project
Homework
Henry's law
PARTITIONING INTO DROPLETS


SOME USEFUL DATA
GasKHK'K"
Unitsmol dm-3atm-1mol dm-3mol dm-3
CO20.0453.8x10-63.7x10-10
SO25.40.0271x10-7
NH3901.6x10-5none

Problems on Henry's Law and Partitioning

  1. Recently I had a letter from an industrial think tank that read: "Mr Brimblecombe - one of your colleagues kindly gave me your name as he said you would be able to answer my query. I believe over 75% of CO2 omissions are encapsulated by cloud formation and brought back to earth and encapsulated in the soil due to lime being a catalyst. Is this true? Regards Bernard Killingbeck". Ascertain whether it is indeed true that 75% comes down in rain. The Henry's Law constants of various gases are given in the table associated with the questions. The annual emissions from human activity is 5E15g(C) per year. Total rainwater amounts to 0.5E18 kg and has a pH of about 5.5. What are the errors in this calculation?

  2. What is the pH of a droplet in equilibrium with a pure aqueous droplet surrounded by air with the following gas concentrations: ammonia 10 ppb, sulfur dioxide 20 ppb, carbon dioxide 360ppm

    Important equilibrium constants are found in the table on the right. The dissociation constant of water may be taken as 1x10-14. You may need an equation solver to evaluate this. Something such as Borland's Eureka a wonderful old DOS based program available on Simtel Net as a zip file mrcry209.zip or I'm told you more comfortable with MatLab in a windows environment.

  3. Determine the partition of sulfur dioxide between droplets at 0.3g m-3 as a function of pH.

  4. Remote air contains has the following composition in regard to acidic and alkaline gases: NH3 14.6 ppb CO2 365 ppm HCOOH 3.6 ppb
    GasKHK'
    Unitsmol dm-3atm-1moldm-3
    CO20.043x10-6
    HCOOH 55301.77x10-4
    NH3901.8x10-5
    1. Comment on the sources of these gases
    2. Determine the pH of a droplet in equilibrium with the gas phase
    3. Explain the limitations on the accuracy of your calculations and in particular give a view or estimate of the effect of equilibration-partition of the gases into the droplet phase on the reliability of the calculation.
  5. The AEROSOL INORGANICS MODEL developed over many years provides you with easy access to a sophisticated model of aerosol thermodynamics. This is a research model and there are a set of tutorials on-line. You should at least work through some to know what the model can do...

    HOMEPAGES:M566 Air Pollution Homepage Peter BrimblecombeSchool of Environmental Sciences