Solubility, Melting point, Evap Point...
When you want to ident unknown chemical check there solubility. Wash them with (Polar/Non-Polar) solvant, then evap the solvant, the one that you got this way are water soluble, then by heating and slightly increasing it, you can find the Melting Point of a chemical which is caracteristic to each substance. Actually this would be hard to ident about 15 substance mixed but not imposible, try to separate them one by one using their solubility, melting point, evap point etc etc