Exam 1 - Spring 2010

Exam 1 - Spring 2010 - “New!...

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Unformatted text preview: “New! httsz/leamuhedu/webct/urwflcl l29457039021.tpl 12946001602”... Title: Exam I Started: February 23, 2010 5:22 PM Submitted: February 23, 2010 6:42 PM . Time spent: 01:19:46 ' Total score: 14/20 = 70% Total score adjusted by 0.0 Maximum possible score: 20 10ft: tot?" Stir-F Just-i, (if “7,.th ,4" Which type of intermolecular force ("interparticle force") is the most important in CH2CI2(I)? Value Correct Answer ./ Ion-dipole forces 4. Ionic bonds 5. Hydrogen bonds Score: on Which of the following substances has the lowest vapor pressure? Student Response Value Correct Answer fl 1. HF LVJ‘V‘HI (‘S'f' {‘V‘f‘g .1000/0 a liter 775$ W‘JhFS—i "\{E was _. . N; II. .l-tC How much energy in J is needed to convert 17 g of solid ethanol at -145 °C to liquid at 407°C. " "I L fYou might need to know that: gad— n_ m C m L m limflflq L flu S F1106. mp = '114 0C and DD = 73°C Fflb- air/girth?" h C ‘7 I..>< tCoC: —.. FIDO The heat of fusion is 4.6 kJ/mol and the heat of vaporization isL 15.0 kJ/mol. ‘- Egg-33 H 1 W "L, )t 5,9; Finally, the specific heals of the solid, liquid and gas are, respettivLély 2.1, 3.2 and‘1.8'J/g °C. _-{_r —-— 31gb. 5) 3’ 2 Wm Q-Ill Student Response Value Correct Answer ,Ib,d$/;-Wg-.-.__w_ ___._ m1 21’261’2010 7:40 AM View Attempt ' hltps:i/learn.uh.cdmwebc1furwflcl E29457039021tp1 094691] £50315, '5. ' ' hich of the following is indicative of the ekistence of strong intermolecular forces of attraction in a liquid? Student Response Value Correct Answer E _ _ a very low freezing point i Fiji-“71?? [CREAM ' J The “(i-“3% 1‘19 “I?” B. a very low heat of vaporization a C. a very low viscosity D. a very low vapor pressure nyggrflw C a E. a very low boiling point Score: 0 1 Ufll/l't ‘W‘W’lqs 'Vif‘VC Li? Par-'1' Y' H'fUS Vflp / 3% M I gr, ____ _ ___ __ _ _ _ __ _ _ __ _ _ _ _ _ . W Which of the following statements is true? \/ Student Response Vaiue Correct Answer A. A solution can only have one volatile co_mpor_i_e_nt._____ '{fi‘l’iffl ___ B. The freezing point depression constant is dependent on the (it‘yvCi’xC'i L: C-‘h SCH L . rHA solute present in a solution {if cmmch C. The osmotic pressure of a solution is directly proportional _ . to the mole fraction of the solvent. The solubilities of gases in liquids decrease with increasing temperature. Pain-HIE 1&4; 0H? CH 900*] E. The effect on a colligative property is 0% (1 (£me U PU!" whether a solute is an electrolyte or not. CO VIC- r: [ Pl 011%” ~60 sci merri— Sco re: 0/ 1 6. What is the strongest form of intermolecular force between solute and solvent in a solution of NaBr(s) in H200)? Wté’ Student Response Vaiue Correct Answer 1. dispersion -€ion—dipole 100% a ___. dipole-induced dipole __ _ I __ _ _ 4. hydrogen bonding __ pole-dipole low'c Score: 1/1 Q41: Which of the Following is less soluble in hexane, @haflgWr CBI‘szU). Don't try to type the subscripts. Just use letters and numbers. “Ff; digmlyfg. I; K6 l ELI-An—l- H n n u n u fin ll‘nlu:n Faun-nub Inn-pun.