MQ1_c - l{5 pts Select the member in each efthe fellcwing...

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Unformatted text preview: l. {5 pts] Select the member in each efthe fellcwing pair that has strenger fcrces. CH3'DCH3 CHECHQOH HF KBr CHECIE CC|4 a} CH3DCH3 KBr CH2C|2 b] CHfic-HQDH KBr CC|4 c] CH30£3H3 HF CCI4 d} CHngHgDH HF CCI4 e} CchHEOl-l KBr Cchrlg 2. {5 pts} Which efthe fellcwing statements is not true? a} Carbon tetrachloride, CCls, exhibits cnly Lenden fcrces. b} Carben dicxide, {302. exhibits bcth Lendcn and dipele-dipele fcrces. c} HF has a higher bailing pcint than HBr. d) S§H4 has a lower heat at yaperizatien than HCI. e} Ethane, CHacHg, has a higher yaper pressure than ethanel. CH3CHQDH 3. (=6 pts} Arrange the fellewing ccmpeunds in crder cf increasing melting point. H H H H H H H H can H-d-d-e—cl—d—H H-d-d-c-d-euH KCI l l. l i. ll ll {CchHgflcHacHa} [CchHECHQCHQDH] a) CH30H208H3CH3 ‘5 CH3CH20H2CHQOH '5: CED { h) CH3CH2CH2CHQDH ":1 CH3CH20CH3CH3 s: KCE a: Cal] 0] CH3CH20CH3CH3 "i CchHECHECHZDH "C KCI "1 CEO d] CHECHQCHQCHQUH ‘5 CH36HEDCH3CH3 "'3 {330 "5 l e CH3CHQOCH3CJH3 *1 CEO “i KCI =2 CH3CHQCH2CHQOH 4. {5 pts) The shape cf a liquid's meniscus is determined by a} the yisccsity cf the liquid. b} the type cf material the centainer is made cf. c} the relatiye magnitudes cf cehesiye fcrces in the liquid and the adhesiye fcrces between the liquid and its container. d} the ameunt cf hydrogen bending in the liquid. e) the yclume cf the liquid 5. {5 pts] In the heating curve below. which segment corresponds to the heat capacity of the liquid? F Temperature Heat added a} AB to) BC cl CD d) DE e} EF 5. {T ptsl How much heat list} is required to convert 125.0 g of ethanol at 444°C to the vapor phase at T803? Ethanol melts at —‘ll4“C and boils at ?8“C_ MW{Ethanolj=-=l-B.U? Specific heat of solid ethanol 0.9T Jig C2 Enthalpv of fusion of ethanol 5&2 lemol Specific heat of Eiquid ethanol 2.3 Jig C. Enthalpgvr of vaporization of ethanol 38.56 Icllmol a} 1.??x1135kd h}1.t?xtfl5l<J c} sasxlotks d} tantotio e) 1?? M 'F. {T pts} A Chemistry 122 student obtained slopes of -5L‘lfl K for liquid A, -tflDD K for liquid Br and -15lIiU K for liquid (3 from plots of in P vs 1H. The heat of vaporization, sHuap, of liquid B is ; and the normal boiling point of liquid Bis than the normal boiling point of liquid [3. R = 8.315 Jlmoi K a]: 4.16 le'lTlGl higher b) 12.5 KJl'lTifll lower c) 8.31 lemol higher d} 8.31 lemol lower e} 12.5 lemol higher For questions 8 and El, sketch the phase diagram: is.) triple point = etc. ops atm {a} critical point z 1TDUC,4U atm {o} normal melting point 2 —1o”c 40 {D} normal boiling point = 125013 {E} Vapor pressure of the solid at aoflc = cpcsaim 1.1} Pressure {atm} 111.15 {not to scale) DUDE- -sc c an 1130 15c sop Temperature (DC) 8. (5 pts} Which of the following statements is correct about the compound? a] The melting point of the solid increases as pressure is increased. b] As the temperature is increased from 4000 to 1?5”C at 0.5 atm, one phase change occurs. c} The solid is denser than the liquid. d} The solid, liquid and gas coexist at the triple point. e} As the pressure is decreased from 2D atm to 0.05 atm at1iliti‘3't3. two phase changes occur. 