chem 6BL old test

chem 6BL old test - SCORE: Chemistry 6BL EXAM #1 FORM B...

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Unformatted text preview: SCORE: Chemistry 6BL EXAM #1 FORM B Winter Quarter, February 12, 2007 University of California, San Diego cull Please complete and sign — Permission to post my Final score online using my lDii? NO __5 m ID. Number Name (printed) Lab Section TA ',. Name (signature) DIRECTIONS DO THIS FIRST 0 This Exam is designed to be taken with a Scantron® answer sheet. You must use a #2 lead pencil {not pen!) to take this part the test. For your test to be scored properly, you must blacken the circle for "TEST FORM" CED! it is a good idea to also write Form B on the right side ofyour answer sheet near your name. Be careful to write only in the open white areas. I- Write your student ID number into the boxes on the right side ofthe "ID NUMBER" field with the last digit in the iast box. Next, darken the bubbles in the ID field corresponding to each digit. Blacken the (:1: bubble corresponding to the "A" in your ID number (Le. "A" = "1"). If you make a mistake. carefitlty (and completebr) erase the undesired mark. If your student ID field is not coded correctly, we may be unable to determine which test paper belongs to you! I LEAVE THE "EXAM NUMBER" PART BLANK. {This is not relevant to this Exam.) c Write Your Name and Your Chem 68L Section Number (in Hoar/Day) at the top ofthe Scantron®. - There are a total of 13 questions in this test, each of which contains 4-5 responses. A list of relevant equations, a periodic table and scratch sheets are provided on various pages ot‘this examination booklet. ! M'ARK YOUR SCANTRONSHEETS 0 Use only SIDE l of the Scantron® sheet. When you have selected your answer, blacken the corresponding space on the answer sheet. Make a heavy, full mark, but no stray marks. If you decide to change an answer, erase the unwanted mark very carefully. 0 Any question For which more than one response has been blackened (i.e. "over-voting") will not be counted (unless the answer's intent is clear, which it often isn't...). it There is only one correct answer to each question in this exam, and there is no penalty for incorrect responses. You should answer every question; guessing is better than not answering. READ TIHS NEXT 0 You wr'fl not be allowed to take your examination booklet with you when you leave the testing room. However, you are encouraged to aISo circle your answers in this examination booklet - it will be returned to you later on. This exam is the property ofthe instructor. All rights reserved. NOTE: Incorrectly marking your Seantron in any way can lead to partial or total loss of points. Chemistry 6BL EXAM#1 COMMON FORMULAS & VALUES Exgerimem #0.- Exgerimenfs #I & #5: If A38}. 2 z A + y B, then KSp = [A]Z[I3]y = [zxx]z[yxx]" Exgerimenrs #2 & #445: [titrant]x(volume titrant) : [analyte]x(volume analytc) (mass acid standard : g) Molar Mass (acid standard: g/m01)= [b s ]( 1 (me L) a a v0 umc ‘ I _ [H*][A‘] K _ [B'HOH'] a " b — [MA] [13] K“. = Ka x Kb= 1.0 :-<10'l'1 pH = -log[H+] = 14 -pOI-l pKa = -log[Ka] Exgerimem #3 .' q = m c AT = n Cp AT cwm, = 4.18 J/K-g; CW3, = 75.3 J/K-mol Clook] = 'Qllot Cmclal z 26-0 JKK'mOI Cp=c x M.M. Exgerimem #46: 100W 1 1,, A = log[ [mfg] = log[}—] = 10gb?) 1 10" Beer's Law: A = sbc (where E = Molar Absorbtivity (in M'lcm'l), b = cell length (usually 1.0 cm), and c= concentration) T= “00% ExQerimem #6: c=vxk (c=2.998x108m/s) 13:th (h=6.626x10'34J-s) . : RJ 1 1 For Hydrogen: I:=AE = +1312.75—- x —2 - -—7 mol nf ni R” x h x NA = +1312.75 kamoI (NA = 6.022 x 1023 molechol) Nameflfl Chemistry 63L - EXAM #1 Seetionw__TA Winter 2007 - Form B Circle the letter of the best answer for each question. When you have selected your answer, then hlaeken the corresponding space on the Seantron