- E 2 of6 2.06.9010 7:40 AM View-Afici'spt https:fi'learn.uh.edufwebcfiurwflcl129457039021.th129460016021}... aluuelu HEQPUIIDC VGIUE DU! IuL'I. M1F3WCI ’ methaneL________W_WQWW lgquformrwgquals methanol (100%) E Score: 1/1 . .. . , s. s. . ._ .. .4. fl mgfwfflu H? _____ , 417w»: Calculate the molaiity of an aqueous solution that is 5.2% by mass calcium chloride. You might \/ need to know that the density is 1.18 g/mL. L-iC' 1 29,057) = ii 1 Student Response {Mm g mu kc Correct Answer 5- 0-875 . ._ _,..._:C:__Eg__issi.emt , ,,,,E:,L652_fl- ___________ .499 15:21.2: ____ _:i__e%_-‘§_ci§§-.£fe§8_ss;s, ____9____r§_e________._we.9$92,: ,,,, ,,tc:,§iiem___ _____ __ a E. 0.595 0 - 051 35 100% E J 9- '1 + 1-:— 3 \/4H0w many moles of solute particles are present in 4.49 mL of 0.161 M (NH4)2SO4? Use scientific notation with 3 significant figures!!!! L4: {1, L. Student Response Value Correct Answer and x 9. 00 1.4.4 q: . 113E — L'L Answer: 2.17E-3 100% 1175-3 (217 x 10‘3) K1 3 Score: 1/1 24—15:? :Which of the following aqueous solutions will have the highest freezing point? \/ Student Response Value Correct Answer A. 0.100 m glucose (C5H1205) fl o. BEEQEEEEZ::: Q__'if"'ffl'f.:::§;§9._Q_..j:;sw c. 0.100 m K3PO4 0°/o",l—UO | D. All have the same molality so all will have the same value. _._______ .. _ _ ____ __ _ ____ __l E. 0.100 m CaClz . ECO | Score: 0/1 {W‘OHC‘SJr ihflV‘f’ mlflhfg+ {: P! “Kc VP Calculate the freezing point (in degrees C) of a solution made by dissolving 3.47 g of '3‘ 14’] :O‘ 023 na hthalene {Clng} in 43.2 g of cyclohexane. The Kfp of the solvent is 20.1 K/m and the lag No I | f e ' ' t ' 6.5 d C. norma :- ezmg pom is egrees A716: P [m Student Response Value Correct Answer 0. 01:1 no} t Ml :1 Answer: -6.11 100% 0- 1 Scene: 1/1 CAUS— X20.1 5121/ \0.§' ‘0. k; —-' flol 3 of6 212612010 7:40 AM View Attempt 4of6 12. 14. https:/flcam.uh.odu/webctfmwilcl129457039021.th129460016021L" 3.56 grams of an unknown non-electrolytic solute were dissolved in 40.0 g of acetone (Kfp : 2.40 K/m). If the freezing point of the solution changed by -0.820 0C, determine the molar mass of the unknown solute. Student Response _ Value Correct Answer ‘ g; A. 260 g/mol {3.59 ) L140) r: 8’344 100% a .ezaememm____1gse£LJbfi$$’3"oabéiéTmmifggEgjm"l l . -9--:26.9!n10' ’ t" ; gmD-wasee1___mmm::::::::::7:::f_w”" "“”””“l H22 is a nonvolatile, water-soluble substance. When 6.15 x 10’3 mol of H22 is dissolved in 50.0 g of water (Kfp = 1.86 C’C/m), the freezing point of the resulting solution is —0.69 °C. Choose the equation that best describes the dissolution of H22. I. H22(s) z> H2Z(aq) II. sz(s) => H+(aq) + Hz‘(aq) III. HZZ{5) => 2H+(aq) + 22‘(aq) Student Response Value Correct Answer l 5.7.3.1..911'2’. l eeemwmemiififi:::::ifiI:L:7mfljmmfl_“ l C. I only .222,721,2222WW _. ., Q D. 111 only 100% M I [Leeeemwwmwflmmnm_'72"WWWW'W'W' "WW' Score: 1/1 Given the data below for the reaction, 2 A + 2 B + 4 C => D + E + 3 F, Experiment