Page 60 - Soil and water contamination, 2nd edition

Basic environmental chemistry 47

2.11 FURTHER READING ON BASIC CHEMISTRY
The following textbooks on basic chemistry cover similar but more detailed material at this
level:
• American Chemical Society, 2005, Chemistry, A General Chemistry Project of the American
Chemical Society, (New York: W.H. Freeman).
• Metiu, H., 2006, Physical Chemistry, Thermodynamics, (London: Taylor and Francis).
• Rosenberg, J. L., Epstein, L., and Krieger, P., 2013, Schaum’s Outline of College Chemistry,
10th edition, (New York: McGraw-Hill).
• Timberlake, K.C. and Timberlake, W., 2014, Basic Chemistry, 4th edition, (Upper
Saddle River, NJ: Prentice Hall).

EXERCISES
2+
1. The concentration of Ca in a freshwater sample is 100.2 ppm. Recalculate this
concentration in
a. mg l -1
a. mmol l -1
b. meq l -1

2. Given the following composition of spring water:
Cations Concentration Anions Concentration
mg l -1 mg l -1
Na + 8.7 Cl - 2.3
K + 1.1 HCO 3 - 255
Ca 2+ 43.7 SO 4 - 5.5
Mg 2+ 21.6 NO 3 - 4.8
+ -4.5
H 10 (pH = 7.5)
-1
a. Convert these concentrations into meq l .
b. Check whether the charges of the cations and anions balance each other. Which ions
can be ignored for this check?
c. Estimate the electrical conductivity of this solution.
d. Calculate the ionic strength of this solution.
e. Calculate the activity coefficients for the different ions at 25 °C. What can be
concluded?
3. Describe the spontaneity of a chemical reaction in terms of enthalpy, entropy, and
temperature.

4. a. Define fugacity.
b. Explain why the fugacities in each phase are equal in each phase at equilibrium.
c. Describe in your own words how the fugacity concept can be used to estimate
partitioning of substances amongst phases.
3
5. Consider a simple lake ecosystem of 10 000 m . The lake contains 1000 kg sediment
and 350 kg fish. An amount of 1 kg of cadmium is released into this lake. Calculate
-1
-1
-1
the concentrations in water (mg l ), sediment (mg kg ), and fish (mg kg ) given a

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