ENVIRONMENTAL ENGINEERING ANALYSIS Fall 1996

Homework Set # 2 Out: September 19 Due: September 26

Acid Rain

• The best current estimate is that in the northeastern United States, roughly one-fourth of the SO₂ emitted to the atmosphere is oxidized to sulfate and subsequently deposited as sulfuric acid in rain and snow within the region. In the northeastern US, what is the predicted pH of the precipitation.
  
• Data : The northeastern US emits about 10⁷ tones(S) yr^-1, or 12% of the global anthropogenic SO₂, and 1/4 is oxidized to sulfate and falls as sulfuric acid in the rain or snow on the region. The "region" has an area of 10¹² m² and the annual precipitation amounts to 1.5 m.
  
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1. Calculate the concentration of sulfate
2. Write all the species present in the acid rain
3. Write all the equations needed to solve the system (pK_a1 = -3, pK_a2 = 1.9)
4. Calculate the pH of the acid rain