Test3a_Spring_2009 - View Attempt View Attempt 1 of 1...

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Unformatted text preview: View Attempt View Attempt 1 of 1 Title: Exam 3 Started: April 28, 2009 9:48 AM Submitted: April 28, 2009 11:04 AM Time spent: 01:16:17 Page 1 of 10 Total score: 17/20 = 85% Total score adjusted by 0.0 Maximum possible score: 20 1. https://sch01ar.uh.edu/webct/urw/10261766704.tp261766721/ViewStudentAttemptdowebct?... Chapter 11 S Ksp 31 At 25 0C the solubility of copper(II) sulfide is 1.71 x 10‘16 mol/L. Calculate the value of KSp at this temperature. Give your answer in scientific notation to 2 SIGNIFICANT FIGURES (even though this is strictly incorrect). Value Correct Answer 100% Equals 2.9e-32 (100%) ; Student Response 1. 2.9E—32 iml General Feedback: Score: K —52 sp 1/1 CIE 5 What is the solubility of silver chloride (KSp = 1.1 x 10'10) in a solution of 0.15 M magnesium chloride? Student Correct ; Response Answer ifiia. Feedback 3.7 x 10" 100% a 10 - 3.0 x 10‘ 0% 4 - 7.3 x 10' 0% 10 d- 4.9 x 10' 0% Chapter 11 Precipitate 1 The K5p of AgCl at 25 °c is 1.6 x 10‘“). Consider a solution that is 1.0 x 10‘5 M NaCl and 5/1/2009 View Attempt Page 2 of 10 1.0 x 10'5 M AgNO3. Student Correct Value Response Answer l Feedback E 1. Q > KSD 0% l and a t precipitate I I will form. 2. Q > KSp 0% and a precipitate will not form. E3 3. Q < Ksp 100% a and a precipitate will not ____f9r_m_-_. __ 4. Q < K5p 0% and a l precipitate I will form. | 5. The 0% ; solution is ' LfljflL ____ __ Score: 1/1 4. Serial Precipitation 12 A solution is 0.30 M AgNO3 and 0.10 M Sr(NO3)2. If solid Nast4 is added to the solution, what is [Sr2+] when AgZSO4 begins to precipii:ate?(KSlD SrSC)4 = 3.2 x 10‘7; A92504 = 1.1 x 105) Student Correct Response Value Answer Feedback & a. 2.6 x 10' 100% E C- 5.7 x 10‘ 0% i 4 d- 1.2 x 10' 0% 4 https://sch01ar.uh.edufwebctfurw/lc261766704.tp261766721NiewStudentAttempt.dowebct?... 5/1/2009 View Attempt _ Page 3 of 10 e- 3.2 x 10’ 0% 3 6 Score: 1/1 5. pH Solubility 1 Which of the following compounds will not have a different solubility with a change in pH? I Student Correct g Response Value Answer Feedback £51 1. AgNO3 100% E l .. 7 I 2. Ca 0% I 3 (101504)2 % , _ r V I a ' 3. SrCO3‘ 0% I 4. CLIF 0% i 'L 5. Gus 0% Score: 1/1 6. Sign of Delta 5 4 AS for the following process is positive. True or false? Hot air expanding. Student V I Correct Feedback l l Response a He Answer :53 1. True 100% a 2. False 0% _;__.__-J 7. DG = DH - T DS Qualitative 7 For a certain reaction the standard free energy change is +20.0 k] at 300 K and —20.0 kJ at 600 K. For this reaction 1 StUdent Value correct Feedback l 1 Response Answer £1 a. AH is 100% a l positive 1 I https:f/scholar.uh.edufwebct/urw/lc261766704.tp261766721NiewStudentAttempt.dowebct?... 