Chapter 4 Vapor Pressure Problem Set

Chapter 4 vapor pressure problem set

1. Calculate the vapor pressure at 25oC of naphthalene, phenanthrene, anthracene, pyrene and benz(a)anthracene from its boiling point by assuming 1., a constant entropy of vaporization (88 kJ/mole/K) and 2, with eq 4-33 with a Kf =1 (eq 4-18 old book). Show the equation you used and an example with the substituted numbers, then use a spread sheet

2a. Yamasaki derived the following constants using the Hamilton GC vapor pressure technique. Estimate the liquid vapor pressures for the above compounds using fluoranthene as a reference (vapor pressure at 250C = 5.21x10-5 torr); show equation and example calculation

1-DH1/ DH2 minus C

naphthalene 0.409 -3.810

phenanthrene 0.166 -0.656

anthracene 0.165 -0.607

benz(a)anthracene -0.084 2.521

2b. Estimate the solid vapor pressures from Sonnefeld’s a and b constants at 25oC; show equation and example

2c. Convert these solid vapor pressures at 25oC to liquid vapor pressures using equation 4-38 with a constant entropy of fusion of 56.4 J/(mol K, is this reasonable for all compounds??), and eq 4-40 (optional) (new book); which are higher?

2d. Estimate the average and standard deviation for the estimated four liquid vapor pressures for each compound, and assemble all your data in a table.

3. Estimated the fraction of anthracene, pyrene and benz(a) anthracene in the particle phase at the following TSP concentrations: 20 ug/m3, 120 ug/m3 (high urban), and 400 ug/m3 (high tunnel concentrations, or extremely high up-country Thailand concentrations); assume an fom of 0.75, and an average MW for the particle phase of 120 g/mole

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