exam1keych201

exam1keych201 - CH20l-005 Exam 1 _ Spring 2009 Pace 1 _...

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Unformatted text preview: CH20l-005 Exam 1 _ Spring 2009 Pace 1 _ Name: E E l Please print (Last. First, MI) I. Which of the following five substances contains the greatest percent nitrogen by mass? What is that mass percent? lCor11pounds:lNOlNZO lNaN03 lNHuxto3 lmnnzcgoq l (4— &5- H- 2.8 23 “'4 571' 55/0 1'52. 5’ 3547.. tarts Its/53352, n. 2% (a) compound: biz t i with greatest percentage N (b) mass percentage N: % UT. 2. A compound is found to contain 40.05% sulfur and 59.95% oxygen by weight. (a) What is the empirical formula for this compound? 5 0% . ( “ t': i' J -_ C a a x) O l-— Llfllml 3:74‘Zmol07 at?ch 32.0é-J'Iwo q I f: . COS—J'lrwol (b) If the molecular weight for this compound is 80.07 g/mol, what is the molecular formula for this compound? k. "-9 d3- E.W1P\r‘i-Ccel fidelok fl “ mags ‘? 905; 30.0 7 _ I So molecular firmolfi : e”""?""“‘l ‘gl’mv‘icfiu- 3. When 2.199 grams of a hydrocarbon, CxHy, were burned in a combustion analysis . Pm A.“ apparatus as pictured below. 7.1.56 grams of CO2 and 2.198 grams of H20 were L) +- produced. I pa tvfifi' In a separate experiment, the molar mass of the compound was found to be 54.09 g/mol. é.th Determine the empirical formula and the molecular formula of the hydrocarbon. . wé‘ym l,- @7,t5éj-£0;. *jiwg—I if C: it?) 3 go o foxmulaLLH-a (“ft-f r l - . , t 3092, 2. t‘lS’o Ha") 0'20!ch ~ e- '~ 94—“, ' I I _ '__ , . . . L: ' l l3 0' l__3,- OravLEQiH ~ (3-- y 1 _ ‘ ____ , hogtwo (.45339 wolf‘— E (3.1LZésW ( {'007777H with l “BHOL’JC‘ c;H: 1:1.5 wZ-‘B H (b) Molecular formula: Cl-1201-005 Exam 1 I _. Spring 2009 Page 2 v it" i: \ v Name. ta -— f Please print (Last. First, MI) IO --’1. According to the equatiou below, what mass of phosphorus trichloridc (137.33 g/tnol) Pig will be formed upon the complete reaction 0f21.3 grams of chlorine gas m4” (70.91 «cg/moi) with excess phosphorus (in) (123.90 g/mol)? “l h L _—-_—__-____.-_'-‘-|—_ . 134(5) +1312 (‘5) JI‘PCMI) _ ~ 4 L 5—1“?— 1 “PE”- :wa “Ya (' 7. 3’;- tvt‘rg 2 _2' 5 2 PCL ‘ I .(i i :3 {ii 2 (5- m-ji ( : TTer—ILI Ci?— "- 5. The illustration at right represents a mixture ofiocline and fluorine molecules. 1:. (a) If the molecules in the illustration at right react to form IF3 _ J Pig according to the equation: I2 + 3F, —>2 1F3 .g-w Z _i. L the limiting reagent is ,i— ‘3'“ 7 I1;— [.1 . . . .4. h ‘" :: ig (h) the number oflhgmoleeules tortned is: t ~r 1 J 6. Carbon mouoxidc and hydrogen react to produce methanol by a reaction which may he represented as: C0 + 2H2 —> CH3OH ---—H__,_3L, .3 a: {I} j/rrp! \ gozjgmt If a mixture of 2.5 g of CO and 2.5 g Of hydrogen produeed 2.4 g 01' methanol, whttt was the limiting reagent and what was the percentage. yield? (3) {Molar Masses: CI-I3OH = 32.0; C0 = 28.0; H2 : 2.02} ‘ %__a:..‘?.;j}“>‘. _l WES“: : (_'J,"..:"d”i at") e-S'WW .022; Mm _ f _ _. _ * ninth“ L" t 1.3 0J0} ("'JL" u Ub"'t’.-ml _ 3’ 2—.0 ?(‘i-fJ-.-JH . 't_ 'I J rv'. - ‘ Z I) I 2. L3th lrmt'r'2-.. tier”- it! HM“ Vim-54H L» _ ._ __. .. __ ___,_ _ ‘ rrm ‘ j i L‘J A" — l | ‘._. Cr) 6] t . . . . J pt ~55, (a)What IS the limiting reagent? I ’ _ I {ff—L-iuiti K300 , .-'.'" - ‘ VA— -— , .. —-) Fifi (b) Winn is the percent yield of methanol? \ % Tit-tear 2L: 553 .'