5/1 /2009 View Attempt Page 4 of 10 and AS is positive. b. AH is 0% negafive and AS is negafive. c. AH is 0% negafive and AS is positive. d. AH is 0% positive and AS is negative. e. Impossible 0% to tell Score: 1/1 8. Laws of Thermo 19 The Second Law of Thermodynamics states that _ WW.M.‘._.._. .1 Student Value Correct Feedback Response Answer | a. if AG ofa 100% fi reaction is negative, the reaction is spontaneous " 5. heat is 65/} ' energy c. energy is 0% conserved in a spontaneous process cl. all of these 0% are valid statements ofthe second law. @ e. none of 0% these is the I second law. Score: 0/1 https://scholar.uh.edu/webct/urw/ICZG176670411326176672lNiewStudentAttempt.dowebct?... 5/1/2009 View Attempt Page 5 of 10 9. SandHtoT9 The reaction between ammonia and dinitrogen trioxide to give nitrogen gas and water, NH3 (9) + N203(g) <=> N2(g) + H20(g) has a AH value of —700.0 k] and a AS value of —7 kJ/mol K. At what temperature does the reaction become non—spontaneous? l E Response Answer FeedbaCk E 8 100°C 0% l _ 1 la: b. -173 cc 100% a g c. 100,000 0% i K E is «1:173. K 0% , l l e 0 00/ ‘ immilwimml MMMMMMMMMMMMMMMMMMMMMMM 1W .......... M, .............. , 111.1} 10. Test Prod — React 13 Using the given values, determine the value of AG° for the reaction, 2 NH3(g) + 5 F2(g) —> N2F4(g) + 6 HF(g) AGfO values (kJ/mol) NH3(g) = —16 N2F4(g) = 80 HF(g) = -275 l Student Correct V H l Value i , Response Answer ; i l a. -1538 kl 100% fi B._;1,,7,9kJ_ 0% _ E : 64602 M 0% , __ , , _ _ ,, _ otaeliéii k] (5%,» z _ 4 ,_ _ __ _ , j e. 1602 k] 0% M M“ Score: 1/1 11. Delta G Combining Equations 2 Given the following data, 2 NO(g) + 02(9) => 2 N02(g) AGO = -73.9 N2(g) + 02(9) => 2 NO(g) AGO = 171.8 https://soholar.uh.edu/webct/urw/10261766704.tp261766721NiewStudentAttempt.dowebct?... 5/1/2009 View Attempt Page 6 of 10 2 N20(g) => 2 N2(g) + 02(9) A60 = -211.4 Find AGO for N20(g) + N02(g) => 3 NO(g) l Student Response Value Correct Answer Answer 103.05 100% 103.1 Score: 1/1 12. K to DG 8 For the reaction N203(g) <=> N0(g) +N02(g) AGO = 5.5 k] at 60°C. Calculate Keq at 60°C. ‘7 Student V I Correct Feedback Response aue Answer a. 0.137 100% a b. 0.998 0%” ' I "35.3in 7 0%: l d. 1.63 x 0% 10'5 13. Non Standard G 4 The value of AG0 for the precipitation reaction, Ca2+(aq) + CO32+(aq) <=> CaCO3(s) is —48.1 id at 298 K. Calculate the value of AG in k] at 298 K if the concentrations of Ca2+(aq) and CO32+(aq) are 4.81 and 8.10, M respectively. r_____—____________ Student Response Value Correct Answer l l i i Answer —57.174 100% —57.2 Wm. M... .c hmm_mmmmwmmwmw Score: 1/1 https://scholar.uh.edu/webct/urw/10261766704113261766721NiewStudentAttempt.dowebct?... 5/1/2009 View Attempt Page 7 of 10 14. Balance Redox Base 19 Balance the following equation in basic solution using the lowest possible integers and give the coefficient of hydroxide ion. Cr(OH)3(s) + CIO‘(aq) _> Cr042’(aq) + cr(aq) l- gggggggew... ggggg Feedback ' i 1.1 0% is"? 0% , 1%] 3..- .4. , 100% ,5 1 4. 