Practice Exam 2 Key

Practice Exam 2 Key - key Lab Sec. # ; ; Lab day/time:...

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Unformatted text preview: key Lab Sec. # ; ; Lab day/time: Andreas Toupadakis, Ph.D. Winter 2006 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 (20 problems, 8 pages). (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 # 10—15 (6 points each) # 16-20 Total Score (100) (4 points each) I 0-15 total points: (28 points) / 28 / 100 WINTER 2006 MIDERM 1 (Page 2 of 8) Part 1: Multiple Choice, Concepts (4 points each) Select the best answer (one answer) and enter your choice on the cover sheet — No partial credit 1. The mass of any atom is almost exclusively located in the nucleus of the atom. A matchbox filled with the same material as the nuclei of atoms are made of would weigh about: a. 2.5 milligrams b. 2.5 kilograms c. 2.5 tons d. 2.5 million tons —> e. 2.5 billion tons 2. Choose the correct statement. a. Neutrons have no charge and no mass —% b. An electron has 1/1837 the mass ofa proton The atomic number is the total number of protons and neutrons in the nucleus c. d. The charge of a proton is 1837 times the charge of an electron e. Electrons and protons have about the same mass 3. Which ofthe following statements is true concerning the masses of individual Cl atoms? a. All atoms have a mass of35.45 u ———> b. None ofthe atoms have a mass of35.45 u c. Some ofthe atoms have a mass of35.45 u d. Most of the atoms have a mass of35.45 u e. All atoms have a mass of 17 u 4. In which compound does carbon have an oxidation state of zero? a. C2H2 ———> b. cuzo c. CH3OH d. NagCO3 e. C02 5. Choose the INCORRECT formula/name combination. a. Fe2(SO4)3 iron(IIl) sulfate b. HBrO3 bromic acid l PC15 phosphorus chloride 9- SCl4 sulfur tetrachloride e. Sr(IO3)2 strontium iodate WINTER 2006 MIDERM 1 (Page 3 of 8) 6. Choose the correct name for the following organic structure. CH3CH2CHBrCH2CH3 v? a. 3-brom0pentane b. 3-bromopropane c. l-bromo—l -ethylpropane d. pentane e. pentylbromide 7. For the reaction symbolized as HCl(aq) + NaOH(aq) —> NaCl(aq) + H200) water is both: a. a reactant and the solute b. a reactant and the solvent c. a product and the solute -——> d. a product and the solvent e. a liquid and the intermediate 8. When the equation C82 + C12 —+ CCl4 + SzClz is balanced with the smallest integer coefficients, the sum of the coefficients is: a. ———> b. .0 5 6 4 3 7 9. Choose the INCORRECT statement: a. A limiting reactant is completely consumed in a reaction. b. The theoretical yield of a reaction is the quantity of product calculated to form when all of the limiting reagent reacts. c. The percent yield compares the actual and theoretical yields. d. A mole of any substance is Avogadro’s number (6.02xl 023) of formula units of that substance. .9 e. A balanced chemical equation shows unequal numbers of atoms of each element on each side of the equation. WINTER 2006 MIDERM l (Page 4 of 8) Part 11: Multiple Choice, Short Calculations (6 points each) Select the best answer (one answer) and enter your choice on the cover sheet —- No partial credit 10. An ion has 45 neutrons and 36 electrons. If it is an anion with a —l charge, which is its correct symbol? 45 — 80 — 90 — 81 — 80 — NQUlVOé glow \Aas 36-l : 3g egechmvfl go 3.5 P‘rOl'OV‘g 35 onlovxs P-B 8v , A :‘L+N :3€+ Lié : 80 11. Which ofthe following contains the greatest number of atoms? a. lmole ong molecules b. 2 moles of P4 molecules c. 4 moles of chlorine molecules d. 8moles ofH atoms ———> e. all of these contain the same number of atoms 1 mega §3 lAOL§ 8 Woe“ of §o€4€w u\—ow\9. 