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Unit 1 – Day 9. Qualitative Analysis. Qualitative Analysis Techniques. Qualitative analysis uses physical and chemical properties to identify substances. We have already learned two such techniques: Ionic and covalent properties Spectroscopy
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Unit 1 – Day 9 Qualitative Analysis
Qualitative Analysis Techniques • Qualitative analysis uses physical and chemical properties to identify substances. • We have already learned two such techniques: • Ionic and covalent properties • Spectroscopy • The rest of the unit focuses on two more techniques: • Flame tests • Solubility
Recall • Two substances are mixed up. One is labelled substance A, the other substance B. • The two substances are known to be calcium bromide and dichlorobenzene (a substance made up of carbon, hydrogen and chlorine). • Substance A has a strong odour, and will not dissolve in water. • Identify substance A and B • Dichlorobenzene is substance A.
Recall • Describe how you could use a spectrometer, and the following image to identify the gas in a lighting display.
Flame Tests • Flame tests are similar to spectroscopy. • This time we are using heat to excite the electrons instead of electricity. • The colour of the flame helps to identify the substance.
Flame Tests • With flame tests, it is the metal ion that determines the colour that the compound will produce. • For example, Strontium produces a deep red flame. • Strontium chloride flame test
Flame Test Lab • In the following lab, you will need to do some flame tests. • Fill in the table of known colours, and then use these to identify the unknown solutions.