Sol1 - Chem 215, Fall 2008 Problem Set 1 ‘ Due Friday...

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Unformatted text preview: Chem 215, Fall 2008 Problem Set 1 ‘ Due Friday Sept. 5 Name: Lab TA Name: Lab Day: 1. When aluminum is ignited in bromine, aluminum bromide is formed. In a certain experiment, 5.0 g of aluminum reacted with an excess of bromine to yield 40.9 g of aluminum bromide. Calculate the theoretical and percent yield of aluminum bromide. 2m +—36f2,~> Zr‘HBr3 Males Al : S‘ 03 _ _.. I ‘ _ T O. 2- mmefls for 8C5 fyzgrzéacpc/ Zbflg‘fl/mrg 1030a 672m; A '8’} it; @‘lx5m”&5) {2"5'? Shave) : {‘WM' /C®90' 3/) 90Ler = 83670 2. Consider a 5.430 gram mixture of FeO and Fe3O4. This mixture reacts completely with an excess of oxygen to form 5.779 g of F6203. Calculate the percent by mass FeO in the original mixture. Qacicima abut. ZFe O 1' to; ’4’ Fezgifl G) ZFdsoH "r $03.4 3,267.03 (9 wit: c}ncm=o F60 (MAM/mm = 71-853/mw} 53w~x= 3mM;F%oY { “ “ =_2mS§mm£) . ‘ 577a, WM“ Fe 0 = r 3 : 3.4:atcxt0‘2' 2’ 3 iS‘i~709/m..f’ ’ famCD fled; F6503 wmwofl‘ 2: {ifih’J .-' ‘ [L a a 7I8§~9 1*me _-I- _§_ (5-330_X’9) ' 2’— Best‘s/me .X + 930* = 3 tic-mm Zrass) gfzasn 1512: X1» [H3.'70(S_‘~E3u 1) = (i$‘_~t.u)(H3.-7o)( 3.c1¢ialo“") X = ZAOQ ‘37:: Fe; (3" 2 7;;093k1wt70 3.“ ’3 81,6)0 53306; 2 . The total mass that can be lifted by a balloon is given by the difference between the mass of air displaced by the balloon and the mass of gas inside the balloon. Consider a hot-air balloon that approximates a sphere 7.00 meters in diameter, and contains air heated to 85°C. The surrounding air temperature is 21°C. The pressure in the balloon is equal to the atmospheric pressure, 745 Torr. a) Neglecting the mass of the walls of the balloon, what total mass can the balloon lift? You can assume an average molar mass of dry air, based on 78% N2, 21% Oz, 1% Ar, neglecting trace gases. ‘ : _,,,) /o.L )[Zfli 0/1/9007} W {0.70/2} LZCOI/Mjovo) ‘3 I '7} §:: “Ti U KNOW : Z-NVW Wed / (meow/:74 (fl 7'”) a m Z-I‘Hx/O‘ :nze/nwéu/ MZ/OC {&qv‘/K‘) HCXJ: ZWJ {An2/307 a/f $5“ (“Sf/C) ’7 0/7 = Wait 59r7mréq/ We“ A 3 If/ 5m —. erJr : [soumrag (29.0 t/Wc) : 3/7gx/0‘9: 3732 b) If the balloon was instead filled with enoug H2 gas at 21°C and 745 Torr to achieve the same volume as in part a), what total mass can the balloon lift? Ms 7 HL a2.“ Lojémmz713/ mw7 Ff; A 19%: Olsz) (2.0/L WM); M711? Amy? M cask/QM > (721%) /13.07/mr€):2/lk§ 0% 7 a 4%“: éH-Nvfl7; MM; 7 c) What mass could the hot air balloon in a) lift in Denver, CO, where the pressure is typically 630 Torr? , C, Al 21°C, L30 Tam V’CW' -§SO(7L€/mr6r) M (930“ “mm mad 3 (’50 (Samara) 15/1 1' £30 /30YM’6“\ 7% m: (’30 {3MB}? 320% / 1W ., .J 4. Nitrogen dioxide is primarily responsible for the orange haze seen over Los Angeles. It dimerizes to form N204 when cooled. Suppose you put 15.2 g of pure N02 in a 10.0 L flask at 250°C. You then cool it to 25°C and measure the total pressure to be 0.500 atm. What partial pressures and mole fractions of N02 and N204 are present? Hint: always write a balanced equation, in this case N02 is the reactant. ZNOZ/en" “Loatal mofils U02 : = 0330 a} ZSO‘C. “(L-061mg 02:1)“: mcfis “LOT (0} 28' {2931.) 50330-4“: " Wt @ZS‘”L (29'3") 0330- x = 0204 =>' ' 3.121.; r643 ' Mela Fr‘"\§:‘l'ion5: :; IKMOZ": O, 5 a 5. A 20.0 L stainless steel container was . am o by rogen gas and 3.00 atrn of oxygen gas. A spark ignited the mixture, producing water. What is the pressure in the container at 25°C? At 125°C? = {31-1) _ _€_\/ 0 : (Z-Oocd'm 20.01..) : ‘ red PV fl n- RT “1 aosmm 2am) Hal-I m mi-er— bra '3 ' - r - - ‘5 r .J‘ HOL: .i( Max)— ZH S m H1031”) 4 . ABS plastic is a polymer used in applications requiring shock resistance. It consists of three monomer units, Acrylonitrile (C3H3N), Butadiene (C4H6). and Styrene (CgHg). a) A sample of ABS contains 8.80% N by mass. It took 0.605 g of Br; to react completely With a 1.20 g sample of ABS plastic. Bromine reacts 1:1 (by moles) with only the butadiene molecules in the polymer (but not with the acrylonitrile or styrene). What is the percent by mass of acrylonitrile and butadiene in this polymer? only acrgjomi’nle c‘ca‘tnins tantra-39.1 \ (from: hay-e. l00,009 Folvwvf Grams U = 30 5) j5'.) MOVE-‘5 N: 2 : mv'eos acrjlomtnle . ‘ I H 9 mass CSHBM=(_obzfimo€vs){Sfi-OG 9/”...9) 43.33 gust») @355,” Gal) botadtme reads WAL, Br; i Moles EFL: .0.LOY$ agng/cfg‘mlg ~ twigs/mg: missing-4.4%,; 9n.th Cal-log: (3.-78{=2t10”3ma¢5) 34W? - 'ocfixm-’ 30‘ij QACH'HL : wan/00°70 2 mm... Q, #6. 12.32 _______ _, Fl b) What are the relative numbers of each of the monomer units in this polymer? In 1003 to?“ foam We. Flaw-e. 3539 ' ' ‘ ! -—-., I C ' : ,__ a 33-33 <33st > M M fitment U ,-C' =) muasc =17") _ ( I713 “L RH" 59.03%! Org/5M Li 6-H: ‘jchg 2) “46% 3' C9149: : 0‘17"“- IOWWM ‘3“ Mega/ratio AIBL'S= 0-QL8,’0.31L;0.L17L : 0&3f 05,4, [031, 0.515 i 0.34, 'oJu, : :1 I I a 135 ‘ : Ll : 2, :3 ‘(C S,->n ...
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Sol1 - Chem 215, Fall 2008 Problem Set 1 ‘ Due Friday...

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