CHEMISTRY.142.NORMAN.WINTER.2004.MIDTERM2

CHEMISTRY.142.NORMAN.WINTER.2004.MIDTERM2 - in Winter 2004...

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Unformatted text preview: in Winter 2004_ ‘ CHEMISTRY 142A Professor Joe Norman Exam #2 50 Minutes .34 New _ TOTAL POINTS: out of 25 Name: n we mini— *** READ THIS PAGE CAREFULLY BEFORE YOU BEGIN I! *** 0 Write your name and TA’s name above. TAs are listed below: [email protected] Thursday Quiz Tuflday Lab Thursday Q1112 Tnfldny Lab AA P. Aruba m 8:30— 9:20 1030—110 . Mm 3:30—4:20 2230—520 AB 6. Villar m 9:30—10:20 10230—120 AH J. render m1 2:30-3:20 230—520 AC S. Selmbe m 8:30— 9:20 10:30—1220 A] D. Rodovsky MOM 1:30—2:20 5:30—8:20 AD D. Rodovsky Max:151 2:30— 3:20 1030—120 AJ LDagt-ir Laughs 2:30—3:20 5-30—3520 2:30— 320 130—420 1230-1-30 6:30—9:20 1:30—2:30 6:339:20 1:30- 2:20 1:30—4:20 - Verify that you have 9 questions on pages 2 ~— 3 and the periodic table as the last page. 0 No calculators, notes or other paper allowed! Use back of exam pages for scratch work before you write out answers. No re—grading for answers where there’s been any erasing. - You may use any information on the accompanying periodic table. Show numerical work. Write numerical answers with correct units and the correct number of significant figures. 0 When finished, put your exam in your TA’s stack at front. Recycle the periodic table in the boxes at front if you've torn it off during the exam. 0 Exam is over when the end-of-class bell rings. No papers accepted more than 1 minute after the bell rings. 0 Answers will be posted after the exam on the course Web site (address is in your syllabus). Exams will be returned by your TA during quiz section. 0 Grading questions: ask your TA. Deadline: March 1. If you request any re—grading, your TA will re-grade the whole exam: your grade may go down, go up, or remain the same. 0 as constant R = 0.082 L-atm/mol- / MOW - W3 - e, " Chem I42A, Winter 2004, Prof. Norman, Exam #2, Page 2 vi , Wm ' - a“ v3 d M 1. (5 points). Fill in blanks. Listed below are 6 gases followed by 9 properties. Write next to each gas the letters for all properties that are correct for it. b e I. co. Jig...sz W0 l: i N02 ‘ H A I: 02. .—— .L___._+._._4__.__ g3. 1: so; 9.0.; 03 >1 % of the volume of pure dry air at sea level. protects life on earth from incoming high-energy solar radiation. formed by decomposition of proteins. substances that destroy this gas are banned by international agreement. no worldwide agreement has been reached to limit production of this heat-producing gas. reactant in 2 of the 3 reactions that form photochemical smog. . 3 RT. the major source material for acid rain. 3 IZT E k ' ’Z the most common oxidizing agent. 0., ’7— EL4 : kit‘s—("3 R at 300 K, 1 mole has kinetic energy > 400R. ' _-———-—_----——-y—q—-o--—---~--_—-_-_.___—_.—————---_—-—-—_-—_-_a_-_-—-_-—--__-_—----nap—’--—_-_-_o-.n-—_’—---n-pq.— waeempowo Questions 2-—4 refer to the following data: . 58.7. g nickel (Ni) metal dissolves in aqueous sulfuric acid at STP, producing 22.4 L of a gas and a blue aqueous solution. 0.25M lead nitrate is added to the blue aqueous solution until no more white solid forms. A green aqueous solution remains above the precipitated solid. 2. (4 points). Write balanced equations for the two reactions. Include phases of all substances. Write dissolved ionic compounds combined [example: KF(aq), not K+(aq) + F(aq)]. Mmmmk Hugh nzxnogD-a manggo e “295 A” ReactionZ: [\linglg3-l-2Pb “'5 r Phgéafi (5‘) + NECMOE')2(G¢§3 3. (2 points). Fill in blanks. Which elements are oxidized and reduced in reaction 1? What are the changes in oxidation number? N! is oxidized fiom O to *1 . l’Q is reduced from H to O 4. (I point). Show work. What volume of lead nitrate solution is used? 30 far" v' .5": 12% 2v 2. EE Fh‘h-h-F‘F--_-—-—-------¢hi—---F---------—-------—-q---hflhd---‘-nfi------—-—------------h-n-H-b-n-hind-q-qfl—flhn- lo: a a Chem 142A, Winter 2004, Prof. Norman, Exam #2, Page 3 Questions 5 and 6 refer to the following data: Aqueous ammonium carbonate is neutralized by titrating it with aqueous barium hydroxide until no more white solid #1 forms. All water is then evaporated; the other gas that remains (besides water vapor) is collected. This gas is mixed with hydrogen fluoride gas until no more white solid #2 forms. The white solid #2 has a mass of 7.4 g. 5. -\ (4 points). Write balanced eguations for the two reactions. Include phases of all substances. Write dissolved aqueous ionic compounds combined. Reactionl; (Mng Cog (£3 + 36.6“): (as JDfZM—lg (:5 M43091). t Sufi-05 (s) ' M 3 HFL 27 H F Ls Reaction 2: (2 points). Show work. If we collect the gas from reaction 1 in a 0.82 L flask at 300 K, what is its pressure? m0 PU an ‘6“? «(N/10“)? Digiti Iogz(3da> fl/{o P “r” M i so“ at “*1 n-m-—m——-—-——-—-———-—-.-_..—.-—-.-n.--.—-u—~p—pu‘m—n-o-——-—--——_-"—--..-.o-"—.—_-_...-_-——.--——-—-----—-—--—-—- 7. /\l’l/ (2 points). Show work. At constant 1‘, HF(g) is pumped into a sealed, previously evacuated container of Y_ = 8.2 L. Throughout the pumping, the pressure in aim inside the container stays at 3.0 times the number of moles of HF inside the container. What is I in °C? W: 0?: 9200 am) a a cords“) \ / T 2 ' ’50? '2’ T: 9" ‘ofig’ 300 I .312/ . (2 points). Complete and balance the following reactions, an mdicate the pH of the final solution by writing “>7”, “<7”, or “= ” in the blank to the right of the reaction. Write dissolved ionic compounds W! a. CcholeMaq) + HN03(aq) AQCH3CDZGey on“ {003664) pH 5.7.. 1:. Nazsoaaq) + H20(l) = W? 7* H gott' t 0H gs} gt» “ml “*5 (3 points). Complete and balance the reaction below in acidic solution. Include phases of substances that you add to either side of the reaction. V(s) + econaq) -—> voz*(aq) + . althk} a”: Cl)“ -——'9 Ct" [63 ant-W (U A Jbu} was): \2 tom (009:4? qgawt ‘ Zv J:ch— \anxjo‘ft tctf‘ - 1 at} -+-ctoqg+k\r\30+ as “om ci’t [peso 4 CHM) a f *M.-. u s. w 7,th +¢l0t;étfi5¥lluga+(fiq)‘5 ZVOZWMD 4 CF" («0+ lé H1002) ...
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This note was uploaded on 03/03/2010 for the course CHEM 142,152,16 taught by Professor Unknown during the Spring '08 term at University of Washington.

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CHEMISTRY.142.NORMAN.WINTER.2004.MIDTERM2 - in Winter 2004...

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