PLS 671: Environmental Soil Chemistry


Instructional objectives for Midterm exam

  • Be able to predict the thermodynamic favorability of a chemical reaction. 
  • Distinguish between: (a) elementary and overall reactions; (b) homogeneous and heterogeneous reactions.
  • Be familiar with the elemental composition of soils relative to the Earth’s crust.
  • Use Pauling’s Rules to predict ion coordination. 
  • Calculate % ionic character in a bond.
  • Be able to calculate various parameters related to phyllosilicate clay minerals (net negative charge, CEC, molecular weight, and clay activity) and predict the mineralogy in the sample. 
  • Understand the relationship of clay mineralogy to potassium (K+) fixation and CEC.
  • Know different surface area methods, diagnostic x-ray diffraction peaks, and relate to clay mineral structure. 
  • Know the purpose for each reagent used in the soil fractionation procedure.
  • Differentiate between soil organic matter (SOM) pools and be prepared to draw representative structures.
  • Discuss major functional groups in SOM that contribute to the observed CEC as a function of pH.
  • Be able to perform pH calculations for weak acids/bases and strong acids/bases (of the monoprotic type). 
  • Given equilibrium expressions for diprotic organic acids, derive equations necessary to plot the concentrations of each species and make interpretations.
  • Be prepared for basic analytical calculations employed in the lab.