exam_1_spring_2005

exam_1_spring_2005 - Chem 105a Exam 1 Prim Name Last First...

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Unformatted text preview: Chem 105a Exam 1 Prim Name Last, First Tuesday, February 8, 2005 Last 3 digits Soc Sec. # Professor Philip Stephens TA's Name Major I? Please Sign Below: I certify that l have observed all the rules of Academic Integrity while taking this examination. Si gnature: INSTRUCTIONS 1. There are 11 questions on 11 pages. Please count them before you begin. 2. You must Show your work to receive full credit (except for multiple choice questions). 3. If necessary. please continue your solutions on the back of the preceding page (facing you). 4. DO NOT use pencil. Exam 1 1. (5 pts.) What are the names of the following elements? a) Cu CQWer b) Sb OKVlmovw') c) W d) Cs C! SlUM e) Ge %Q(w\o\v~\\1w~ 7 2. (0 pts.) What are the formulae of the following compounds? a) potassium chromate K 2 Cr Q.+ b) propane C3“3 c) ammonia Pr N Z d) carbon monoxide e) ethanol f) iron (lll) oxide (rust) g) phosphoric acid 3. (fits) A diamond contains 5.0 x 1021 atoms of carbon. 5 a) How many moles of carbon are in this diamond? 7. 3 \ MQAQ, Chm: = (3.BZZ.><\Q 0313wa Z\ —- 2‘ Sovuq akwd = 543"“3 Mg“ ai—mj 7.3 Gu22¥\o : \Q b) How many grams of carbon are in this diamond? Acvmk“ C = \zxn “#5 \Z.Q\ 3 -3 . 830 N de4 Lab“: 5k -—3 ‘3 30746 X‘Z O\ 4. qlpts.) Juglone is a natural herbicide found in black walnuts. lts formula is ClOH6O3. 2 a) Calculate the molar mass ofjuglone. MR: CD at \7..c>\) «Ir (kgysheui) +Q~A Km) Wan—— -— WM W q b) Calculate the mass percentage of the elements C, H and O in juglone. ‘ w¢\£ 3Vj\we wuku \7‘4-J 3 \WJLL Pym («Rhea N may, CM‘DN W11. Wu \QXVLM - \Lu.\ 5 UbuigL Mk Lofil~608 -.- QQK-gs \wJLn. COKE“?! ’3 «4H,: Oahu: Wu. ML 3X\ka.u = L(—85,. q 70 Mm C. " L411 X\QQ: Q l7w-Ql 7Q ‘23 M53 Pr = “mm” Mm; 332; H- 5. pts.) The compound adrenaline contains 56.79% C, 6.56% H, 28.37% 0 and 8.28% N by mass. What is the empirical formula of adrenaline? lQQa GLQTQWMLO; Caulk“... 5,6795 C = 31°79 wdua C = 4-73wunog 28775 o ‘ 2337 Juno .- I77 who No a? 22 3 N = 813 “MM: 053 we. Nor 6. (6pm.) Balance the following reactions: 2 P+ a) NaHCO3(s) heat Na2C03(s) + C02(g) + H20(g) (production of C02 from baking soda) 01 Nu\-\(o3 a Nazca, *‘ R32 ‘“ H20 Cf207(3) heat Cr203(5) + + (ammonium dichromate volcano reaction) a CfZQS +- NZ"’ c) CaCz + H20 —> C2H2 + Ca(OH)2 (basis of acetylene lamp street lighting) CQCL +-Z_HLQ —-> CL“; ‘l- (C(W)L 7 dlpts.) The thermite reaction has been used for welding railroad rails. It is Fe203(s) + Al(s) -> Fe(l) + AI203(s) + heat T molten iron 4} / I 32% + 2M _> sure. + mac? 3 a) What mass of Fe203 must be used to produce 15g iron? igfi Fe, = E “dun R = 0.2Bfi MM R 5'3; on 3’ MIL». Q26; = 033' * [CZH’Y-a’f) *- (“N-u)? = éaLb é Ré o? b) What mass of A] must . . \Mm A\—-—> \ “MR. 0.269% mm IM —_9 0.2.64 was. R (3.7.