14.1 Percentage purity of a chemical reaction product
Purity is very important e.g. for analytical standards in laboratories or pharmaceutical products where impurities could have dangerous side effects in a drug or medicine.
However in any chemical process it is almost impossible to get 100.00% purity and so samples are always analysed in industry to monitor the quality of the product.
The more a product is processed e.g. by distillation or crystallisation, the more costly the process, but the purer the product gets.
Somewhere there has to be a compromise, so it is important that before sale, the product is assayed or analysed as to its percentage purity.
It would not be acceptable e.g. in the pharmaceutical industry to manufacture a drug for treating us, with impurities in it, that may have harmful effects.
Similarly in fuels for road vehicles, which themselves have additives in to enhance engine performance, you wouldn't want other impurities that may cause engine damage.
You can apply the same sort of argument to thousands of domestic and industrial products from the chemical and pharmaceutical industries.
% purity is the percentage of the material which is the actually desired chemical in a sample of it.
MASS of USEFUL PRODUCT
PERCENT PURITY = 100 x
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in TOTAL MASS of SAMPLE