To separate a compound into its component substances, you must decompose it into elements through a chemical process.
A few methods can be used to separate compounds into their component substances. One method is electrolysis, in which an electric current is applied to a substance in a liquid phase (either as a molten salt or in a liquid electrolyte). The electric current, if applied at the proper voltage, will result in decomposition of the molecule into smaller molecules and often its component elements. Electrolysis of water is one example. Another method is catalysis. Heating certain substances, for example, ethylene, in the presence of a transition metal catalyst, such as nickel, will cause them to decompose into their component elements, here carbon and hydrogen. Strategically employed chemical reactions using strong reducing and oxidizing agents can also be used to isolate elements from some compounds.