9. [6 pts} Which ofthe following statements is false? a] Line AC represents an equilibrium condition between liquid and solid. b) When the substance is cooled from 1 50013 to 4130:: at 1.1 atm. condensation. then solidification occurs. c} When the pressure is decreased from 25 atm to 1.1 atm at 1UDUC, the liquid phase is present. d} Line ED represents deposition. e} Line AC: represents melting. it). {5 pts} Substances that have low vapor pressures have intermolecular forces and _ boiling points. a} weak low b} strong low c) strong high d} weak high f} none of the above 11. t? pts] The yapcr pressure at a substance is 1.25 atm at 1505C and 4.?5 atm at EDUUC. Calculate the molar heat at yapcrizaticn (kdi'mcU at this substance. R = 3.314 Jimel K a] 9113 le'lTlDi b) 9.11:} kJi'n‘tcl c) 689 kJimcl d] 58.9 kJi‘mct e] Q’lflfl Icllr‘nel 12. (5 points) Which cfthe fellcwing are true? a) if chrcmium crystallizes in a bedy centered cubic cell, there are twc chrcmium ater‘ns per unit cell. b) emcrpbcus sclids haye long—range repeating patterns cf atcms. icns er melecutes. c} Twc atcms are ccntalned in a face-centered cubic cell. d) Hexagonal clcse packed sclids ccntain 32% open space. e) Cubic clcse pecking fcllcws an ABABAB... packing arrangement. 13. {8 pts} Giyen the density cftitanium is 4.401 gicm3, calculate the edge length at the unit cell. Titanium crystaltizes in a bcdy centered cubic unit cell. AWfiTi} = 4?.88 a} 3.3 x tfl'fi cm s} 5.4 it 10‘s cm c] 2.6 it 10's cm s} 4.2 x 10-3 cm e} 9.1x1fl'9 cm 14. {5 pts} On the basis cfthe fellcwing descripticns, which sclid is net ccrrectly matched tc type: a} lustrcus yellcw crystalline sclid that conducts electricity --- icnic b} hard. black: sclid {MP=2350DC} which melts tc giye a ncnccnductiye liquid --— ccyalent netwch c} ncnccnducting. pink sclid melting at 650013 tc giye an electrically conducting liquid ———icntc d} red crystals with a characteristic cdcr, melting at 1?103 F— mclecular e) A blueish-white, lustrcus, scft, malleable sclid melting at 32?"? --- metallic 15. {5 ptsj a saturated solution a} has no double bonds. b} contains the maximum concentration of solute possibie, and the dissolved solute is in equilibrium with undissotyed solute. c} has a concentration lower than the solubility. d} contains more dissolved solute than the solubility allows. e} contains no solute. 16. (5 ptsl The principle reason for the extremely low solubility of sodium chloride. NaCl. in benzene. CEHB, is a} great strength of solvent—solvent interactions bl great strength of solute-solvent interactions c] great strength of solute—solute interactions d} great weakness of solute—solvent interactions e} nonspontaneity ofthe increased disorder due to mixing of solute and solyent. 1?.[5 pts) The heat of solution, al—lmn. ofa solid in water is 38.5 lzJimol. The lattice energy. aH1_ is T453 lcllmol. What is heat of hydration, aH3. of the solid? Assume aHg is negligible. Draw a picture! a} -ss4_4 itJl'mol b} sex-t ltJimol c} ass lemol d} 334.4 lemol e} 3014 lemol 13.{5 pts} Which of the following will flbe miscible based on the rule "like disSolyes like"? a} hexane {CEHMJ and cyclohexane {Gama} b} octane [Cgij and heptanot [CyHHOHji c) hexane {CEHH} and carbon tetrachloride {ccc} d} water and glycerol {HD—CHg—CHiflHl-CHQDHJ e} water and heptano] iCyHfiDH} 19. (B ptsj Examine the solubility curye for compounds A, B and C in water. 1Ir'li'hich ot the following statements is not true? '1- I]l El .. . ... ._ . _ _______..__..._ _ . _.____._._. _______._ __.____._ ..___. ___ Ell El . . . . ..__ ___ ..__ _. __.__ ._______.. as to . so ..-. . 50 .. 4|] 3-D .. . .. . ...-...._._._--_._-__.-_._u .n:_-_"_._.... . . .. .. .-.. .-_._-__._.___.._ . ..... Gflml Salute per lll'lfl'grlrn: Sal-vent 2o . " ". -_ ._ __ ___ __._.___._._________ El . . . .. .. ..._.____...___.._____ .._._.__.._._._..._.._ El 2|} 41] 50 BE! 1130 Tempsralu rs PC} a) If ?5 g of A is added to 250 g of water at 2008. 