CW 18 - CHM 2046 Class Worksheet 18 1. Predicting...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: CHM 2046 Class Worksheet 18 1. Predicting Spontaneity Using AH and AS. - A reaction tends to be spontaneous if AH = "" and/or AS = ' 4" . IF THENPredict _ AH=— and AS=+ I; Miami/am (3 L; M: R) AH=+jand AS=— W11" W04?“ch (*7an £3 ‘ As=+. § grewjawxbl? «AM ‘hncj‘F-ti’L-sbv AH:——— and AS=-—, ‘”. 7‘1”? W '7" 2. Predicting Spontaneity Using AG = AH - T AS. ‘Ma 5 Fry. (5 n 43% “:- -~ , 'ruflitgnlfi 1 £1 D (3 3 ‘r I u . v" 0-? t L I . - Calculating AG°: I Using Tables, like with AI-I° (AG° for elements = 0) - Using AG° = AH° - T AS° hem: For reaction as H200) Ii H20(g), calculate AH°, AS" and AG° at 25 °C. a __ "" lei}va ‘fr by“): (,ZLHJQJ“( 2-9/5 g) [31.10: gtég"0iC‘/rmo\ “DSHQOgggefl EQI'QJT/IMWASE H‘M ‘j/molfd 930 t “22W "#237! LT/MO(AG°=_9i_‘EI)mJ ( n 7 Oh,- ba; Qqq— ‘242ng,1<(n9-a,i ' .Fhal' :2 g" max 10 “j o Effggtgfijljgn A§i°=AH°-TAS°andspontanei : tr»- .ovo’l'; bGaw AND g—o bH MWV‘" haww 3+ , (fl - ‘ ' "’w a p - AS Mimzm 30"”“n-t M Legw’flfig - ——‘Y‘/>S ' For H2 (1) #H20(g),AH°=+and AS°=+ u AtlowT Ag”: +— 3.0 $75.“ w batik"113M,.—:lt'.:‘~v.._n.—.=>m u AthighT 45:30qu s» «w 9 ' F0r2N02(g)s-‘N204(g),AH°=;and AS°=; u AtlowT 5‘30"?” 3—9 Yuan-A13 n A YEA—awn n AthighT 4503": -+ to «(will {4, “0+ mosaswwm, - Co(OH2)6+2 (aq) + 4 c1- (aq) ? 00014-2 (aq) + 6 H20 (1) ‘. Qbsmedmtmfltlfisshifis EA” antlathighlthisshifts 3‘ 53m mums: signs of AH° = and Ase =+ fl...— m: For H200) # H20(g), assume AH" and AS° are constant with changing T. Calculate the equilibrium temper-nature (the where of AGO = 0 = AHO _ T Asa). 1‘} D to: “ll/Own lTbS :43:- H- . I I .2— ‘5 -" :1 5 AH‘” ,, ht, —0 km - use; ,Z‘fmzu \<;. aft st; "l7: Eda. bu 4: $31111 _ sh”. "I “444‘” w“— : 310 k. T=§20i§ waft». loo: la a} 3. Relationship of AG" to the EquilibriumK. 37 g R AG°=-RT ln(K) useR=8.3l4 J/mol K) infierbra K: egg) : ME? 7 ,l W R 1 . mum: Calculate K at 25 °C, for H200) v! H20(g), using the AG° fi'om above. Also, convert the vapor pressure of water at 25 °C (23.8 'mmHg) into atm and compare. K _, Q 9 8:5” kj/AWD (legible) _ 6.3L} .44, (875”! ) (Lalgflli) —» La ¢ . ll: ‘ . K(at25°C)= 00301 :— PH20(at25°C)= 0.038an . 4. Solubility and Complex Ions. (Text section 18.6 is recommended reading.) We have discussed how some sparingly soluble salts are soluble in acids, such as how CaCO3 dissolves in HCl(aq), but this won’t work for AgCl since Cl' is not basic. The other “trick” to dissolve “insoluble” salts is to form a complex ion. AgCl dissolves in NH3 by what can be considered-a 2 step process: AgCl (s) 6* ,.AsF‘(éiil/+ 01- (ao. Ksp = 1.8 x 10-10 /”g”'('aq) + 2NH3 (as) g Ag(NH3)2+(aq), gimme? 4 -_—__w _'_"'_‘—'“ up; , l , .. F I v ' 0,4!) It aka) + 210wa .5. N44322:: Ute)?!” K .0 9’21 )(l 6249 W K : O r 0 0.233; a; Combining the 2 equations and K’s suggests that AgCl is rho} wire/l1 soluble in NH3. Using a high [NH3], however, can shift the equilibrium to the right. Eminent: (a) To dissolve 0.10 mole AgCl in 1.0 L of a NH3 solution, what final “at equilibrium” [NH3] is required? Hint: what will be [Ag(NH3) 2+] and [Cl']- in the final ' ’ :l' - (with. , , ,m d/Lq“ w"- W C“? , le/gdLL 4/15 otaglqcrlflg3>lfij :1 O'lgn‘o‘ :_ o,ng,[U LHAL WLbfiLA,JA[d .2. (IL— >(OI3 Kl fiaCNHszf] (8” L ' it w 3%,,2sg'xxpfil : 6 ti“ ...
View Full Document

This note was uploaded on 03/27/2012 for the course CHM 2046 taught by Professor Veige/martin during the Spring '07 term at University of Florida.

Page1 / 2

CW 18 - CHM 2046 Class Worksheet 18 1. Predicting...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online