Ch115_T1C_F06_Key - Page 1 of 5 Name Key Student Number...

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Unformatted text preview: Page 1 of 5 Name Key Student Number (Please Print) Chem 115 — Section 1 Hour Examination I October 13, 2006 This test consists of five (5) pages, including this cover page. Be sure your copy is complete before beginning your work. If this test packet is defective, ask for another one. A copy of the periodic table will be distributed with this test. DO NOT WRITE BELOW THIS LIN E TOTAL Robert. L. Carter, PL]? 6 2310 ocw.umb.edu Page 2 of 5 Name K a? 1. (10 points; 2 points each) Who did what? Match the person with the concept or discovery. '1’ People Becquerel Chadwick Dalton Davy Lavoisier Mendeleev Millikan Moseley Nagaoka Proust Thomson Rutherford Concepts and Discoveries a. L—ZLU 01‘; 1 fig Father of quantitative chemistry b. Thomson 0. M 1. '1) 'r g mg Determined the charge of the electron d. M0 ‘06. id}; Determined atomic numbers, basis of modern periodic table Rw’ibflurilori. Proposed “plum pudding” model of the atom e. Proved that atoms have a positive nucleus and distant electrons 2. (8 points; 4 points each) Give answers to the following items, which refer to C 5H4O3 (mw. = 112.08 11). NA = 6.022 x 1023; at. wt. C = 12.01, H = 1.008, O= 16.00 u. (0.3er )5 let 42.K%% O atoms in 0.4325 g of C5H4O3 weight percent 0 in C5H403 3. (12 points; 6 points each) In the spaces provided, balance the following skeletal equations, using lowest whole number coeflicients. a. Au(NO3)3 + Hg p All + Hg(N03)2 ZAULCN03>3 4r 3 H3——B- 2AM: ‘\" Bchl‘MQB); b- C5H403 + 02 e ? (combustion) (in: be:C)%, fi— 2:6): ~—-¥' Q; (LC) L -¥' 2-bk2fCD =37 20.5mm; do, we 100.0,, + 4w.ch Robert L. Carter, Ph.D @ 2010 ocw.umb.edu Page 3 of 5 Name K€¥ 4. (36 points; 6 points each part) Fill in the blanks with the correct answers. T a. Name the following compounds, using I.U.P.A.C. rules of nomenclature. Co(Hzl:'O4)2 (foloulitu) d='\lr_'\>fdr0€dn Ehoépln'zic HC103 lemr ‘l g any at b. Give formulas for the following. ammonium dichrornate l NR“): Q1“; 0} tetraphosphorus hexoxide g; 0‘ 0. Indicate the number of protons (p), neutrons (n), and electrons (e). Fit; n: p= $5 TrsAs atom e ” 5t"1362+ ion p= 2.6: d. Give the symbol and name of the following elements: M? in; 6. Indicate whether each of the following compounds is ionic or molecular. NO maleawlxr 3rd period alkaline earth symbol transition element with Z = 26 symbol name it 1" o m A1013 " 0 RC. f. Answer the following: (1.530 + 9.5762) (i) The answer to the problem should have 5 significant figures. 0-245093 (ii) For each element, give the expected charge when it forms a monatomic ion: Ba 1+ Br \— (or gum-t -—3 (iii) Which one of the following elements forms ionic compounds in which its monatomic ion might have one of two or more possible charges: Al, I, Pb, Ba, Cs? name Ma? meal um Answer i Robert L. Carter, Ph.D G 2010 ocw.umb.edu Page 4 of 5 7 Name \5 a? 5- (16 points) Answer both parts. Show work in the spaces provided to justify your answers. a. (12 points) A compound contains 90.505 % carbon and 9.495 % hydrogen. What is the empirical formula of this compound? (at. wts.: C = 12.01 u, H = 1.008 11) Rééwmc 05:10.05)?S GQWQM. Me '1: analog. 6 =91 -—-> 4 W11: (arwl‘gfi P” w\‘ 1:. 61.0th Marl. H I (j l ItDE><323 kl ) (D M C= (aoxogaefmc >-;. 1,55% We (3 33> 1.15 =>§ 04% b. (4 points) If the molecular weight of the compound is 106.16 u, what is its molecular formula? 1%. w. (3.4%; =- 8%,OK vww. 21.00.11; :2 :5 QSH‘D «9.1.5. gaofa Robert L. Carter, Ph.D © 2010 ocw.umb.edu Page 5 of 5 7 NamevKafi¢____—_ 6. (18 points + 5 points bonus) The BIZHRZ“ ion is a cage—like structure of twelve boron atoms. The sodium salt of this anion can be prepared by the following reaction: 2 + 5 B2H6 _' NaQBlelz + H2 How many grams of H2 gas will be produced when NaQBlzI-I12 is synthesized in the reaction of 0.250 g NaIBH4 and 0.420 g BZI-Ifi? You must identify the limiting reagent, based on appropriate calculations. Show work in the spaces provided to justify your answers. [f.w. NaBH4 = 37.83 11; m.w. BEE-I6 = 27.67 u; f.w. NaZBIZH12 = 187.8 11; m.w. I-I2 = 2.016 11.] We mace“:(0.1soanmEHg(v/dm3“s )7: 0,009Caoggwqe "bq.‘3308N7LV’bHI-f 0,006Gogg/2 -.-. 0,0033045 MBLHb‘(O.‘+LO%B>H-Q<MBI)¥9 ):O,D\S-lwbwre 2:¥JéD:}J% fiszJfi1p 0,591le [g '3 9,0030%“ $8)“; h M": +5 59‘2" (o‘olSlWM6L“e\(l%WQ H3- \ (LOW; Hg)" 3 23'" was 8136, 1:: O. OMS'bkla-KL “5 0,0145% LL.) BONUS (5 points) How many grams of the reactant that is not the limiting reagent will be lefi over after the reacion is complete? mes M.st =. (0.0151 MAB»; 2. Muswfi Patagonian % Li M b) Muir-Bag = 8122‘!“t goat:le - 0.23029253Hq fiNmBHLrtel-‘Jr: 03503-01303 :1 0,0L03 Robert L. Carter, Ph.D © 2010 ocw.umb.edu ...
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This note was uploaded on 03/01/2012 for the course CHEM 116 taught by Professor Robertcarter during the Spring '07 term at University of Massachusetts Boston.

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Ch115_T1C_F06_Key - Page 1 of 5 Name Key Student Number...

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