Pure substances can be compounds or elements but they contain only one substance. An impure substance is a mixture of two or more different elements or compounds.

Pure elecments and compounds melt and boil at specidfic temperatures and these fixed oints can be used to identify them

Melting point and boiling point data can be used to distinguish pure substancers ( specific fixed points) from mixtures that melt or boil over a range of temperatures)

Formulations are useful mixtures made up in definite proportions designed to give a product the best properties possible to carry out its function.

Some metal ions (including most Group 1 and 2 cations) can be identified in their compounds using flame tests

Sodium hydroxide solution can be used to identify metal ions that form insoluble hydroxides in precipitaion reactions.

You can identify carbonates by adding dilute acid which produces carbon dioxide gas. The gas turns lime water milky

You can identify halides by adding nitric acid then silver nitrate solution

You can identify sulfates by adding hydrochliroc acid the barium chloride soultion. This productes a white precipitate of barium sulfate

Modern intrumental techniques provide fast, accurate and sensitive ways of analying chemical sybstances

Flame emission spectroscopy is an example of an instrumental method

This mentod indicates which metal ions are present from their characteristic line specta and also gives the concentration of the metal ions in a solution