Some basic procedures in analytical chemistry

One of the most basic requirements in analytical chemistry is the ability to make up solutions to the required strength, and to be able to interpret the various ways of defining concentration in solution and solids. For solution-based methods, it is vital to be able to accurately prepare known-strength solutions in order to calibrate analytical instruments. By way of background to this, we introduce some elementary chemical thermodynamics - the equilibrium constant of a reversible reaction, and the solubility and solubility product of compounds. More information, and considerably more detail, on this topic can be found in Garrels and Christ (1965), as well as many more recent geochemistry texts. We then give some worked examples to show how 

This section covers the practical considerations involved in reporting the concentration of a dissolved species in solution. The term species is a generic one, and can include anything from an element in aqueous solution (e.g., copper in solution), to a dissolved compound (e.g., dissolved nitrate), to neutral species in solution, to large complexes such as proteins in solution. 

The solubility of a compound can simply be expressed, as above, in terms of grams of compound which will dissolve in 100 grams of water at a specified temperature. A more useful concept is the solubility product, which is defined as follows. If a compound (generically termed MX, where Mn+ is any metal ion and Xn is any anion) is present in a solution in excess of its solubility, then an equilibrium is set up between the dissolved species and the undissolved solid, as follows  

There is a plethora of ways of reporting the strength of a solution, and it is important to be able to interpret each correctly, and translate between equivalent measures. There are essentially two approaches - measurement in 

Despite this, mass per volume measures are the most common, and come in four types  

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