-‘-') SJ 7. An aqueous solution is 1.00% by mass ethanol, CEHFOH, and has at density of Whit,“ __ 2“ 0.996 g/mL. What is the rnolality offlethgngl in the solution? low-) H 2;.) i . "37)“ (iii-ix.)- 1.” _ i eri (‘5 HBO .. --*-{‘—~—-’ j” -' "5‘ Ti}: 9 : C1 fit .0 til—(J (u r) (f. a; H J L - it C .9301nc2HSOH “t “A s‘\. . , __.. H .- _' .i. A. K. - _ .- V'J‘t .""i"fl ‘. Lu—‘l it} ‘J'JiUNOVW IVL in. (-7. 5' Viv-75‘; [/15 (r) “act-3’ b L’i'nffitr—‘q; uh. ‘a L "f! f. "I “I ‘ - i, - I I -‘| u ." I; ‘y - . u I _ '# i J H in 1 U 'i 'J 'fnjiifi' I ‘V 1"“ 5"} id— hv'it-é- Page? L‘t 1-‘t' D CH20|~005 Exam 1 d I Spring 2009 Page 3 Name: l‘fx LT—‘l Please print (Last. First. M!) i ":3 3“ ‘ ‘3 8. An aqueous solution is made. by dissolving 18.4 grams of ZnBr2 in 385 grants of _\\-'atcr. What is the Inolalitiof zinc bromide (225.20 g/mol) in the solution“? .1 LL, V" "'3. I _ . (D l‘ ){f’l "2.— .iIT:.:-/_"l3£_2_ —_-_ .J,‘ 3% I gm), 7”?” L [ .LLLJ..uL-) JZHBr/f @ O ‘ ’2'3‘73'“ ENR’L .3. (lab r) J 1'3 L.) iii—j Hg!) 1" Mil-UH“ 0 w an i m ZnBrz. D ts; 9. Potassium hydrogen phthalate (often written in shonhand notation as KHP) is a solid, 1 c, + 1“ _ L monoprotic acid frequently used in the laboratory to standardize strong base solutions. It has the formula of KHCKH404(204.22 g/mol). How many grams of KHl’ are needed to exactly neutralize 20.813114 of a 0.415 M potassium hydroxide solution? a. 4—: mt t<o H o- .o-Wa ' — 1 mt K H P 3.04. am r: HP —— 1- 5 t_. ROM 1 film“ K” H I rm} KH P ’1 t< Ht" fivm W") * "<2? ; I “ta-j Kn? lC-‘gKHP : J fill 3 10.11] the laboratory you dilute 5.48 mL of a concentrated 6.00 M hydroiodic acid (HI) V“ 4 1‘ lq solution to a total volume of 175 mL. What. is the concentration of the - . t t _ —-3 -. dilute solution? Q’Udnwlmitl h3_3_l_‘..<5#lat_tr)_l AL- ,3. WHO an”): Hr LL. 1 _ :iu' -..\ Jig-h] -;r‘r)’\1()--IJLP.'\-.'l .—-—--:.-.-—---: :3. tat “Bil? 011%?le (.3.lt"';3 L5 ‘ L- l l . 'l'he boiling> point. of ethanol CZHSOH (46.07 g/mol) is 78.50 “C at 1 atmosphere. A nonvolatile, nonelectrolyte that dissolves in ethanol is testosterone. (a) if l2.77 grams of testosterone, (3191-1sz (288.4 g/mol), are dissolved in 169.3 grants of" ethanol, what is the tnolality of the solution? ' Li, ‘7 if; T?“ lwl'l it _ t . A _ _ _ _I___ ...,__.___F' a— I -;'-r- ' T)", 173'; -_;'-.a.-. d " ’ LL {‘1} Wile—ch; u- cad—tum CH3CH20H _ P l. [55: -3 L3": _ (b) [t' the tnolal boiling point constant for ethanol is 1.22 “C/tn, at what temperature will the mixture boil? ‘ Ir . g/ i .. . '3 C' .. v __ t” n_ .\ , "t? _; E K Lt) W] :L i K U" l J I) I“ (J r a, b P 723.59 + a . dl‘i ‘2' -— 3. :7; \.___._._—.‘.V, - ' 2. Firs CH201-005 Exam 1 _ Spring 2009 Pa e 4 Name: Ki} 1' Please print (Last. First Ml) : OMS 12. The boiling point ofdiethyl ether CBHSO CZHS is 34.500°C at 1 atmosphere. In a laboratory experiment, students synthesized a new compound and found that when 10.10 grams of the compound were dissolved in 219.0 grams of diethyl ether‘ the solution began to boil at 34.763°C. The compound was also found to be nonvolatile and a non-electrolyte. What is the molecular weight they determined for this compound ? (I) ?; 515) j). “(1.: 0G -v~-nw~mmm%:ikm " ‘2'341'H‘5 )2“ ’J) , .-.. . . t. , r: “if 0 . is: t" “c- = t 1M a 3339011) *9 PJVS a: t | :\::l‘lzJ-_} ; _ _ 4— .J. u t 3.3 i._\ rho [Cl I) 4 Cr,” U+l hp} _ lid—l C7,,lg___j If) , LL! ‘fd {1-) ‘3 '-‘ w?" * /__ __ P__.:. ____ __‘ . i .L mo .. , I O , (11:32! 