At 387.5 degrees C, the vapor pressure of K is 3.25 torr and
that of Hg is 1280 torr. Over a solution 50 mol % of K in Hg, the
vapor pressure of K is 1.07 and that of Hg 13.0 torr. Calculate the
activities and activity coefficients of K and Hg in the solution.
Calculate the
mixG of 0.5 mol of K and 0.5 mol Hg at 387.5 degrees C. If the
mixS is ideal, calculate the
mixH for the equimolar solution.
Activity = pi / p* [ pi = vapour pressure and p* = vapoure pressure of pure component]
Activity of K = 1.07/3.25 = 0.329
Activity of Hg = 0.01015
aK = yK * Xk
0.329 = yK * 0.5
yK = 0.658
aHg = yHg * XHg
yHg = 0.01015 / 0.5 = 0.203
delta mix G = nRT [ X1*lnX1 + X2*lnX2]
delta mix G = 0.5*8.314*[387.5+273] [ 0.5*ln 0.5 + 0.5 ln 0.5]
delta mix G = - 1.903 KJ
delta S mix = -nR [ X1*lnX1 + X2*lnX2]
delta H mix = delta G + T*delta S
delta H mix = nRT [ X1*lnX1 + X2*lnX2] -nRT [ X1*lnX1 + X2*lnX2] = 0
At 387.5 degrees C, the vapor pressure of K is 3.25 torr and that of Hg...
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