Multicomponent Equilibrium Thermodynamics - Elements of Environmental Engineering: Thermodynamics and Kinetics - page 115

3.63 2 Acid rain occurs by dissolution of SO 3 in aqueous droplets. SO 2 from coal
burning power plants is the culprit. The reaction is SO 2 ( g ) + 0.5O 2 ( g ) →
SO 3 (g). What is the equilibrium constant for this reaction at 298 K? If the
partial pressure of O 2 is 0.21 atm, what is the equilibrium ratio of partial
pressures of SO 3 to SO 2 at 298 K?
3.64 3 Consider a 0.1 mole fraction of ammonia solution in water at 298 K. Use
the ideal solution approximation to obtain the partial pressure of water in
this system. If the actual measured vapor pressure is 3.0 kPa, obtain the
activity and activity coefficient of water in the solution.
3.65 2 Find the fugacity of a liquid A in water. The concentration of A in water
is 1 mg/L. The molecular weight of A is 78. The vapor pressure of A is
0.02 atm. Assume that A behaves ideally in water.
3.66 2 For the reaction H 2 S ( g ) → H 2 S (aq), the enthalpy of dissolution is
− 19.2 kJ/mol at 298 K. If the temperature is raised to 318 K, by how much
will the equilibrium constant of the reaction change?
3.67 3 Consider the flooding of New Orleans by Hurricane Katrina. The flood-
water from Lake Pontchartrain extended over a square area of 10 miles
× 10 miles to a depth of 3 m. Assume that the sediment from the lake
formed a thin layer under the floodwater extending over the entire
city to a depth of 1 ft. The atmosphere above the city extends to a
completely mixed depth of 1 km. The temperature is 300 K. Gasoline
components (benzene, toluene, ethylbenzene, and xylene) were observed
in the floodwaters and originated from submerged vehicles and gaso-
line pumping stations. Consider the component ethylbenzene. Apply a
level I fugacity model to obtain the fraction of ethylbenzene present
in the floodwater. Henry's constant for ethylbenzene is 851 Pa m 3 /mol,
sediment-water partition constant is 1.4 × 10 4 L/kg, and sediment density
is 0.015 kg/L.
3.68 3 Wetlands can be useful in phytoremediation of contaminants through
uptake of pollutants by plants.A wetland consists of soil, plants, and water
in equilibrium with the air above. Consider an evaluative environment with
the following volumes: air = 10 7 m 3 , water = 10 5 m 3 , soil = 10 3 m 3 ,
and plants

10 3 m 3 . Consider a chlorinated compound, TCE with the
following properties: Henry's constant 3090 kP L/mol, soil-water parti-
tion constant = 15 L/kg, plant-water partition constant = 300 L/kg, soil
density = 0.01 kg/L, and plant density = 0.1 kg/L. Evaluate the fraction
of pollutants in the plants.
3.69 2 The equilibrium constant, K eq for the dissociation of bromine into atoms:
Br 2 → Br • + Br • is6 × 10 − 12 at600 Kand1 × 10 − 7 at800 K.Calculate
the standard enthalpy change for this reaction assuming that it is constant
in the temperature range. What is the entropy change at 600 K?
3.70 3 During the flooding of a residential area of New Orleans by Hurricane
Katrina, well-mixed floodwaters containing suspended Lake Pontchar-
train sediments entered the homes and businesses of New Orleans. After
the floodwaters stagnated, sediment settled out of the water column and
was deposited on the floors and other interior surfaces of homes, where
it remained after floodwaters were finally pumped out of the city two
weeks later.A recent paper byAshley et al. [ Chemosphere 70: 833 (2008)]
provides evidence that contamination concentration in sediment deposited

=