Question 2 of 3 Inoortect Incorrect Incorrect this gestion has been austomizedby

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Question 2 of 3 Inoortect Incorrect Incorrect this gestion has been austomizedby Sapling Learning Pamela Mills at Cty University of New York ICUNT, Lehman Colle Thermodynamic Table at 250c Consider the equilibrium of methanol vapor and the liquid. Substance (kJ/mol) (JWmo-K) (kJ/mol) CH, OH CH, OH -239.2 1268 -166.6 CH3OH(l) CH3OH(g) 2010 2399 162 3 What is the v pressure of the methanol at .300c? Number P 0.00434 atm What is the va pressure of the methanol at 400c? 2.09 O Previous VView Solution 2 Check Answer o Next Ext F9 Poi Gra Desi Polic You C You c. up on You ca you ge There is O eText O Help o Web He O Technic F12

Explanation / Answer

CH3OH(l) <===> CH3OH(g)

Keq = pCH3OH

DG0rxn = DG0fCH3OH(g) - DH0f CH3OH(l)

        = -162.3 - (-166.6)

        = 4.3 kj/mol

at T = 25 c = 298k , DG0rxn = 4.3 kj/mol

DG0rxn = -RTlnK

   4.3*10^3 = -8.314*298lnk

   k = 0.1763

   keq = pCH3OH(g) = 0.1763 atm

DH0rxn = DH0fCH3OH(g) - DH0fCH3OH(l)

         = -201 - -239.2

          = 38.2 kj/mol

at -30 c , vapor pressure(p1) = ?

   at 25 c , vapor pressure(p2) = 0.1763 atm

clasius-clepyron equation

ln(p2/p1) = DH0rxn/R[1/T1 - 1/T2]

ln(0.1763/P1) = (38.2*10^3/8.314)((1/243.15)-(1/298))

   P1 = 0.00544 atm

at 40 C , vapor pressure(p2) = ?

at 25 c , vapor pressure(p1) = 0.1763 atm

ln(P2/0.1763) = (38.2*10^3/8.314)((1/298.15)-(1/313.15))

p2 = 0.369 atm

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