Problem 1
Write the balanced half-reaction involving \(\mathrm{O}_{2}\) that occurs in acidic waters when it oxidizes organic matter.
Problem 2
How does temperature affect the solubility of \(\mathrm{O}_{2}\) in water? Explain what is meant by thermal pollution.
Problem 3
Define \(B O D\) and \(C O D\), and explain why their values for the same water sample can differ slightly. Explain why natural waters can have a high \(\mathrm{BOD}\).
Problem 5
Write the half-reaction, used in the COD titration, which converts dichromate ion to \(\mathrm{Cr}^{3+}\) ion, and balance it.
Problem 9
Explain the phenomenon of acid mine drainage, writing balanced chemical equations as appropriate.
Problem 12
What is the source of most of the carbonate ion in natural waters? What name is given to waters that are exposed to this source?
Problem 13
Write the approximate net reaction between carbonate ion and water in a system that is not also exposed to atmospheric carbon dioxide. Is the resulting water acidic, alkaline, or neutral?
Problem 14
Write the approximate net reaction between carbonate ion and water in a system that is exposed to atmospheric carbon dioxide. Is the resulting water mildly acidic or mildly alkaline? Explain why the production of bicarbonate ion from carbonate ion does not inhibit its production from carbon dioxide, and vice- versa.
Problem 15
If two equilibrium reactions are added together, what is the relationship between the equilibrium constants for the individual reactions and that for the overall reaction?
Problem 16
Which are the most abundant ions in clean, fresh, calcareous water?
