Excerpted from Crystallization 4th ed. J.W. Mullin , pgs 90-91
Many methods of solubility expression can lead to the use of the potentially
misleading term ' percentage concentration '. For instance, an expression
such as ' a 1O per cent aqueous solution of sodium sulfate ' without further
definition, could be taken to mean anyone of the following:
10 g of Na2S04 in 100 g of water
10 g of Na2S04 in 100 g of solution
10 g of Na2S04•10H2O in 100 g of water
10 g of Na2 S04•1OH20 in 100 g of solution
If 10 g of anhydrous Na2S04 in 100 g of water were the intended description
of the solution concentration, this would then be equivalent to :
9.1 g of Na2S04 in 100 g of solution
20.6 g of Na2S04•10H2O in 100 g of solution
26.0 g of Na2S04•10H2O in 100 g of water
which gives some measure of the magnitude of the possible misinterpretation.
To make matters even worse, the term ' percentage concentration ' is often
applied on a volume basis, e.g. 10 g of Na2S04 in 100 mL of water, of solution,
and so on. |