Level: advanced
Reference: Svante Arrhenius, "On the Dissociation of Substances Dissolved in Water," Zeitschrift für physikalische Chemie 1, 631-48 (1887)
Notes: Svante Arrhenius (1859-1927) is best known to chemists for his work on electrolyte solutions and kinetics. He also attempted to model the influence of atmospheric carbon dioxide on climate (a phenomenon now known as the greenhouse effect). He was awarded the Nobel Prize in chemistry in 1903.
The terminology employed by Arrhenius can be a bit confusing to a modern student of physical chemistry. Arrhenius called the quantity α the "activity coefficient," but it is not the same thing as modern physical chemistry texts call the activity coefficient (following G. N. Lewis). To make matters more confusing, a modern physical chemist would recognize that the Arrhenius α, derived from conductance measurements, combines effects of dissociation and ionic activity in the modern sense. For weak electrolytes, α represents dissociation ratios to a good approximation, and we may neglect ionic activity coefficients. For strong electrolytes at the concentrations mentioned here, ionic activities are quite important. This exercise uses neither strong electrolytes nor ionic activity coefficients.
Comparison of the equilibrium constants computed from these data to literature values shows agreement within an order of magnitude.
Solutions: To download solutions, go to:
http://web.lemoyne.edu/giunta/classicalcs/arrweakelec.doc
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