Exam2Key - Chemistry 444 B Hour Exam#2 Each problem is...

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Unformatted text preview: Chemistry 444 B Hour Exam #2 March 26, 2008 Each problem is worth 20 pts. 1) Over the pressure region from 0 to 600 bar, the fugacity coefficient, γ , for CO 2 at 200 K is given by the following expression: 6 2 0.70 3.33 10 ( 300) for given in bar. P P γ − = + × − a) (5 pts) Sketch f/P vs P from 0 to 600 bar, where f is the fugacity. f/P= γ , so Gamma 0.600 0.700 0.800 0.900 1.000 100 200 300 400 500 600 P r e s s u r e i n b a r b) (5 pts) What is the fugacity of CO 2 at 450 bar? ( ) 6 2 6 2 / 0.70 3.33 10 ( 300) so, 0.70 3.33 10 ( 300) f P P f P P P γ γ − − = = + × − = × = × + × − at P = 450 bar, f = 450 x (0.775) = 349 bar c) (5 pts) Calculate μ (T,P) - μ °(T) for CO 2 at 225 bar at 200 K. μ (T,P) - μ °(T) = RT ln f/f°. At 225 bar f = 225 x (0.719) = 162 bar = 8.413 (JK-1 mol-1 ) x 200 (K) x ln (162) = 8.46 kJ mol-1 d) (5 pts) Calculate μ (T,P) - μ °(T) for CO 2 at 225 bar at 200 K(for ideal gas behavior). μ (T,P) - μ °(T) = RT ln P/P°. = 8.413 (JK-1 mol-1 ) x 200 (K) x ln (225) = 9.01 kJ mol-1 2) A solution containing 1.470 g of an unknown chlorinated benzene in 50.00 g of benzene boils at 80.60 °C at a pressure of 1 bar. The boiling point of pure benzene is 80.09 °C at 1 bar and the molar enthalpy of vaporization of pure benzene is 32.0 kJ/mol. a) (15 pts) Determine the molecular weight of the unknown chlorobenzene. ( ) ( ) ( ) * 2 ( ) ( ) ( ) ln ( ) ( ) ( ) ln 1 1 ln ( ) ( ) 1 ln / sol g B B B B sol g l B B B B g l B B B vap vap B B vap B T T T R T a T T T R T a a T T RT RT H a G T T R T R T μ μ μ μ μ μ μ μ = = + = = + = − = Δ Δ ∂ ∂ = Δ = − ∂ ∂ B G Here, B-benzene, g-gas, l-liquid. Now at constant pressure and composition, we can replace the partial derivatives with regular derivatives with respect to temperature. replace the partial derivatives with regular derivatives with respect to temperature....
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This test prep was uploaded on 04/13/2008 for the course CHEM 444 taught by Professor Jameslis during the Spring '08 term at University of Illinois at Urbana–Champaign.

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Exam2Key - Chemistry 444 B Hour Exam#2 Each problem is...

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