Exam 1 Key

Exam 1 Key - A 7.49 g sample of a gas occupies 5.25 L at...

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Unformatted text preview: A 7.49 g sample of a gas occupies 5.25 L at STP. Could the gas be hydrazine, N2H4? Verify your answer via calculation. (8 pt) @ 525,- x {AKMOIN’Z’H :— 0.ZS'+ Vidal [UZ—H'i 22."il_ THC” .__’ $2,03/MD' .L meme! 7 ‘ iv ltmgx ,2; 0137-05 @ H‘anUaX‘l: ‘fiwa "‘ 32.03, 77 {rim 1‘5 5M2 Q5 Calc' (44.x- Hydrazine, N2H4, is highly toxic and dangerously unstable, and is usually handled as an aqueous solution for safety reasons. Draw Lewis structures (using dashed lines for bonds and pairs of dots for Zone pairs) illustrating the predominant intermolecular force responsible for the formation of an aqueous solution of hydrazine. Use 8+ and 8' symbols and dashed lines to illustrate the intermolecular force. What is the pre- dominant intermolecular force responsible for the formation of an aqueous solution of hydrazine? (8 pt) J“ 5+ J.- J+ 20+ NE! firming H\" -‘/[-‘~‘:.C')/H ’Lp—l— Hug Sift/cl" Ned/L \ 5 H/ H’ H 747,7 7 29* H’WTQ Heels Equal volumes of gases A and B diffuse through a porous pot in 20 and 10 seconds, respectively. The molar mass of gas A is 80 g/mol. What is the molar mass of gas B in g/rnol? (6 pt) Roche“ ; Rachel; (Vim/4 (’Hr 1* m B \Z “X 3.03 __.._ M 809/». Ll= M W 5F 10" I 28’05/wo) ..,. a 739°a/ml UN - gen? (10 pt) A gas cylinder contains a mixture of 2.00 g He, 12.0 g 02, and 17.0 g N2. The total pressure exerted by the gas mixture is 469 ton. What is the partial pressure of oxygen in the cylinder? (10 pt) ,WL C 2.005“; x. llamol HE: dag no! H-e. My lmd 0‘2, ___________—. 31.05 01/ a?» C “1-05. 02 x Otg'lg "‘0" 07' \1 A hydrogen gas thermometer (a sealed glass tube containg "'-gas is found to have a V0— lume of 100. cm3 when placed in an ice-water bath at 0.0 °C. When the same thermometer is immersed in boiling liquid chlorine at the same pressure, the volume of hydrogen is found to be 87.2 ems. What is the boiling point of chlofine in degrees Celsius? (6 pt) Vu: @009..." T; = 9573K. V2, 98,1201»? "'2, : Write a complete'and balanced equation for the reaction of hydrogen and nitrogen to produce ammonia. How many liters of ammonia at STP are produced when 12 g of hydrogen are reacted with 28 g of nitro- h>+ N1+ 3H2, "90291143 lakll’g’ 0‘5 H1 at \VMH’L x lubed Mt} X W ' “1-05!sz amoi H), Iw‘olm'ls . f limited @ 1 M} 3‘ 7! 3.3.4" 1' 3 135’”? ImolN1 1m! “H3 @ 3 um. a we 7. Assume that you have a saniple of gas in a cylinder with a moveable piston. Redraw the apparatus if the pressure is doubled and the absolute temperature is quadrupled. (6 pt) 8. The dissolution process is endothermic if the amount of energy released in bringing about @ 60 u interactions is less than the s u of the amounts of energy in I v overcoming 30 3re_ -So Uta and 7°|U0~ I 93’ VM+ interactions. (9 pt) +{‘- SD 9. Which of the following substances will have the strongest intermolecular forces? (4 pt) SiOz N0 LiF Cd PF3 10. Which of the following compounds has the lowest melting point? (4 pt) A1283 Mng Can A.ng 7 NaF 11. Rank the following compounds in order of increasing boiling point. (12 pt) SFz, AgCl, BeClg, CH30H' c . (57mm 19/634111: 12. 13. W” (—110 Identify the predominant type of intermolecular force depicted in each figure below. (9 pt) 8- 5+ . - + H/BI T5 ..6"" _N ' -- \,5 .. S .. /C~_\ \N' :01/5'\c1= H /5 H .5} a) H ~ b) 5 London figs g£inz€~5£QQaI€ ("n attrad‘fomxs 4‘ 7 @ H “0+ l H/lc\g/HB+ H .liol (3) 11(41— MQLLLQ term/{77m S 1‘ T @ CE 8.00 k] of heat is added to 20.0 g of ice at -120. °C. What are the final temperature and the phase(s) of the substance? (8 pt) specific heat of water 4.18 J/g°C specific heat of ice 2.03 J/g°C heat of vaporization 2260 J/g specific heat of steam 2.09 3/g°C heat of fusion 334 J/g ancof 8‘ .00 KS x mm T u-—-—-—""’_'—f- ICS’ '- 8.00 xbgj— @ T: Clo-0a) Ce}; 2 Qua “’1 H) 6001‘ 14. The density at 20 °C of a 0.500 M aqueous solution of acetic acid is 1.004 g/mL. The molar mass of acetic acid is 60.00 g/Inol. (Hint: Assume 1.00 L of solution.) (10 pt) a) What is the molality of the solution? @ @ I. owl—x 0500 Ww‘ CHM)” _ 0.5m; molt'éCQD/I—X 60-0 : 0.0 9 . _____________. , J E h‘SCda/F l i L 50]» “MO H’i’ Loot-fig. : [ooqb sag/n m L 501w LUOOLK [.000qu I L. X “04* {we} saln _ 3.9.0j 0H3 (at) H :— 97q; #20 @ 97g} #20 X4491“ : 0.?74 ij‘LO @ flaw? ( P+ 2 amm Cuzcwu 0.77tP/Cj [ho b) What is the mole fiaction of acetic acid? @ ('39 97%; MO KW : chiwiz‘ho avg/ho @ O, gmmo' C/ingD—f" : f— 0,§¢0WD| If”?! 0.50 MA Cl+3COO L} (-— a—. X U43 C doH’ ...
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Exam 1 Key - A 7.49 g sample of a gas occupies 5.25 L at...

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