AP Chemistry Thermodynamics WS 0809 key

AP Chemistry - AP Chemistry Thermodynamics AP Chemistry Thermodynamics WS 0809 Name Date Per 1 The following equation represents the essential

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Unformatted text preview: AP Chemistry: Thermodynamics AP Chemistry Thermodynamics WS 0809.doc Name: Date: Per: 1. The following equation represents the essential change that takes place during the fermentation of glucose to ethanol: C5H1205(5) —) 2C2H50H(|) + 2C02(g) Is AS° positive or negative? Explain. 57"“; f4 7/mco se, Ma’ng £14914 [ix/5‘ Wécwé)’ Mazda/$7) a. 545 is (fie/gm,(‘c12,,—g_ /s Act-7‘ uremic“; M AS” A} /as/7/zu-¢_ 2. Calculate the change of entropy, AS°, at 25.0°C for the reaction in which urea is formed from NH3 and C02. 2NH3(9) + C02(g) --) NH2CONH2(aq) + H200) The standard entropy of urea is 174 J/molK. See the text appendices for additional values. D 4‘5 ‘ a/7V*7d)"(2x/93+219’)]77/< : 'ZS‘éT/K 3. Using values of AH°f and 5°, calculate the standard free energy change, AG°, for the following reaction at 25.0°C. N2(g) + 3H2(g) —> 2NH3(9) AH o 3 [fizwfigflv ,0] LT : 7?. 9kg“ AS” = BXI‘PZ‘W/mé + 3x (2041072: 4%“ 0 07/4 (j A Go : (Mag TAS u ,— — fifty ._ (a??K)(ag,/95’0 K‘J/k) : ’32,? #3“ 4. Using standard free energies of formation, calculate AG° for the combustion of 1 mol of ethanol, CzHSOH, at 25.0°C. C2H50H(|) + 302(9) —) 2C02(g) + 3H20(g) At?” 3 [3/‘397'9)+3(‘225é)‘ (’/7%9)] k3" " [r/ZWflAII 5. Calculate AH° and AG° for the reaction KCI03(5) —) 2KC|(S) + 302(9) Interpret the signs obtained for AH° and AG°. Values of AH°f (in kJ/mol) are as following: KC|03(5) = - 397.7; KCI(5) = -436.7. Similarly, values of AG°f (in ld/mol are: KCl03(s) = -296.3; KC|(5) = -408.8. Note that 02(9) is the reference fOrm of the element, so AH° = AG°f = 0 for it. AIL/0 : Ex/-Yzél7),2 r/.397,7‘/] t be" =‘ [2x (-wt» 8) » 2x(»2%'3)j/<r : I!” is Ma+l~wm"¢ flanflmj 7f’f 0147 M71— Zfiy'z‘fi 06,0 {Ml/age; L7mz/Iénm ,SZWS/é/ fro—ptuarf‘ Slott- ‘ 6. Write expressions for the “thermodynamic” equilibrium constants for each of the following reactions: a. 2NH3(g) + C02“) (-) NHzCONH2(aq) + H200) b. AgC|(s) (-) Ag+(aq) + C|-(aq) 2 P /(" mij—C/j 7. Find the value of the equilibrium constant K at 25°C (298K) for the reaction 2NH3(g) + C02(g) (—) NHzCONH2(aq) + H20(|) The standard free energy change, AG°, at 25.0°C equals -13.6kJ A6“: yer/mt /n/c = My,“ ‘ ’lgléx’oz I a ab, 3 A : /’l k {FguziAzqg k e 8. Calculate the equilibrium constant KSp at 25.0°C for the reaction: A9C|(s> <-> A9+(aq) + C"(aq) using standard free energies of formation. A6" a [(77, I 43 ,1 3) _ z- [09. 8)] k3— v v “"65 : 51% >0ho fizk; 060: fiSéX/fl - :'27. : —22.vs‘..l: 40} ’97 4.220% 75' k6 ' ZX’O 9. a. What is AG° at 1,000.°C for the following reaction? CaCO3(5) 6-) Ca0(s) + C02(g) Is this reaction spontaneous at 1,000.°C and 1.00atm? éf/‘E 27-53321 —3q3,s’) —['/20é.9>j k3 = “335' AS” “I [/3672 +2/3»7)‘ (‘72)?)37/1/ 3 [5’90 7//< Atr" 1:7 3 ./ \ b. What is the valueQ of Kp at 1,000.°C for this reaction? What is the partial pressure of C02? ’- _,_ LI /»/4— 43—6 = 2404/9 32.27: /(;/(’p cez23?9_g K“ 7' - 50 3 / )< /273 k/ Sgt PkH’Jfros-smj 64': /7'?)41ZM 10. To what temperature must magnesium carbonate be heated to decompose it to MgO and C02 at 1.00atm? Values of AH°f (in kJ/mol) are: M906) = -601.2; MgC03(s) = -1111.7. Values of 5° (in J/K) are: M905) = 26.9; MgCO3(s) = 65.9 —.> .f My w3(‘) (2") Cflpgj) AH" :[Z-zezs 4 ('éa/.z)) — (ml/.7} 3 H7 L—r : n7,va 43" {(7)17 4' aév‘i) ’(65’. 7) ‘ /7£/.7:r - fl ‘ ) A6030 : mixing” 0-2/2/0021- 71/777: ...
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This note was uploaded on 12/07/2011 for the course CHEM 100 taught by Professor Feebeck during the Fall '10 term at Purdue University-West Lafayette.

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AP Chemistry - AP Chemistry Thermodynamics AP Chemistry Thermodynamics WS 0809 Name Date Per 1 The following equation represents the essential

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