2 I 0% 5.0 0% . Score: 1/1 15. Chapter 12 E0 values 146 Determine E0 for the following reaction, using the given standard reduction potentials: Fe(s) + Mn2+(aq) —> Fe3+(aq) + Mn(s) E0 for Mn2+(aq) = -1.18 v E0 for Fe3+(aq) = -o.04 v Do not put in units. Student Response Value Correct Answer i E D . _ o quals -1.14 (100 lo) il‘ 1'14 100 ’° Equals -1.14 (0%) Score: 1/1 16. Redox Agents 3 Identify the oxidizing agent and the reducing agent in the reaction. 301(5) + 8H+(aq) + 2NO3'(aq) —> 3Cu2+(aq) + 2NO(g) + 444200) Response 6 ue Answer 1. oxidizing 0% J agent: i Cu; . 3 reducing : 3 agent: = l https://scholar.uh.edu/webct/urw/ché1766704.tp261766721NiewStudentAttempt.dowebct?... 5/1/2009 View Attempt Page 8 of 10 N03— 2. oxidizing 0% agent: H+ . reducing agent: 5%] 3. oxidizing 100% a 5 agent: N03" ; reducing agent: i Cu _ 4. oxidizing 0% agent: i — . . NO3 , reducing agent: H+ Wm.“ Score: 1/1 17. Oxidation Number 2 Which of the following contains CI in the lowest oxidation state? I _______ __ I Student Correct f Response value Answer FeedbaCk i a. sodium 0% , perchlorate i b. sodium 0% ; chlorate l c. sodium 0% chlorite I . 5 d. sodium 0% hypochlorite %@ 8. sodium 100% a ' chloride Score: 1/1 18. WA/SB Titration 16 Determine the pH of a solution in which 40.0 mL of 0.2 M aqueous formic acid (Ka = 1.8 x 10“) has been titrated with 30.0 mL of 0.2 M KOH. https://scholar.uh.edu/webct/urw/Ic261766704.tp261766721NiewStudentAttempt.dowebct?... 5/1/2009 View Attempt Page 9 of 10 {. sweegmmmwfi i figfig'eoztse Value Eggs}: Feedback é a. 3.27 0% b. 10.73 _ 0% 1] l c. 2.22 r 0% ‘ ' d. 9.78 0% l E] e. 4.22 2 7 100% m7” 7 Score: 1/1 19. WA/SB 1/2 EP 4 Determine the pH of a solution in which 20.0 mL of 0.2 M aqueous acetic acid (Ka = 1.8 X 105) has been titrated with 20.0 mL of 0.1 M NaOH(aq). fir,.,fifif_mfi_______________ .. _.__. . _ . Student Correct i Response value Answer FeedbaCk ifi] a. 4.74 100% I: l 0% ' l c. 2.72 0% I d. 11.28. 0% l i 2. .mm.._.,2_..m._ ...M.m_.m._____ _.__J Score: 1/1 20. Making a buffer 2 Which of the following mixtures would NOT be described as a buffer solution? Student Correct I 1 Response Value Answer Feedback 1 l l l a. 0.25 M 100% a : HNo3 l I and 0.15 M KNO3 . b.015M 0% l NH4Cl ' and 0.25 M NH3 l l l . . l c. 0.20M 0% l https://scholar.uh.edu/webCt/urW/1026I 766704.tp261 766721NiewStudentAttempt.dowebct?... 5/1/2009 View Attempt Score: iDone NaOH and 0.40 M CH3COOH . 0.25 M 0%6 HNo2 and 0.15 M KNO2 . 0.30 M 0% NH3 and 0.15 M HC1 0/1 Page 10 oflO https://scholar.uh.edu/webct/urw/ICZ61766704.tp261766721NiewStudentAttempt.d0webct?... 5/ 1/2009 ...
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This note was uploaded on 01/29/2011 for the course CHEM 1332 taught by Professor Shiv during the Spring '08 term at University of Houston.

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Test3a_Spring_2009 - View Attempt View Attempt 1 of 1...

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