Solved Questions on General Chemistry II - Exam | CHE 1113, Exams of Chemistry

Download Solved Questions on General Chemistry II - Exam | CHE 1113 and more Exams Chemistry in PDF only on Docsity! psier 1 Which of the following is primarily responsible for the dissolution of acetaldehyde, CH3CHO, in \ e chloroform, CHC? i eae Ged Fall 2007 Frol a) London forces too b) ion-dipole forces Ci-CO- ei ¢) dipole-induced dipole forces , 5 ' d) H-bonding ce dipole-dipole forces * 2. Which of the following substances will have the lowest boiling point? a a) CH3Br / lowest freczine & b) CHC! Llectyynes AWN d c) CH3F ¥ d) CHsI a ) cHACH,- wr 7 : eyes 2 were?’ 3. Which of the following are responsible for the dissolution of NaCI in ea 2 ton-dipole forces ¢) dipole-dipole forces d). dipole-induced dipole forces e) hydrogen bonding @) ton dispersion forces Nal \ \S MY VO \ \ 4. Which of the following liquids would make a good solvent for iodine, [2° ony A Hi sf HO sc) CH,OH @} Cci, —e) NH; au or e gene, Point asia eores woe CAT aM & — Which of the following indicates the presence of strong intermolecular forces in a tiquid? Bee vein ck 3} a low heat of vaporization <p? € SONS b) a low critical temperature a low vapor pressure @ low boiling point e) a low-molar Mass . ly, Hydrogen cyanide is produced industrially by the following exothermi¢'reaction: 2NH3(g) + 302(g) + 2CHs(g) —> 2HCN(g) + 6H2O(g) & Which of the following statements is true? we as Vv a) a) The reaction is spontaneous only at high temperature. b) The reaction is nonspontaneous at all temperatures. c) The reaction is spontaneous only at low temperatures. The reaction is spontaneous at all temperatures. ws it is impossible to predict without the AH value. 7. Which of the following statements is false? London forces exist only between nonpolar molecules. Dispersion (London) forces involve displacement of the electrons of a moiecuie. é¥ Dipole-dipole forces are most useful when comparing molecules of similar mass. London forces are most useful when comparing molecules of widely different masses. A} Permanent dipole-dipole forces exist only between polar molecules. \ 8 Each of the following substances is a liquid at - 50°C. Place these liquids in order of increasing apor pressure. & CH;-O-CH, dimethyl ether) f CHs-CH,CH, propane_¥** are gh C CHs—CHz-OH ethanol | +v¥ a) ethanol < propane < dimethyl ether ethanol < dimethyl ether < propane _£) propane < dimethyl ether < ethanol 8y dimethyl ether < ethanol < propane Sy propane < ethanol < dimethyl ether ,g SECTION 2. PROBLEMS (6 points each). x 9. From the following enthalpies of reaction: Cigraphite) + O,(g) —>¥C02(9) (Hela) + 3020) > H,0() } 2 “NPVs gana f hs wer . grange! 60% oy ¥vCES ‘ ve sh K Srangue Bon VEY \ gos AHO? = -393.5 kJ AHO = -285.8k0 ~S 1w ZL CH,OH() + 3/20,(g) —> COz{g) + 2HzO()) -: AH? = -726.4 kd 724-4 Compute AH®, in kJ, for the reaction Glgraphite) + 2H{g) + 40.(9) > CHAOH) a) -1691.5 @7 fra \= a. 47.1 a ee d) -834.1 e) 618.7 10. The normal boiling point of benzene is 80.1°C. The molal boiling point elevation constant for ey , O a) 80.5°C ‘ b) 80.9°C 3 BL,75 ona Fe em é benzene is 2.53°C/m. A 0.850 — gram sample of a nonvolatile compound with a molar mass of Ay 185 g/mol is dissolved in 4.75 g of benzene. What is the boiling point of this solution? - 0078 Xe —] hho= 1.82 K]00> ae _ 4 | JN —ehS Lif TOM An TRIS. GSC oy «OOM, CBeclere = > 03. _ pits % . . . pis.