The pH of very dilute solutions of weak acids – a calculation involving the application of numerical skills to the solution of a cubic equation
- Author:
Peter Michael Barling
- Publication Type:Journal Article
- Keywords:
pH;
weak acid;
conservation of charge;
equilibria;
cubic equation
- From:International e-Journal of Science, Medicine and Education
2014;8(2):24-29
- CountryMalaysia
- Language:English
-
Abstract:
This paper presents the solution to a
calculation of the pH of a very dilute solution of a weak
acid, taking into account the effect of the hydroxonium
ions generated from the ionization of the acid on the
ionization of water, also a very weak acid. To be solved
successfully, this calculation involves the concepts
of conservation of charge, pH, equilibria and the
application of the general solution to a cubic equation.
Such an exercise requires the application of skills in
algebra, and can provide a core of understanding that
can prepare advanced students for many different sorts
of calculations that represent real-life problems in the
chemical sciences. A programme is presented in C++
which enables the work of students to be individualized
so that each student in a class can work through a
slightly different pH calculation, in such a way that a
class supervisor can quickly check each student’s result
for accuracy. This exercise is presented as a potential
means of enabling students to undertake and master
similar types of calculations involving the application
of complex algebra to problems related to equilibria and
solution dynamics.
- Full text:P020150528341360616372.pdf
