exam 2 w answers

exam 2 w answers - MacDonald. C HM1020. I...

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Unformatted text preview: MacDonald. C HM1020. I "25/2008, Erma 2 Name: {A 79 9‘5 Score: '— I75 I. Circle the alkane that contains four carbon atoms? [3 pts| b. deeane c. propane d. nonane 2. Circle the substance that has a standard heat of formation (AH,»°) equal to zero? l3 ptsl a. H30(g) b. Al(g) c. (703(g) ’L- NM‘ in if! r/MJG—wi 1746'?“ 3. Circle the property that can be used to distinguish one substance from another substance? l3 ptsl a. temperature I). enthalpy d. kinetic energy 4. Circle the most oxidized organic functional group. [3 ptsl o o a. Fl-O—H b. R—c'i—OH C- Ft-CH=CH2 cl. H—c'i—H 'JI Which of the following statements is true fora given system and surroundings where q = 20 kl and w = l5 kl? Circle -‘our answer.|3 tsl ’ " 447% a a. Heat flows from the svstem to the surroundings. b. The surroundinos does work on the svstem. c. Al-J = —35 H d. A5 + Ali >0 splem surroundings 6. One mole of ionic solid will have the greatest lattice energy for which compound? (‘irclc your answer. |3 ptsl 3* 1(1- Iv- [- 20» 4- a.(‘aBr2 ) c.NaBr d.K)3() E 2 K Giaa’ 7. Which of the follow ing is true for the l'ollouing reaction? Circle your answer. I3 ptsl H:(g) + is ()3(g) —» HZOH) AH = 286 k.| a. The reaction is endothermic. b. The entltal ) ‘ of the roducts is less than that of the reactant c. Heat is absorbed by the system. d. None of the above is true. S 8. Circle the ionic compound with the lowest melting point (weakest attractive forces between the ions)? [3 ptsl a.l.iF c.Kl“ d.NaF 5 -_—. ,4 59%;, C5 1‘: 4' A’s-7377‘ [an WC! 9. Circle the organic compound that is a ketone. I3 ptsl O b. CHGCHQCHchQOH c. CHgCH=CHCH3 d. CH3CHECH2_6_OH IO. ("ircle the correct name for the following compound. [3 pts] 5- 6 CHg—CHz—gHa VANVQU‘ éoufi‘nuédf 44*5‘“ 44%;" l If 3 a. I CHa—CHg—C—CH—CH—CHg Br F CH3 a. Jehmntorll‘luoro 2-meth\ l»—l-prop\ lhc\anc h. 2~mcllt_\ |—.l-t'luoro~-l-lu'omoml—propylhexane c. 4-hromo4—ellt} l-3—l'luot‘o—2-meth} lvheptanc Ll. -l—hromo--l«eth_\l—S-l'ltIoro—(i—methylheptane No PAV Nov-K Joneq l l . For most chemical reactions carried out at a constant pressure oi~ 1 atm, energy is transferred through: [3 pts] b. work 0. light (I. heat and work [2. Circle the substance that has the highest specific heat capacity? l3 ptsl a. iron (Fe) c. gold (An) (I. copper (Cu) 13. The common name for the amino acid below is tyrosine. Following the rules for naming organic compounds, which suffix should follow the root when naming this compound? l3 ptsl 9 ii HO—C—Cli-CHQ OH NH? 21. -aminc c. —()| l4. A 0.]00 mole of (II-L1 (methane) is burned in a calorimeter (heat capacity = 783 .l/“(T). 'l‘he calorimeter contains 254 g of water (specific heat capacity = 4.l 8 .l/g-°(‘). The temperature in the calorimeter increases from 25.0 °C to 68.5 °(‘. Determine how much the heat is released when the sample of CH. reacts. l5 ptsl MacDonald. CHM/020, 1/05/2008. Exam 2 CH4(g) + 2 Ozlg) —’ 2 H200?) + (Gig) Hgaf wales—red 13 «Jaw—44¢! 5/ 7%4 ca/ow'mathv‘ + f) f4¢ Wait-w I) Héd-f' ALIBWLK'J b; flea: gag/pom)“: «flgw; 7773— . a ,4 )(685‘74— .1510 a.) :: 34049. 