= plha. 7 \ooy. Cony Ke “8 (as f 2 ° = } pi _ 1Gl 3675: ly Arotos GOIN. | 9.620% Pceone > Bo PA ISG a we ped PC bing ee ee | Sola comoSns. 3.16, of nenvodoMie 2 noe fpore. nyarocarbon AS" of ocesohe oo, —Leenadkion_comsbois of ocerone. Sts 47 (Cl m. a . _L Anak ts Ane mola ness of ne voter NOMONO COOMA 2 ine tool gsios of pure. G.cerone €. _ Ye. sold? ore. 662I8°C_E_ 5leSC'C, _ _ | L_teseec. tive Dey eo Aine. sermla® jai Noge point. vA “ON iq eo. oO ° Bel Calesmvote, NH ef she rocmon’s ~ Neg. ky QQ) + Oz,C9). 7 No. Co) oe CH2OW. wb _ ABD med ZNWas9).e SMO by TF Bag) BWOW). = 1010 HON» + B20. > 2N%a2+ 3N,0. (AxtN ows war 20 ao NAO. oS, 7 Weg) v1 Ory) —— > Nath WW) + OW) 3 (ow) Noy + ZO. so 7 ZN Ag + 7/202 . We) £120.46) —F. WOW. RG ob rix) “W20- ——> KS «420 >. . . NG= AW TAS? a COWEN 7 sem ck AD  5 ; sncreasina hol : List the fallowing compounds in order of increasing boiling point. Explain your reasoning in‘ terms of intermolecular forces. (9 points) sae ie ly y %; OF oT. Hiehes* HyCH2CH2CHZOH. A n-butanol Hwdroeen Bors Ase , LoweS” CH3CH2CH2CH3 n-butane — ‘ Ns a7 WMA Oldig CHsCH2CH2C = O butanal = — | butanay 13 Wad a COU. we or Epr 2. _ Diethyl Oi (MW = 74.12 g/mol) has a vapor pressure of 400.0 torr at 18°C. When a sample of benzoic acid (MW = 122.1 g/mol) is dissolved in 384.0-g of ether, the vapor pressure of the Solution is 377 torr. What is the mole fraction of benzoic acid in the sglution? (10 points) mor Be nye 93.20.02 + $280.0 ee Nel pee aN RECT Poe an Ss * PNO@) 90.25 210.7 Bo H,0(1) -285.8 22,91 gant PHNOx()) A744 9 155.6 oat 15 5 ge gfeite, pL aigsaop Fares toe ite b) Describe the temperature change at which the reaction proceeds from spontaneity to nonspontaneity. (5 points) ~ 4, Indicate whether the following reactions tend to be spontaneous at low temperatures, high temperatures, all temperatures, or nonspontaneous at all temperatures. (2 points each) ee a) NoF4(g) —> 2 NF2{9) + AH? b) CaCO,(s) + —> CaO(s) + coxa) | c) No(g) + 3F:(g) —> 2NFj(g) 2 ~~ AH a {to w rome ee AH? = 178.4 kJ AH®.= = 249 kJ d) C,H,(g) + 3.0,(g) —> 2CO,(g) + 2H,0()) 5 _AH® = 1410: Bee & wen Sper iResens wi f e) NO(g) + 3 Clg) —> NOCKg) Am - bS- AHO = 38,5 — ,»5.. Substance AH; (kJ/mol) S09) 28: ~ ae hk 39 € 3D Mee AY J HCI(g) 23 7 Calculate the amount of heat evolved (in kJ) when 6.50-g of SO, reacts according to the following reaction:(10 pojnts) : WiSde ee ° 4. $0(g) + Cl(g) —— 80,Cl,(9) t ee Vv ~ ~ i a PT meg a: 2D as | ve bo Ling od : Se ‘a Ts 6. Calculate the osmotic pressure of a solution that contains 1.22 g of sucrose (Mw = 342) dissolved in 100 g of water at 25°C. (Assume the volume of the solution is 100 mL. ) (8 points) R= 0.0821 Latmimol K 2s -y27-7 ack, ie - RW 2. SSig 0C\e 77 satay PAs TT? UG a 260, os VF We: Ff =| peck fné aoe on PClais)_+ Cin sl, a le =O eA : ‘he <i x aX — ~~ xX TO E ~ ‘ 255, a YOIKI07* Me, & as: C S+305 , mel 2 .6MB MM. . — Wo, We = Cris) Cr 2exiO% ey Fey Ego nto 3} Coord} / ee “pe 2510 ¢ t L1S= 523 Pp De Cle \_} Cintas ch precvicy ~ (Met ry ef yeacten | he = 42 Ceegu. sta) \nQ = 2CAD Ne oe poe | 5. OVS, ALA, In U L, af NGS ee. 250" e” det SS RAVAN Vie [KE =76250- UN —y -G. tS es LM =