Initial conc of A, Initial conc of B, Initial conc of C, Initial rate, moi/L moi/L moi/L moi/Ls 1 0.1 0.2 0.4 2 x 10-3 2 0.2 0.2 0.4 4 x 10-3 3 0.3 0.4 0.4 2_4 x 10‘2 4 0.4 0.6 0.2 72 x 10': . Calculate the value of k to 3 significant figures. Do NOT use scientific notation! Student Response Value Correct Answer 2/26/2010 7:40 AM View-Amr-pt htqas:ffleam.1fl1.ed1flwebctlurwflcl129457039021.tp11294600l6021l... 1. .200 0% Equals 0.500 (100%) l Equals .500 (100%) 3 ---m _ __ We- . ---..-__ __ WEQHE'EEP05'1 (gem/o2. -- 3 Score: 0/1 In a first order decomposition, the constant is 0.00480 sec'l. What percentage of the I compound has decomposed after 86.6 seconds? Ly”) lCC- - k h [4H t. C. POI—JED l E (5- [{3} Student Response Vaiue Correct Answer “"5!”er _ 65-33111. . 91/? _ 3:? . , . _ _ Score: 0/1 \ GL1 — 51,115 I \n 71‘: ‘ 15. (If-Hr}- The rate law for the reaction 3A => 28 is rate = k[A] with a rate constant of 0.447 hr'l. What is the half-life of the reaction in hours? U0 2 .7 16 i: ‘92 Student Response Vaiue Correct Answer I. 4.47 _ 7” a 2. 1.55 100% a _ 3. 0.645 4. Cannot answer without knowing the initial concentration. Score: 1/1 which of the following is true for a second order reaction. I. The sum of the exponents in the rate law is equal to two. ‘- II. At least one of the exponents in the rate law is a two. I III. The half-life is not constant. / IV. The half-life is constant. 1 or M'2 min‘l. J * Student Response Value Correct Answer A. and III _ W _ I V. The rate constant, k, can be expressed as M'2 s' B. I, III, and V7 . ... 1.... .-. -......,..me_._._._ .. .. .__. . . .1. 1. m.._._ .. . _____ ._......_.._W1.,....,.,,-- _f_i'§§_lj_l§_i___é'_né iv" 7 f." :1...” _ __.. : 1:11.“; 11--.... __ __ Score: 1/1 5 0f6 2/261’2010 7:40 AM View attempt https:l!ieam.uh.edu/webctfurwflcl12945703902].th12946001602§L_ 18. Consider the reaction with the rate law, Rate = k[i3r‘03‘][Br'][H+]2 By what factor does the rate change if the concentration of 3103' is doubled and that of Bi" is doubled? Just put in the number as a whole number or fraction. Student tiesponse Vaiue Correct Answer - l 1. 4 100% Equals 4 (100%) ______EQEE'_§__4 l__1___S_1_99_‘?9)____. ___________ _ __ __ Score: 1/1 19. What is the reaction order of H+ for a reaction with the foiiowing rate law? Rate = k[i3r03,'][13"_]|:H+]2 Student Response Value Correct Answer é" 17-52253? " ’7 When/J” 3; W” Wire?" M, "7:12'" '7 "Amiff'Nii 'F'i'friém” m"m"'_"—m__:mmmmMWW AAAAAAAAAAAAA “W ______ ___ *WJI':W": , L' t W W Score: 1/1 20. Consider the equation, 4 NH3 + 5 02 => 4 NO + 6 H20. If the ammonia is being used at a rate of 0.40 M15, how quickly is the concentration of oxygen decreasing? Student Response Vaiue Correct Answer A. 0.40 M15 ,, ,,,,,,,,,,,,,,,,,,,,,,,, , 7,, ,,,,i,,,,,,w,flj _B._0.32 w; _ i i I _ e. ie E- 09503475 ’7 _i99f{e.__..i1:: " I Score: 1/1 6 of6 212613010 7:40 AM ...
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Exam 1 - Spring 2010 - “New!...

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