12.5 g of A is undissolyed. h} The heat ofsolution of C is exothermic. c] it a saturated solution of C in EDD g of water is heated from 0°C to 100°C, approximately 1m] 9 of C will crystallize out. d} The heat of solution ote is endothermic. e) let-1000, you would have to dissoiye 9t} gm of B in EDU g of water to make a saturated solution. 2E}.{5 pts} What is the concentration of nitrogen in water when the partial pressure of N2 ahoye the solution is [1.826 atm. Henry's Law constant for this system is 6.8 x 1121‘4 moltL atm. a)5.6x104ly1 h}1.2x103lyl c}8.2x10'3M mowers e}fi.fiiyl 21. (6 pts] What is the molatity of a 1.06 M aqueous solution of sugar, Cwaflg, which has a density of 1.14 giml'? MW[ } = 342.3 gim a} 1.3? molal In] 1.05 molal c) 0.92? molal d} 0.634 molal } D e .442 molal a 22. {F pts} Calculate the vapor pressure {mm} at 03.5% above an ideal solution containing 85.00 pm of pure methanol {CH30H, FW = 32.04} and 05.00 gm of pure ethanol ECchHQDH, FW = 400?]. The vapor pressure of methanol and ethanol at 03.5”(3 is ?1?.2 mm and 400.0 mm mercury respectively. } 133 mm ) 50? mm 985 mm ) 59'! mm } 49‘] mm 23.13-1- pts] Calculate the mole fraction of ethanol in the vapor above the solution described in |Question 0. 24.(?’ pts} In lab, 3 Chemistry,r 122 student dissolved 0.4531 g of an unknown nonelectrolvte solute in 18.?5 g of cvclohexane. The freezing point cvclohexane was lowered 2.5000. 1|.l'Iulhat is the molecular weight ofthis solute? Kf{cvclohexane} = 20.0000im 25. {6 pts} Which of the following solutions has the highest boiling point? a] ITI “32304 b} UTE m sucrose c) 0.40 m NaGH d} 0.30 rn NagPCu. e} {LTD rn NaCl 26.6? pts} Calculate the boiling point of a solution containing 0.?5 mol of ethylene glycol and 0.15 mol of NaCl in 250 gm of water. KbngO} = 0.5120Cfm a} stats in} acetic c] iolsflc d} 1o2.2i'c a medic 2?. {T pts} A solution containing 2.95 g of a nonelectrolyte substance in ?5l] mL of benzene had an osmotic pressure of 22.5 mm at colic. Calculate the molecular weight of the substance. R = 0.6821 L atrnlmol K a) 36? glmol b) 3630 glmol c} 821gimol d}259[} gimol e} 4?? gi'mol 23. [5 pts} Which of the following statements regarding colloids is not true? a) Colloids consist of particles that are large on the molecular scale but still small enough to remain suspended indefinitely. bi Coagulation is brought about by heating or electrolyte addition. c} The Tyndall Effect refers to the scattering of yisible light by colloids. d} Hydrophilic colloids remain suspended because they have many nonpolar groups on their surface that interact with water. e] Stearate ions can be used to stabilize oil in water. 20. {5 pts} For the reaction 2 Nflgig} —:- 2 N0 {g} + 03 {g} at 30000, [N021 drops from 0.0100 M to 0.00650 M in 100 seconds. What is the average rate of disappearance of N02 for this period in Misec? a} 0.000018 Misec 0} 0.0035 Misec c) 0.00?0 Miser; d} 0.0018 Misec e} 0.000035 Misec 30. {4 pts} For the reaction in Question 20. what is the rate of appearance of 0;? 3} 0.000013 Misec in} 0.0035 Miser: c) 0.00?0 Missc d} 0.0018 Mfsec e] 0.000035 Misec 31. {3 pts} In considering the instantaneous rate of reaction, what happens to this rate over time? a} The rate increases. in} The rate decreases. o} The rate remains constant ...
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This note was uploaded on 07/17/2008 for the course CHEM 122 taught by Professor Zellmer during the Winter '07 term at Ohio State.

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MQ1_c - l{5 pts Select the member in each efthe fellcwing...

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