sheet. "Short" Questions (3 points}: I) 2) Considering significant figures, what is the answer to l 15.12 x 7.342? a) 350 b) 345 c) 345.2 d) 345.21 e) 345.211 Which of the following tend to form salts that are soluble in water in most or all cases? a) N03— d) a& e .3) OH’ 0) (:1— ,e) b & c What is the proper relationship between pKa and pH? a) pK;l = pH b) pKa =pH + log([H%]f[HA]) c) pKrI =pl-l + log([A']f[I-IA]) (ll—.0314 = P” - 109([I‘VW'1AD '_e). plia =pH ~ log([A‘]z’[HA]) 4) 5) Which of the following substances has the largest "cooling capacity", based on its heat capacity? a) lead d) Styrofoam® b) Pyrex glass water 6) aluminum Which of the ligand types is lot a "cheiating" ligand: b) Bidentate c) All ol‘these are "chelating" ligands. a) Monodentate e) Tridentate d) I-lexadentate "Long" Questions (5 gointsl: 6) Using the calculated standard deviation (6') of the following values as the basis for 7) 3) 1017] “3.11 L . lmol 9) m” _ r, mil?) (rp- i’l‘. L", i "it L'I' wt 1'] ---ajj7.£35.6% & 89.5% 7a) 35.6%& 10.5% ‘55 7 107.5%: the determination, which of the answers below is the best value for the error of the average ol‘these values: 492, 451, 515, 446, 476? a) 25.6 b) 29 (9323.7 d) 30 e) 26 7w twi— 7-‘1'it--"i.“_u°4 t-“xI-J- 1' -' l (.4 :r' - ‘= " 1 {Ali-r‘i;{i’.- “ill M"‘i(-,-"l ’5 "'1 {lira-"Ii (5"? r‘: l 1' 11'1‘7-(1- I’- '_'.>31-/ rr A sample of copper(1) azide (Cu(N3)), containing copper(l) chloride (CuCl), was placed in a test tube. The CuCN3)fcopper(I) chloride mixture in the tube was then heated, prompting the following reaction: fCu(N3)(s) + x CuCl(s) é» :'-Cu(s) + ;Z.N2(g) + x CuCl(s) During this experiment, the following data was collected: Mass oftest tube = 15.213 g 0” (“05° kw l 1 W! I ? Mass of Cu(N3)fCuCl mixture + tube = 22.449 g (v /(.___ (1 I'rr' 1 a. '- ' Mass of CquuCI residue + tube = 20.23] g What was the weight% of azide (Nf) in the original mixture, and what was the weight% of the CuCl in the original mixture, to 3 significant figures? (Molar masses - Cu: 63.55 gilnol; N: 14.00 gtmol; Cl: 35.45 g/mol.) b) 23.7% a 40.3% c) 23.7% a 59.7% e) 59.7% a 40.3% A solution of 130.6 mL of concentrated 14an is added to 101.? mL of a solution of AgNO; of unknown concentration, and 3.7661 g of a yellow powder precipitates out of solution. What was the original concentration of AgN03? (Molar Masses - Na+: 22.99 gr’mol, P0437 94.97 glmol, Agl: 102.87 gimol, N03": 62.01 g/mol.) a) 0.6504 M b) 0.02949 M c) 0.206? M cl) 0.08847 M e) 0.2654 M . . ’K '1. 7-. t, up.) i I ..i".’]'.’ You add 51.9 g of a hot Mo metal (Specific Heat Capacity = 0.2513 .l/K-g) to 118.0 mi. of water at 203°C in a very insulating calorimeter. By the time you measure the final temperature of 228°C for the combined waterfMo solution, you realize that you forgot to measure the initial temperature of the metal. Assuming ilié'Eaterimete-r' constant (Cc) is zero, and knowing the Specific—Heat Capacity of water is 4.18 .lz’K-g, what was the initial temperature ofthe 46.2 g ofMo metal? b) 432°C 0) 100.0°C cl) 273°C c) 619°C ‘_,-",1 ti {7 LI"- '. it ', ‘-.— P]; 1 .J #91 Jul _. Two-Parr uestions.‘ Two-Part Question A: mH : 13.4 61 a] 10) Part 1 (3 points) - A 134.9 g sample of an unknown metal, at 100.0”C, is placed in 175 mL of water, in a perfect calorimeter, that is at 202°C (before the addition of the metal). Once equilibrium is reached, the water and the metal are at 244°C. If the Specific Heat Capacity of Water is 4.18 JKK-g, what is the Specific Heat Capacity of this unknown metal? '1 '.kT-if- 4;. l") t 2 1‘15- (3 “it ""1 4 a) 1.45 J/K-g (B) 51;”) "0.301 .vK-g (Sr) 0) 0.379 Jr‘K-g (Rb) .4 3,. d) 0.223 J/K-g (Sn) 1:) 1.13 J/K-g (N) (l'iin/l lft\1l’“’l'4'i‘r" 3‘) 2-651?" I ‘ “M Q [G Nitfl'q‘hl'ljl’art Ii (5 points) - An unknown mass ofthis metal, heated to 184.00C, is placed in a #73 'l’ perfect calorimeter containing 26.8 g of ice (at 000°C). This completely converts all of the ice to water - the final equilibrium temperature of the water and the metal is 343°C. If the Specific Heat Capacity of Water is 4.18 .IfK-g, and the Heat of TH.