Question 1 Benzene and ethanol (e) form azeotopie mixtures. Prepare a y-x and a P-x-y diagram for the benzene-ethanol system at 45°C assuming the mixture is ideal. Compare the results with the experimental data tabulated below of Brown and Smith, Austral. J. Chem. 264 (1954). (P in the data table is in bar.)

Question 2 A 50 mol% mixture of propane(1) and n-butane(2) enters an isothermal flash drum at 37°C. If the flash drum is maintained at 0.6 MPa, what fraction of the feed exits as liquid? What are the compositions of the phases exiting the flash drum? Work the problem in the following two ways.

a. Use Raoult's law (use the Peng-Robinson equation to calculate pure component vapor pressures).

b. Assume ideal mixtures of vapor and liquid. (Use the Peng-Robinson equation to obtain f^sat for each component.)

Question 3 Above a solvent's flash point temperature, the vapor concentration in the headspace is sufficient that a spark will initiate combustion; therefore, extreme care must be exercised to avoid ignition sources. Calculate the vapor phase mole fraction for the following liquid solvents using flash points listed, which were obtained from the manufacturer's material safety data sheets (MSDS). The calculated vapor concentration is an estimate of the lower flammability limit (LFL). Assume that the headspace is an equilibrium mixture of air and solvent at 760 mmHg. The mole fraction of air dissolved in the liquid solvent is negligible for this calculation.

a. Methane, -187.8°C
b. Propane, -104.5°C
c. Pentane, -48.9°C
d. Hexane, -21.7°C
e. Ethanol, 12.7°C
f. 2-butanone, -5.6°C
g. Toluene, 4.4°C
h. m-xylene, 28.8°C
i. Ethyl acetate, -4.5°C

Question 4. In the system A + B, activity coefficients can be expressed by the one-parameter Margules equation with A= 0.5. The vapor pressures ofA and B at 80°C are p_A^sat = 900 mmHg, p_B^sat = 600 mmHg. Is there an azeotrope in this system at 80°C, and if so, what is the azeotrope pressure and composition?

Also generate the P-xy diagram and xy diagram?

Question 5.

Generate a T-xy and xy diagram for the ethanol-toluene system using the two-parameter Magules equation with data from given problem

Question 6. Generate a P-xy and xy diagram for the carbon disulfide + chloroform system using the van Laar equation. You will likely have to find van Laar coe!cients for this system.

Question 7. Generate a T-xy and xy diagram for the ethanol-toluene system using the Wilson equation. You will likely have to find Wilson coe!cients for this system.

Question 8.

For their homework assignment three students, Julie, John, and Jacob, were working on the formation of ammonia. The feed is a stoichiometric ratio of nitrogen and hydrogen at a particular T and P.

Julie, who thought in round numbers of product, wrote:

1/2N₂ + 3/2H₂ ↔ NH₃

John, who thought in round numbers of nitrogen, wrote:

N₂ + 3H₂ ↔ 2/3NH₃

Jacob, who thought in round numbers of hydrogen, wrote:

1/3N₂ + H₂ ↔ 2/3NH₃

a. How will John's and Jacob's standard state Gibbs energy of reactions compare to Julie's?

b. How will John's and Jacob's equilibrium constants be related to Julie's?

c. How will John's and Jacob's equilibrium compositions be related to Julie's?

d. How will John's and Jacob's reaction coordinate values be related to Julie's?

Question 9. The following reaction reaches equilibrium at the specified conditions.

C₆H₅CH = CH_2(g) + H₂(g) ↔ C₆H₅C₂H_5(g)

The system initially contains 3 mol H₂ for each mole of styrene. Assume ideal gases.

For styrene, ΔG^of_.298 = 213.18 kJ/mol ΔH^o_f.298 = 147.36 kJ/mol

a. What is K_a at 600°C?

b. What are the equilibrium mole fractions at 600°C and 1 bar?

c. What are the equilibrium mole fractions at 600°C and 2 bar?