2 X go 10.10 Pqu — ‘3 W1 c‘ VJ; SPE g/mol " .41 1.7.5 1:957“ * 5-2 L2 Jt’rrnl 13. The nonvolatile. nonclcctrolyte chlorophyll, CSSHER/lgl‘s’JOS (893.50 g/mol). is soluble in diethyl ether CZHSOCEHS. Calculate the osmotic pressure generated when 1’) 9 ctrams of chlorophyll are dissolved in 205 ml. of a diethyl ether solution at 5131:. 298 [E— _ _. (a) What is the_t_nolarity of the solution? "2) o "DE-5' 6' M. | molt-11L M: W”? "1" 7' *"é‘fil-‘S'J‘J _ I')- J 7 “pl _—_ (j .0 (xvi-4" W\ L e 9-35 L “ '9’ *0 L- b' is . . . - r é 3‘ l) (h) What IS the osmotic pressure of the solution? ' « 2 atm r- L; “3101!. ., , Jim“ "cut. ,1th 8 K \-_/ Tamwtxmwwwfiw x. ’ :" l , (:4 7) (-“i’hr"\ 14. One molal (1m) aqueous solutions of each of the following solutes was prepared. 1' O [515 Which of the solutions would have the logvest freezing point"? I f ‘33 9'15 - £ (a) 1m glucose (CaHfiofi) 4] (T, :: 2 ‘ K¥ " tn ‘0’] it {s (b) 1m ethanol (CZHSOH) P :O”“- +‘. (c) lnt sodium chloride (NaCl) ”+ 5— " ‘a ((1) 1m calcium chloride (CaClj) / ~_ “~. (“£0er 6+ (e) ]m potassium nitrate (KNO3) D j (l C..’11'H_c'e‘ v-L_|l'_1"I-+‘1'J)TS 5—; Y's-.1- ) 4: “J -. ' :5"7ibxl.vi_\_XLL'-Kt'lc;‘frtfi fi‘fl "Earn-lg: I try; TTt‘t iC-verv-OL- IY‘I lite/De b-nlo'i'trn-‘n‘ :5’ “Hill. WWJF H345" ‘(Ltf'ot‘ C 3 .i j lung:- (id-LI latri- Hui “‘— C' 0113-" ‘3'") L ; i /‘ __ I 5+} + L-1 } fare) fi- .: LL: C510 1; “3’ Gift“- ,;LCt J as I. F 3 t. .\ ,- + _ I“ (g1) FF.- I 7 * J . L I fl“? C12, salute-m turmth lulu; He. C'll20l—005 Exz-nn l Sprin" 2009 P:th 5 v L. f: \ - Name: "e _' 7,! > . f 1 Please print (Last. First, MI) [6 Pie—x l5. The phase diagram shown below is that of a pure solvent. Draw the modifications to this phase diagram that would explain the Changes in the tetn[.)erttture of the l‘l'L‘CZing point and the temperature of the boiling point ot'tlie solution. Label any points on the graph that would eltnif): t_he observed changes. lztbelgttre unclear—there will beiLo _eredit awarded. {j A: fin". a; “Vet [)0 1W1“ l \ ‘ A r" v - fijlilw’r I i w i I n a t ) _l . (2* ,. (It . 600 i C) t / <:~ - 7 i- _.;-_ qld both“? -P'JIY\ e333 “in/r" 6001—:w --i - ’ ELL-J“ II - 1- I I - i . Z ‘ I in (ii-lit}: @400 !l t 9 1w: l W] P 3‘ i— i \ fit/f l?» art—if) I] w? thl k/ I' iii;- “ ill -20 —lO 0 It) 20 30 temp (0 C) —> rjELU if?! l3“) rMJ'iw‘Ci_ f')|'.\__—__> Bonus: "‘ ' [6. The lattice energy for RF : —82l kJ/rno] is represented by the equation: K+(g) +17(g) -> KF (5) NH) The enthalpy of hydration = $91 kJ/tnol and is represented by the. equation: Pant-'1 mg) + F (g) -> K'(aq) + F' (nq) C H. cl Using these data. compose 21 thermodynamic equation describing the Enthzilpy 01' Solution for KF (AH. Hz sl'iltiott A thaw-tint ; Rift-)1 K it"??? t i‘ Wt} fl _ ...[. __.--- ‘ $351) K 'i'- 25) 3* ii r"'t) 4" t" Int-f} “’3 H ” A" Kit-i; W '7) —" Wm) r F—cr.) gt“! 1 45 1 t for —“_H__'_ —_ _ _ _—— ; — 71) ref Honormedge: l\l- It“) —::-» if... an.) t. i. By my signature on the line above, I pledge that i have neither given nor received aid on this exam. ...
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This note was uploaded on 12/25/2009 for the course CHEM 201 taught by Professor Warren during the Spring '09 term at N.C. State.

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exam1keych201 - CH20l-005 Exam 1 _ Spring 2009 Pace 1 _...

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