Environmental Chemistry

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Homework Assignment 6 (20 points)

 

  1. The solubility of oxygen in water is 14.74 mg/L at 0 °C. Estimate the solubility at 50 °C.
  2. A sediment sample was equilibrated with a solution of NH4+ ion, and the NH4+ was later displaced by Na+ for analysis. A total of 33.8 milliequivalents of NH4+ were bound to the sediment and later displaced by Na+. After drying, the sediment weighed 87.2 g. What was its CEC in milliequivalents/100 g?
  3. The concentration of methane in an interstitial water sample was found to be 150 mL/L at STP. Assuming that the methane was produced by the fermentation of organic matter, {CH2O}, what weight of organic matter was required to produce the methane in a liter of the interstitial water? The equation for anaerobic degradation of biomass is:
    2 {CH2O} → CH4(g) + CO2 (g)
  4. Calculate the solubility of methane, CH4, in water at 25 °C when the partial pressure of methane over the water is 76 mm/Hg. The vapor pressure of water at 25 °C is 23.76 mm/Hg.
  5. Estimate the solubility of methane, CH4, in water at 10 °C when the partial pressure of methane over the water is 76 mm/Hg.

ENV 440 Homework

Environmental Chemistry -- ENV 440
Last Updated:  02/21/04