Question

This problem concerns fitting the two-parameter Margules equation to a single measurement and then generating a predicted bubble pressure at a new composition. The problem has eight parts that will be asked one-at-a-time. A phase equilibria experiment with diethyl ketone (1) + n-hexane (2) has been performed with the following measurements. P = 76.82 kPa, T = 338.15 K, X1 = 0.508, Y1 = 0.248. Vapor pressures are P, sat = 29 kPa, P, sat = 90.15 kPa. (a) At the given experimental measurements, what is Yı? 1.2932 You are correct. Your receipt no. is 164-5130 Previous Tries The correct answer for (a) is 1.2932. Use this value as you go forward. (b) At the specified experimental measurements, what is y2? 1.3025 You are correct. Your receipt no, is 164-2147 Previous Tries The correct answer for (b) is 1.3025. Use this value as you go forward. (c) At the specified experimental measurements, for the two-parameter Margules model, what is A12? Submit Answer Tries 0/3

Answer 1

X = 0.508 0.248 29Kpa 90.15 Kpa 76.82 Kpa For Binary mixtures, X: + x2 = 1 and Thus, x2 = 1-X = 1-0.508 y2 = 1-yi = 1-0.248 yı + y2 = 1 = 0.492 = 0.752 Modified Raoults Law for non-ideal liquid and ideal vapor is given as : P* yi=Yi Xi * PS For all the components Thus, P* yı=Y1 X* PS P* y2 = Y2 X2* P25 ----> (1) ----> (2) From (1), Y1 = P 76.82.0.248 1.2932 *1*P$ 0.508.29 Y = = 783: .= 1.3025 Two Parameter Margule Model is given as: In(Yı) = xị[A12 + 2x1(A21 - A12)] In(Y2)= x?[A21 + 2x2 (A12 – A21)] Substituting all the values, In(1.2932) = 0.4922 * [A12 + 2 * 0.508 * (A21 – A12)] In(1.3025) = 0.5082 * [A21 + 2 * 0.492 * (A12 – A21 )] We need to solve above 2 nonlinear equations simultaneously using program or excel. On solving the 2 equations, we get, A12 = 1.0235 A2i = 1.0616