5" J” a.) 6/ fag Ubf‘w: any (4:: 52-45102) 3 “my. FU— fifv‘f had—fa-Jéoféé—J = -. (7;+‘/h“f wé/‘L5‘4) = .. (34042.5‘J'+441?4.r3‘) .-: — 75.7.‘15’3‘ Amount ol' heat released = _ yofiif 3- 15. Give the correct name or structure for the following two organic compounds. [6 pts: 3 pts each] a r 9H3 CH3—CH—Ct—|-CH:CH—CH3 3-ethyI-2-methylpentan-2—ol ('3' Ir 3 a. I c ’43 .. - we. I '1 5' -411 own.— ~maH¢ /lte:( :1 3 1-! J 5. l ‘i / 4,43,,4— fiH_¢_,/&_¢h/£ a 1‘ OH CH —c,_/ 5—4.4 Aux-p —l/-M4/1‘//~z. -' 48.165“: "’ 3 Id MacDonald, CHM/020. 11/25/2008. Exam 2 I6. Diborane (BZHE) is a higth reactive compound that was once considered as a possible fuel for rockets for the U. 3. space program. Calculate AH“n for lhc synthesis of diboranc from boron and hydrogen using the information given below. [8 plsl AH (k1) 2 3(5) + 3 H:(g) —> BzHr-.(g) AHM = 1’ (a) BJ‘LIS) + 3 02(3) -’ 3203(5) + 3 H20(g) -2035 (b) H300) —> HgO(g) 44 (c) 2 3(5) + 3/2 03(g) —> 3203(5) 4273 (d) H:(g) + U2 02(g) —> H200) -286 3/; -(¢—) Bin/0&3) ,- 3 Htay)——> B; I-l‘ 9') +24%?) -(-0"~035') (a) 3.50) r7y¢£()—~+ 3%“) *Ia73 .2. A5<S)+3*LD</)-—-? 3*449)*%99 7‘ 3(4) 3 Hair) + 29627) —> .3 $.96?) 30;“) .13“) was,” 3;A/D¢f,,_> s; #57) 4. 2%(1) ~74 3(5) 2 0a)"? 3%9’ 3 (W) 2.3a) + 3 Had/0 """’ 3:. #4 4;) sé k7 <54: Egan/l; :‘a a/«a’: nail-=5) AH — _34_’<‘T_ rm _ l7. What is the specific heal capacity of gold (Au) il' 97.6 .l of energy are required to raise the temperature of I5.0 grams of gold from 25.0 °C to 75.0 °C'? I5 plsl AH 97.4 .T —- — "4' AT (I5.y)(7r.o°<-—.z£o°c.) a 0.130 {rang Specific heal capacil) of gold (Au) — _ .0 a; b \i 00 MacDonald. C HM I 020. 11/25/2008, Exam 2 IS. a. Methanol (CHgOH) often is used as a fuel in high—performance engines in race cars. Determine the amount of heat (AHM) released from combustion of methanol in the reaction below. l5 ptsl f aka—tuck .‘u if: {fa-01.44.9961 ch in A 1.6; 2 O W/wa/ 2 CH30H(I) + 394%) —> 2 C03(g) + 3 H300) A_H°1~(k.l/mol: CHJOH (l) —239 C02(g) '394 a 0 H20“) -286 Ail/m = Z} All; (rm!) - :n AHFomf) Cams“) -269 .. [:1 moI(-'37‘f;;;r 3MDI(-aré%fl-E_mal(—A37f§)r 3mol(o£§')] = [—14% Kr] - [:47exa'] = ~11éf’Ka‘ AH — "/léf'KJ- nn — b. Gasoline is a mixture of different hydrocarbons, a major component of which is octane (CSHIR). Assume for this problem that gasoline consists of pure liquid octane. Determine the amount ol‘ heat (AHM) released from combustion ol‘ octane in the reaction below. [5 ptsl a ‘ILW& '5‘ JD —- 0 2 (TKH,,<)+25 03(3) -> 16 C‘O:(g)+ I8 H3()(|) Al‘lgxu z. D‘ m"1(‘37‘3‘ + Ionlé‘iré fi-EMD((—1‘j§‘TJ-)+ Aim/(05)] =1} Hsz tar] — E— 53.? x3] =3 ‘107/‘1’ KT AH = I\|| c. Which fuel, methanol or octane, is the superior fuel for use in a racing car where weight considerations usually are very important? Hint: Compare the amount of heat released per gram of octane during combustion to that per gram of methanol. Circle your answer. [2 ptsl ‘/’$?KI 1/ “so” ("°’)(m -—- am N; «am 37 ma! - lay/y KT If 4’14'3 < ”"’/)(xmo/<,H,, = “’17-? “,7 (PM? / Methanol ((‘l-I‘OHI is superior ...
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exam 2 w answers - MacDonald. C HM1020. I...

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