1 woées PL. Move 8 wo€ec o’li plaosPl/mvw; atoms. L‘ Ce; H 8 II 1| 8 woag H oiowfi 12. Given the reaction: 2KMnO4+10Kl+8H2804—>6K2804+2MnSO4+512+8H20 How many moles of K2804 are produced by allowing five moles each of KMnO4, KI and H2504 to react? #9 a' 3mm Moe kigoq 6 woe k1§0q 6 woé er'LgOLl b. lmol c. 2mol Q. woe kaOL‘ l0 “We KI— 8 “mg ngo d. 4mol e. Smol Game MCOL: , is woe kt§0q (a M tan/mot.) W « i Q We! lfiMi/‘Oq w 1‘ S0 . w Mir—We w % w w l0 woe lrcl (g “We HLQOq) G “We “‘(O‘I > : 73.73 \Mo? #1909 8 Woe l’nSOq ——- q WINTER 2006 MIDERM 1 (Page 5 of 8) 13. How many mL of 0.024 M solution can be produced from 14.1 mL of3.0 M solution? a. (14.1)(0.024)(3.0) b. 14.1(o.024/3.0) (X \M L\<O~OZL\ M) 3 (10.1 mg (3.0 Ml ~—9 c. 14.1(3.0/0.024) d. (14.1/0.024)/3.0 3 .0 e. noneofthese X :Ol'l‘l) ()qu ) 14. How many moles of H3PO4 are produced when 20.0 g of HCl are produced by the reaction PC15 + 4 H20 —> H3PO4 + 5 HCl? (P = 31.0, C1 = 35.5, H = 1.0, O = 16.0 g/mol) a. (ZOO/36.5) * p0 b. (20.0/35.5)/5 1 W06 HW’OH O M Y ——9c. (20.0/36.5)/5 S W°€ Ha 93,65 3 MC? (1. (ZOO/98.0) e. (20.0/98.0)/5 20 . O (x163 \w0‘( . a .2 was mm. =( >100 3 H 9X36$ 7) HQ? 15. A hypothetical element E has two stable isotopes: 13-46 = 46.046 u 64.08% and 13-51 = 50.826 u 35.92% What is the average atom weight of the element? > a. 47.76u bi L16.OL‘6X 0-6q08 + €0.816xo350n : c. . u d. 48.50u e. 47.44u : 10391 (A +1616 (,L : : Q4411— u WINTER 2006 MIDERM 1 (Page 6 of 8) Part III: (28 points) Please show all work for calculations — Partial credit may be given 16. A block of lead weighs 11.35 g. How many atoms are in the block? €95 (“3539‘03 < [woé Plo 6.012x iota-ileum} : 101.13 Pb lwor No ’L. ' 3.29% mm MW; 0% pt) C 17. The metal M forms the chloride MCl4 containing 75.0% C1 by weight. M 9 What is the molar mass of M? NW1. 0* WHE‘l'ove AA : X g/mg MW " M0“: = (m gags) :(X+lqz.\ 3 /wfi 1<.o M2. ’00 x+iqg_ A13 H 18. Maprotiline, a tetracyclic drug prescribed for the treatment of depression, has the following mass é) composition: C 86.59%, H 8.35%, N 5.05%. Find the empirical formula ofmaprotiline. Cease H 8.35 N $.05 C 86.59 H 5’35 cog l1.0\ l'Ol Iq.oo WINTER 2006 MIDERM 1 19. How many moles of HCl are in 300.0 mL of 12.0 M solution? 1 9% > \N\O’€ Ha : (0.3000 L>< ‘2': :06 Ha In the following reaction: 2 KClO3(s) —+ 2 KCl(s) + 3 02(g) 14.0 g KClO3 yielded 1.40 g KC]. What is the percent yield? (V2394 (1:955 0:!6-0 /wo£l ) ) (a Q?“ 20. uclvu—e (bl +M€OY€+ Mug (3) % jifapd :, x (007° OCluo—Q Z l-Lio a KCQ (Page 7 of 8) ‘l’lAQOY-e‘l'flogt (“to Bkdogwl twee! k003><22______ WINTER 2006 MIDERM 1 (Page 8 of 8) Periodic Table l I 1 1.00114 3 . ‘ 8 , I ' ( A ' . , ‘74 159%: 1a * i7 ' V C1 ; ' 15.4527 . .N I 35 B” 12 ' - if“ ' Mg P S 24,3053 30.973571“ 31056 W 21 21 23 24 25 ‘ 2‘3 v 12 . TM . ix V ' Sc 11 V Cr Mn . Cu ’ 11 Ge Se I ‘ 391'!in “.9599") «I ,86'.‘ 509415 .l.‘}9¢$l 5433a“ 5 i a . 63.546 _ $.39 6 w .23 719] 74. 2160 73,116 V , 3? 33 39‘ 40 «ll 41 43 M V 48 $9 5 5 52 5.1 54 ' 1 t , M I ’" r . , Rb Sr ‘1' Mr Nb iv o it. Ru l C ,n Sn S F e g I Xe mama 37,132 “90535 91:24 92.99633 95.94 (93‘ 101-07 102, . 1 2A1! nun; 1!le 121,750 £2160 11:3.«1447 13 .29 56 53' 72 73 74 76 an 31 I! a} 3.3 I 35 “IS Ba La Hf Ta W R“ 05 ' Au l-' v Tl Pb E 1' Po At Rn 07.327 1339055 173.49 IW.94'.'9 [83.34 like 07 [90.23 36655 1‘00.~ ZMJKBE 387.2 mamas (2W) » [1in {112) Ht: 75 L X! ‘t Bh 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. - 23 . NA — 6. 022x 10 % Yield = Actual Yield (particles per mole) L Theoretical Yield ...
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Practice Exam 2 Key - key Lab Sec. # ; ; Lab day/time:...

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