“ <6, I I ' i Q l O Fusmn of water is 6.00? Miami, and the Specrfic Heat of the metal 15 the value determined in 10) above, what is the original mass of this metal? - - A 7 a) 199 g b) 377g 0) 235 g d) 3.67 kg @3865 g gilt-"~- '-'-'</-‘ “"1714? r' v- 1,1309%» 14a .73 *" C. B Two-Part Question B: 12) Part I (2 points) - A basic solution of Ba(OH)2 was standardized versus 0.8506 g of I ‘I . ;_;1_<-__:;Cgfl 5,14? KHP (potassium hydrogen phthalatc) acid - the volume of Ba(OI-I)2 required to [ti-:11 WL "Who. )3 fully neutralize this mass of KHP was 15.38 mL. What is the standardized moiarity ' " of the Ba(OI-l)g solution? _ U1. L823. H r __ _ I (Molar masses-1‘3: 39.10 gimol, Hydrogen Phthalate‘: 165.12 gfmol, W i P ' =’ ' Ba2+: 13?.33 grmol,01-r: 17.01 g/mol.) 0.39.2.1, a) 0.54I6M b) 0.1614M c) 0.2?08M d) 0.002083M e) 0.1354M Vi" ' ‘3— ’; r '3' '. '— _'_" J {‘2 (J . cit-‘38 I“ "11-h '. t‘ _,..,fii'1\“")\ 13) Part II (5 points) - Once standardized, a total of 18.66 mL of the Ba(OH)2 standard solution from 12) was required to totally react with 0.4756 g of an unknown dz'protr'c acid. Based on your calculations, the Molar Mass of the unknown acid appears to be closest to which of the following? i).- ‘(_\_.ll a) Riboflavin (376.37 gtmol) b) Azeiaic Acid (188.22 gr’mol) " d) Lactic Acid, Lithium Salt d) Cyclopentane-Dicarboxylic Acid (96.01 g/mol) (158.15 g/rnol) e) Methanediol (48.04 gfmol) Periodic Table of the Elements 1 2 3 4 5 6 7 8 9 1D '11 12 13 14 15 16 17 18 nyamcm 1 H He 10025-1 7 1.002502 '2 lid hiunn Mfllum earl-Inn! name Wan cnmum nllmgen on man llumns neon ammlc number 5 6 7 a 9 1 0 6.5412 9.012133 3 1951' Elch hl main rnEIllua mus 10.11111r 12.0101I 3 111.0087! 15.0091 3 1669610129 20.170? 0 22.989770 2 26.30 I 0 Damian!!! calcium :Iurninm Mn phosphorus “in: chlalna mean 1 3 1 4 1 5 1 6 1? 1 H Al SI P 3 Cl Ar 26.351535 2 23.08 5' II 30.9?3701 2 _ 32.066 6 35 “THE 39.018 1 tcandwm litanium «new chromium manganese Iran :01)!“ metal coupe! um: gllhum 991mm anonl: titanium bra-Hm. kryplun 23 26 27 25 29 .30 31 32 33 3:1 35 36 Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br r “35591 U 47.867 1 50.9111 1 51.9901 0 51333004 El SENS 2 53.540 3 5&3? 2! 59.72:! I 72.51 2 YI.92160 2 23.90 31 79 90-1” 0100 l anfln’my talluflum Incline xenon 39.0933 1 10.073 711 126.9044? 3 wall“: mum At Rn I201”?! 222.017 127.50 3 nmiurn maimerlum ununnifium umjnunium I umwm 1GB 09 1 10 1 1 1 1 1 2 H5 t Uun Uuu Uub i; I 11 08.1 0 272.140 272.1535 271' Mmaflum 21.110010?“ “50(11an IBM!“ OWGIHIT‘ mlrruum WU?" mullLlTl film *Ianthanoids ‘50:!0 3 15]. 1 157.25 151925311 2 182.50 :1 167133032 2 161.26 3 "58.93421 1210 J} mmium ammwu wrkam Mullum wlnrnm muck-nun- fannlun manque-vi nounl'xum 94 95 95 9? 93 99 100 101 102 Pu Am Cm Bk Cf Es Fm Md No 2-34.01“? 43.0611 47.0703 24mm; 25anfi 52.0330 57.0951 50.0966 259.1011 *‘actinoids R = 8.31451 .UK-mol R = 0.082057 L-atmfmol-K 1 Ci = 3.70 x 10m Bq I Bq = 1 evenusec 1 cal = 4.184 J 1L aim = 101.325 J l atm=76010n‘=101.325 kPa l J: l kg-rnzfsec2 1P0= l kg/rn-sec2 1CV=1J F=9.64853 x 104061616 97: 3.2898 x 1015Hz(Rydberg) 1mu=1.6605x10—” kg=931.494 MeV c = 2.998 x103 W500 I: = 6.626 x 10-3” J-sec 1 Mev = 1.6022 x 10*” J Elementary charge (.9) = 1.60218 x 10*19 c 6n = 1.008664% 11; {p = 100727647 u; 36 or fife = 5.485799 7; 10-4 u ‘H = 100782505 11 “He = 4.0026 1.1 When in doubt, remember that the answer is always 42, or 11:. Never forget that! SCRATCH PAPER . u. 1 .fHI ...
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chem 6BL old test - SCORE: Chemistry 6BL EXAM #1 FORM B...

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