Practice Exam 1b CHE102

Practice Exam 1b CHE102 - Chemistry 102/112 1st Hour...

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Unformatted text preview: Chemistry 102/112 1st Hour Examination February 25, 2005 3a INSTRUCTIONS: Mark the best answer (A - E) to each of the questions below on the separate answer sheet provided. Each of the 25 questions is worth 4.0 points. 1. Which of the following statements is FALSE? (A) diffusion occurs in both gases and liquids (B) liquids and solids are virtually incompressible ‘ (C) a solid is always more dense than its corresponding liquid (D) atoms in solids are always vibrating . (B) it is possible for a solid to be converted directly to a gas upon heating 2. Which of the following gives the correct order for boiling points? (A) He<H2<F <HF<HC1 NO (B) H <N2 -® 131'2 No E (C) H 0 H28 < H28e < HzTe ND (D) PH3 < ASH3 < SbH3 N O (E) He<H2 <'F2<HF <NaF 3. What are the coordination numbers fo Na‘ NaCl (fcc)@i CsCl (bcc)[Cajn ccp metallic calcium? 6 g ' 2' (A) Na=6; Cl=6; Ca=8 (B) Na=8; Cl=6; Ca=12 E (C) Na=6; Cl=8; Ca=8 (D) Na=8; Cl=4; Ca=12 (E) Na=6; Cl=8; Ca=12 4. [Based on homework 11.62] - I Crystalline KCl contains 4 "formula units" in a unit cell whose cell edge IS 628 pm. From the density of KCI (1.978 g/cm3) and its formula mass (74.55), calculate Avogadro's number. Your answer is: b = M/\/ '3 no r (A) 6.06x1023 (.6173 = (wmfyflz/ (B) 6.14x1o23 'TEn/fi/ [ N 62“ I (C) 6.20x1023 3 D (D) 6.09x1023 _ \ 4474,53” low] (E) 6-12x1023 N "' 1.373 52.? 13 2: 6,0?69 (3'76 7(10 6.07 4a. Chemistry 102/112 5. Look at the Phase Diagram for H20. Identify the following: (A) (B) (C) (D) (E) Which is a covalent—network solid? (A) (B) (C) (D) (E) The AH value for a gas dissolving in water is usually negative, because: (A) (B) (C) (D) (E) Which of the following is the most soluble in CC14? (A) (B) (C) (D) (E) triple point (TP) critical point (CP) gas phase (G) liquid phase (L) solid phase (S) TP=4, TP=2, TP=5, TP=2, TP=4, sodium Buckminsterfullerene ("bucky-ball") CP=5, CP=5, CP=5, CP=2, CP=2, diamond water solid oxygen G=6, G=1 , G=3, G=1, G=6, L: , L: 5 L=1, L: , L: , 151 UJUJMUJUJ Hour Examination February 25, 2005 one of the two endothermic steps (separation of solute) in the solution-formation process is unnecessary gases always react endothermically with water neither of the two endothermic steps in the solution-formation process is necessary all three steps in the solution-formation process are exothermic all other answers given are incorrect CH3CH20H H20 NH3 C10H22 NaCl ' Chemistry 102/112 9. 3 10. (3 12. 13. 1st Hour Examination February 25, 2005 5a OJCIOL... The solubility of MnSO4-H20 (formula weight = 169.0 g/mol) is 70.0g pe IOOmL f solution at 20°C. A solution of 4.22M MnSO4oH20 at 20°C is best described as: (A) solvated 4,22ml> j 0 . (00L) supefiturzted ( I L— unsa ae . a : 7l-3lS/3/ o o swiww “1* (D) saturated (E) hydrated The molality of a solution prepared by dissolving 2.2] g potassium bromide in 897g water is: ’m 2: Wu:\ KSC/Raa HLO (A) 0.246 (B) 0.0167 2, 2\ (‘ | M\ K30 {0150 L (C) 0.0207 W (D) 0.0186 857% “10W \ :3 (E) 2.07x10'S Q Which of the following has the ,Iowe freezing point? , (wax/3&1" 2: (Cw/n3 (A) 0.60m aqueous glucose [‘5 o. (,0 r; 0 ~ Q Q (B) pure water —— (C) 0.90m aqueous sucrose I ‘2‘ 0' (to 7" o' (I: (D) 0.24m aqueous FeI3 4+ *6 o. 'Lq/ 1' O - Z O /‘ (E) 0.50m aqueousKF 2 ~g 0. S13 -’- l v The freezing point of ethanol is —114.6°C. If Kf for ethanol is 2.00°C/m, what is the freezing point (in °C) of a solution prepared by dissolving 50.0g of glycerin‘(C3H303) in 200g ethanol? (A) —1150 AI = L" “(l3 in 2TH 1+1» (B) —1327 7; {0. 