Practical videos: identifying ions

This video from Malmesbury Education shows how to use flame tests and chemical tests to identify both metal and non-metal ions in unknown solutions.

First, Mrs Peers-Dent tests metal ions using flame tests. The demonstration uses chloride solutions containing potassium, lithium, calcium, copper and sodium. In the video, the flame tests are peformed in two ways: one using a nichrome wire and the other using a spray bottle. The video demostrates how to perform the flame tests and describes which colours to expect for each sample. It starts with the potasium solution, as this can be the hardest flame to see, and ends with sodium, since this creates the brightest flame and can interfere with other tests. 

From 5:02 the video moves on to non-metal ions, all samples of sodium containing different non-metal ions (sodium sulfate, carbonate, chloride, bromide and iodide). Three simple chemical tests to identify the ions are shown: testing with hydochorlic acid (bubble test), testing with hydochorlic acid and barium chloride (precipitation test), and testing with nitric acid and silver nitrate (precipitation test). 

Once your students understand how to use flame and chemical tests, they will be able to investigate how a combination of these tests can be used to work out the metal and non-metal parts of an unknown solution.