“ MM M = Q.ZQ\ *Zgfie = 7.2g3 A-\ c) How many grams of A1203 are produced in a reaction giving 15g iron? 0.2 Mus R “ '~ fiche“: om’ mm N163 = on“ 2 ,< 26.9? + 3 x\\o.u 1 x... — Aw 8. (quts) Hydrogen cyanide is produced industrially from the reaction of gaseous NH}, 02 and CH4: NH3(g) + 02(8) + CH4(g) -* HCN(8) + H20(8) a) If 5.00 x l03 kg each of NH3, 02 and CH4 are reacted, which is the limiting reactant? ell/H3 + 30; + 20m ———7 2,\+cw +C'3H'ZQ ' 6 §X\Q3kj = 5 :3 *‘0 wgqu Dwou- 3*\\u08) N“? r " 3 4? uxmzkg Q; = 3"“ = 0431. HQ will»: Oz links o 5 Am ‘Lj CM-q. = 33‘\\3 .: Q_3\2'x\u Dam + LL*\~®9] MW 0A4. 5:97“ b) What mass of HCN will be produced? _., Z NEAL WKN 5» a H- ' WM (N ma own, Wins 0; -—-> Q'hg “Q *"'T 3 Mat Q; 9. (8pm.) + a) Calculate the molarity of a solution made by dissolving 22.5 g of ammonium sulfate in water; the volume of the solution is 74.0 mL. (MM)LSQ\‘, ‘- MM: lewni 4— 87mm? + 32.x37 3? urvk\\o.u :: I32.Z ma m.»st = 22-°’/c32.z=0-‘70 W ' . .l D - , \S O _3 = 52.30 M 7mg) K \Q b) What is the molarity of ammonium ions in this solution? + .. (memoir —> 2 W + 3°» Mdtmth q, NH: Vs 4.60M c) What is the molarity of sulfate ions in this solution? Zu- . Mmctr'tl-c‘ at}. 50». ‘5 02130M — ' "7 10 10. (12 pts.) When the following solutions are mixed together, what precipitate (if any) will form? In cases where precipitation occurs, write a balanced equation and a balanced net ionic equation for the reaction. 8) F8504 (uq) + KCHGCI) R01 5’leth . “O kzgow IolJLfi; V‘O TX“. 3.9+” b) Al(NO3)3(aq) + NH4OH(aq) Aim} mm“ Mandi (NNMOJ, mum A‘3‘\’+ 30H ' ma Allmkk 3’91" 0) CaCl2(aq) + NaZSO4(aq) ' Carat, iCtolx/blt' moat NaUL Julfbkn, Na. Qquza. quio... —-9 “5°4- 5; *' Z Q Ca” + 5o“r ' -—> Cowhb d) 195(an + Ni(NO3)2 (aq) km; Scnd‘vh. ..' Nzr L N§S “Auk/lab. KLS‘ l- NCCN‘DJ)L —> NJ 1, » ZKWZ $2- +N.\&+ "a \Vfg J, ll 11. (8pm.) What mass of sodium phosphate is required to precipitate all of the Pb2+ ions from 150 mL of 0.250 M lead nitrate solution? 2 NQKPOW + 3 (W:)L ——> 955%th XI + 6N“N03 fl 3 MM (Now/03)), m met w'xi-e~ ‘ 37~3’X\0'3 *3; MM NQ?PLM,_ NLvam\ . _ 3 = 3319 ,( [3xzzqq +3ofij7 +er\\a.o3 = 4Q‘t‘i 3 '-"- 4.0qc1 \43 Nu3€0¢ .__ p.-. —_'.———».--,—~w WW...” —« w — ...
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exam_1_spring_2005 - Chem 105a Exam 1 Prim Name Last First...

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