exam1 key w07

exam1 key w07 - © ké‘l ' First Name Last Name Lab Sec....

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Unformatted text preview: © ké‘l ' First Name Last Name Lab Sec. # ; TA: ; Lab day/time: Andreas Toupadakis, Ph.D. Winter 2007 CHEMISTRY 2A Section B EXAM 1 Multiple Choice (circle one) Instructions: CLOSED BOOK EXAM! No books, notes, or additional scrap paper are permitted. All information required is contained on the exam. Place all work in the space provided. If you require additional space, use the back of the exam. A scientific calculator may be used (if it is a programmable calculator, its memory must be cleared before the exam). (1) Read each question carefully. (2) For Parts I and 11, there is no partial credit given and only answers marked on this cover page will be graded. (3) The last page contains a periodic table and some useful information. You may remove it for easy access. (4) If you finish early, RECHECK YOUR ANSWERS! U.C. Davis is an Honor Institution Possible Points # 1~9 (4 points each) # 10-15 (6 points each) Name KEY EXAM 1 (Page 2 of 8) _____________________,_________.___—_—————-—————-—- Part 1: Multiple Choice, Concepts (4 points each) Select the best answer and enter your choice on the cover sheet — No partial credit 1. Which of the following would not be affected by an electric field? a. Alpha particles b. Beta particles 0. Gamma rays d. protons e. electrons 2. The total numbers of neutrons, protons, and electrons in 35C1' are: a. 17 neutrons, 35 protons, 36 electrons b. 35 neutrons, 17 protons, 18 electrons c. 18 neutrons, 17 protons, 16 electrons d. 18 neutrons, 17 protons, 18 electrons e. 17 neutrons, 17 protons, l7 electrons 3. Which is the more abundant isotope, C1-35 or Cl-37? a. the two isotopes are equal in abundance b. Cl-37 c. Cl—35 d. a third unstable isotope is more abundant e. Cl-17 4. Choose the INCORRECT statement. a. A molecule is a group of bonded atoms that exist as an entity. b. Ionic compounds result from combinations of metals and nonmetals. c. An anion is a positive ion. d. The empirical formula is the simplest formula of the ratio of atoms. e. The molecular formula is the listing of the atoms in an actual molecule. 5. Choose the INCORRECT name formula combination. a. CaH2 calcium hydroxide b. SiOz silicon dioxide c. HClO hypochlorous acid 9- Cu3(PO4)2 copper (II) phosphate e. AlCl3 aluminum chloride Name KEY EXAM 1 (Page 3 of 8) _____________________________________..__.—————————————-—- 6. Choose the correct name for the following organic structure. CH3CH2CH3 a. pentane b. propane c. 2-methylbutane d. l ,3 -dimethylpropane e. 2-ethylpropane 7. When the chemical equation Fe2(C204)3 ———> FeC204 + C02 is balanced with the SMALLEST INTEGER coefficients, the coefficient of C02 is: a. b. c. d. e. l UIUJ-BN 8. Choose the INCORRECT statement. A chemical equation is a shorthand way of representing a chemical reaction. a. b. Calculations of the amounts of reactants used or products formed are called stoichiometry. c. The numbers in front of formulas in balanced equations are called stoichiometric coefficients. d. Molarity is defined as moles of solute per kg of solution. e. The solvent determines the physical state of the solution. 9. What is the sum of the smallest-integer coefficients in the balanced equation that represents the complete combustion of the relatively new gasoline additive "MTBE," for which the molecular formula is C5H120? a. 39 b. 37 c. 29 d. 24 20 Name KEY EXAM l (Page 4 of 8) Part 11: Multiple Choice, Short Calculations (6 points each) Select the best answer and enter your choice on the cover sheet — N0 partial credit 10. The following ratios of masses were obtained with a mass spectrometer: . 3'5 1375a 13F Ca€€z (e :x cm . ———=1.8406 and ———=1.5832 w ' 19F 12C 9 6 to) [7— 35 v , » _ What is the mass in atomic mass units ofa 17 Cl atom? gv “ j 0W“ , 6C ’ Z 0”” a. 35.45amu b. 36.36amu Need 10 {mo x'. C~ 13-952mm Bot 3L; 1.9q06 «r‘ 3 1 1883’). wofliper €619 d. 35.00amu y 7, e. 34.97amu ; Hal—\OG' L58 3?, % X:Cl9_0wU\(l.8q06-L§6’31 2‘” 11. How many moles of lead are present in a piece of lead with a volume of 0.600 cm3? The density of Pb is 11.34 g/cm3. a. 6.80 if (1)9328 <0. 