Link to description of affinity chromatography, where molecules are separated on the basis of their attraction to material in the chromatographic column. Electrophoresis Electrophoresis uses a direct electric current to separate the components of a mixture by the differing electrical charge . Link to description of how the proteins in blood serum are separated by electrophoresis. Some of the pure substances isolated from mixtures cannot be further broken down. Link to discussion of elements.
Most pure substances are compounds .
In this operation, a compound has been decomposed into its constitutive elements . Note the differences between separating the components of a mixture and those of a compound. The decomposition of NaCl required a large input of energy. This is because of the strength of the ionic bonds holding the Na and Cl atoms together. The ratio of the weights of the two products are always 23 parts of sodium to 35.5 parts of chlorine.