw value for water from the value at 25°C used in c and on'homework problems to the 10°C value described in the problem above ' plies that the water ionization reaction is _? _ 9. if _ (Bjexothennic endothermic unpredictable non-equilibrium - ' (5) in violation of Le hatelier’s Principle ' ' a l/ Jl l) ‘30. What is the m in a 0.0 o M solution ofammonia? NH; +1304; N H“: OI ‘0 C (1) 1.0x 10—“ M 7.5 x 10*“ M (3) 1.3 x 10—3214 (4) 1.0 x 10 T M y _. (5) none of theSe, beca there is no HJr in a solution of ammonia ' 1 0.001 lib/“fl -': __L_. TURN IN YOUR SCANTRON SHEETS. KEEP YOUR EXAM '03 I) A KEY TO THE EXAMINATION WILL BE POSTED IMMEDIATELY AFTER Jig THE ' . — 1% H2O +9 oqtg tab . 1.1 ' ' At : \ ll \0 f - ‘ “I : ‘ K .N M e .. [ofij "1 QY l0 5 35:17 W ©\ 5 ._ N 9‘95“me 1uc Exam -—‘-—‘L.Jf~J'JI “99°34? mamm— 11. 1 12.1 13. 5 14. 3 15.1 16. 1 1?.1 18. 5 19. 1 20.1 21. 2 22. J. 24. 25. mmh— 26- 1 27. 4 28. S 29. 2 30. 2 ...
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C111PF07T3 - N 1 {V1 574“? ‘9:- Sdr 075-0 fl‘néowé...

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