600 W‘Xihifl.) 1: 6.80 3 Pk» d. 0.547 I ew" 6. 0.0912 . (6.90 «3 MOM 9‘0 : 0.0m 9.01.7. '3 (>10 12. The correct number of atoms in 10.0 g of CaC03 (100.0 g/mol) is: a. 18.1x1022 b. 30.1x1022 c. 6.02x1022 d. 12.1x1023 e. 12.1x1022 11 (10.0 6CQ(O;) twee COCO; <5 Woe QitowS )<G.OZ’L>« to atom) loo~0 ACOCOE fl wo€ COCO} \ woe o¥ow§ A . 13 : $.01 X10 O.\’OW§ ‘21 XO‘i X \011 O‘x‘ouAQ. Name KEY EXAM 1 (Page 5 of 8) 13. Mesitylene, a hydrocarbon that occurs in small amounts in crude oil, has an empirical formula of C3H4. The experimentally determined molecular mass of this substance is 121 amu. What is the molecular formula of mesit lene? .- y (CBPU-Ux )X"\Z)%)"‘ a. C3H4 b. CH . c. CSH: Mo‘gg \OOS€$ OV\ pr‘xvxco-Q "gokufia ‘2 d. $12216 301.0 omu\ ‘K' utm Wit; v. douo 0M) 6- 15 20 /\/\O§< bowel om vmo€€CU€uv ’QOYwuaejl : \2i owu ‘1\0W‘UL :2131‘ woS‘r lofi lVfifaer SO X:3 L\O OWL) ) X : 14. How many grams of N2 are required to react with 2.30 moles of Mg in the process? 3 Mg + N2 ——> Mg3N2 (Mg = 24.3 g/mol, N = 14.0 g/mol) (2.30/3)(28.0) (2.30/3) ( (2.30)(28.0) Q30 we! M3)[M <2 9'0 A N L g Mme 1 MAO-E N7, 999-9 (2.30/3)/28.0 (2.30)(3)(28.0) .0 15. What is the molarity of sucrose (C12H22011) if 110.0 g of a 92% pure solid is dissolved per 250.0 mL of water solution? a. 0.296M b. 1.29M > c. 0.321M CG’éCugoiC {WM- (CH’RWOJ: an, i d. 1.40M me e. 1.18M (“0.0 ‘2) (\wpuvc Sucmy<g1 QPOYC g‘oc. I >’ 1005 lwvaflgvg 3 PUYfi Cuc. V 20.1% We Pave, CuH‘LzOh. mogovk ' 0.1036 Luca; éowosc ’ \‘\Q My. ‘ M) ‘ Gigoo L<o€ui\ow Name KEY EXAM 1 (Page 6 0f 8) Part III: Long Answers (28 points) Please show all work for calculations — Partial credit may be given 16. Calculate the molarity of a solution made by dissolving 23.4 g of sodium sulfate (N aZSO4) in enough water to form 125 mL of solution. pi” a) Moles of Na2804: i Woe NOLCOH _. L‘- p’c b) Liters of solution: 6 1L .,_ 016 m ) mm L‘ Pi: c) Molarity of solution: W -; \31 “we Nam“ Ollg L Seen 4. Lgoem Name KEY EXAM l (Page 7 of 8) ____________—________________.___._.————-——-————— 17. Carbon tetrachloride (CC14) was prepared by reacting 100. g of carbon disulfide and 100. g of chlorine. Calculate the percent yield if 65.0 g of CCl4 was obtained from the reaction: C82 + 3012 —> cc14 + 32012 8 Pk a) Grams of CCl4 that can be formed from each reactant: ‘00. Cgl lung-Q C§L .X\W°€<Ceq/XS3‘QQCCQL‘> ( 3 TCGASQCCz we cg \We (ca 1012) (“‘9 Q00. 8 woe (£1, wo€ a C0614) 1O-905CQ1 guano—6&1, \wme (09“ L‘ w: b) Limiting reactant is: Because: /€ 8 The theoretical yield is: Li Pt c) Percent yield: D€YC€W‘\’ \Iie’ed : x (000/0 12,?) a 0/0 Name KEY EXAM 1 (Page 8 of 8) Periodic Table I 2 H He 1mm 4.002802 5 6 7 8 9 If) B C N O F Ne 10L!“ mom 14,0067»! 15.999! 8.998411] 201797 I )2 l3 I4 I5 l6 I7 18 Na Mg Al SI P S Cl Ar 22.939770 243050 I I I I I _ 26.981533 amass 30.973751 31066 354527 399:: l? 2‘0 g] ‘22. 8 ’ 3’] 32 3‘3 3‘ 15 36 l\ Ca be T1 V Ga Ge As Se Br Kr 39.138] 40.073 44.955910 4?”? 50.9.15 5] .9951 54.93 I « ' - 69.72] 716] 71.9mm 75.96 79.90: 0.30 37 38 39 ‘1 4| d1 43 M 45 46 47 43 39 50 5] 52 53 54 Rb Sr Y Zr Nb 0 c Ru Rh P Ag C In S Sb Te Re 85 7461'! $7.62 8350555 91.224 92.91338 95.94 (93) “"37 10290550 1M1! 1mm 112.41! “1318 I - , [27.60 v ‘5 5 56 57 72 ’73 74 75 T6 77 78 N 80 I] (Is Ba La Hf Ta W Re OS 11' Pt 11 g T ' 13190545 [37.327 133.9055 173.39 "0.9479 “3.84 “6.21)? 1W1! 192.217 195.078 I%.96655 200 $143333 ‘ if] 88 89 “Id 105 I06 107 I08 109 "0 Ill 1‘ r Ra Ac Rf Db S Bh H5 Mt {33} (2.25} (137} WI {’52) l? l _ 1m) , (355! 13561 i _ l l { 1.00794 3 4 Li Be 6.94] 91112|fl Some useful equations and data: PLEASE NOTE: Important values and equations required for calculations are given with the respective problem. The following may or may not be of any use. Actual Yield °/ Yield = ————~——————~— 0 Theoretical Yield ...
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