0% G—Lj )(l Mel Gal [5803 >: 2’7. (C) —5.42 m ET“ 72.073 @431 MC‘ _ .0 H9 M = ' l 0 E53 -328 m“ ==(1)~<<2 jut—LMXZ ~00 CI (:71: we .a- u’ ’- 17; z (a 104.13%) — (A. Ll—lcl C1) The osmotic pressure of a 0.100M solution of aluminum chloride at 27°C is: AWL; —-/~ MELZCI i=9) (A) 2.46 atm (B) 24.6 atm ,__ r M ({T‘ -—r—: 300 K (C) 0.222 atm 7i. ’ L {M (D) 9.85 atrn I a o. [GOMl 0.08105 Lox (E) none of the given answers ’- l l— t K 65 Chmnfifly102H12 14. B 16. 1st Hour Examination February 25, 2005 Nitrogen dioxide decomposes by the reaction 2 N02 —> 2 NO + 02 If [N02] drops from 0.0100M to 0.00650M in 1005, what is the rate of appearanCe of 02 (given in units of M/s)? w h. 1 (A) 3.50x10'5 ; ____J_ A LNOL ’ (B) 1.75x10‘5 At 2 At M (C) 7.00x10'5 ‘ lb -_ .0 l _ (D) 3.50x10‘3 __ __L_ C O . Dogs 0 DC} (E) 7.00x10'3 2_ [6—0 E .- S, S l . 7 S" 7< I 0 M s . First order reaction rate constants have the units (A) M s" (B) s’1 (C) mol/L (D) M-1 5-] (E) L mol'1 5'1 The reaction A + B —) C +D is followed by the "method of initial rates" and these data are obtained I inm- Thc rate law for the reaction is: G i L(. (A) k[A][B] (B) 4k[AJ[B] (C) k[A][B]2 (D) klAflB] (E) ktAflBf Chemistry 102/112 17. C 18. 19. 1St Hour Examination February 25, 2005 721 Data for the reaction A—)B are plotted and it is found that a plot of ln[A] against t is non—linear and that a plot of 1/[A] against t is linear. What order is the reaction and what is the slope of the linear plot? (A) insufficient information is given (B) lst order, +k (C) 2nd order, +k (D) lst order, -k (E) 2nd order, —k The half-life for the overall first-order reaction k ___ 0.6?3 : 0.6?3 11.511510 Y“ % {a is 4.5x 109 years. A rock contains 297 atoms of lead—206 for each 1000 atoms of uranium-23 8. Ass'uming all atoms began as U-238, how old is ti rock? {L k M6410 atom =~(1641<10“<f9E 1245\7 _> ___o,aéoo§ ="("§L““lo \l i:- 0.1599? __ G) g g I := _.._.———-—-:'"" __ ~— , In the energy profile of a reaction (graph of Energy vs. Reaction athway), the species at the maximum on the curve is called: uranium-238 ——> lead-206 (A) 1.5x10“°y (B) 1.7x109 y (C) 8.5x108 y (D) 1.9x108 y (E) none of the other answers (A) the product (B) the activated complex ‘ (C) the activation energy (D) the main reactant (E) the stable intermediate The Arrhenius equation is k = Ae‘Ea’RT The frequency factor is designated by: (A) A (B) k (C) Ea (D) R (E)6 8a Chemistry 102/1 12 1st Hour Examination February 25, 2005 21. Overall reactions and their rate laws are listed below. Which reaction could go via a single elementary step? (A) 2A—>P rate = k[A] (B) A+B—>P rate = k[A][B] (C) A+2B—>P rate = k[A] [B] (D) A+B+C—->P rate = k[A] [C] (E) 'A+2B—>P rate = k[B]2 22. The equilibrium constant for reaction (1) is K. What is the equilibrium constant for reaction (2) at the same temperature? (1) soz+1/2 02 —> so3 (2) 2 $03 —> 2 802 +02 (A) K2 (B) 2K (C) 1/214 (D) 1/1<:2 (E) —K2 23. The reaction H2(g) + 12(g) = 2HI(g) is allowed to come to equilibrium, where the partial pressures are: 0.15 atm for H2, 0.033 atm for 12 and 0.55 atm for HI. The value of KI, is given by: (A) 23 '(f) : (PHI); (0.55/QM)?— (B) 111 ; _____:_:.___———- E zilixlo3 [DHL (s “(w)(0.033o w) e 6'1 w- 6 ( t l 1 24. Consider the endothermic reaction: CaC03(s) ‘——~ CaO(s) + C02(g) Le Chfitelier's Principle predicts that the number of moles of C02(g) may be increased by: (A) removing some Ca0(s) (B) adding more CaC03(s) (C) increasing the temperature (D) decreasing the temperature (E) increasing the pressure J Cher'nistry 102/112 1St Hour Examination February 25, 2005 9a 25. The effect of a catalyst on equilibrium is to: (A) increase the rate of the forward reaction only (B) increase the equilibrium constant so that products are favored (C) slow dOWn the reverse reaction only (D) shift the equilibrium to the right (E) increase the rate at which equilibrium is achieved without changing the composition of the equilibrium mixture ...
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Practice Exam 1b CHE102 - Chemistry 102/112 1st Hour...

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