Lab tests, results and sulphuric acid

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Slide 1

Lab Tests, results, and Sulphuric acid

Slide 2

Testing for carbon dioxide

Slide 3

Adding acid to carbonates

Carbonates are compounds containing carbon and oxygen. When an acid is added to a carbonate the carbonate starts to fizz. A gas called _ _ is produced.

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Slide 4

Flame tests

Slide 5

Flame tests

Compounds containing lithium, sodium, potassium, calcium and barium can be recognised by burning the compound and observing the colours produced:

Lithium

Red

Sodium

Yellow

Potassium

Lilac

Calcium

Brick red

Barium

Green

Slide 6

Metal ions

Metal compounds in a solution contain metal ions. For example, consider calcium chloride:

Calcium chloride has the formula CaCl2

Slide 7

Metal ions and precipitates

Some metal ions form precipitates, i.e. an insoluble solid that is formed when sodium hydroxide is added to them. Consider calcium chloride:

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Slide 8

Metal ions and precipitates

Some metal ions form precipitates, i.e. an insoluble solid that is formed when sodium hydroxide is added to them. Consider calcium chloride:

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Slide 9

Testing for chloride and sulphate ions

Test 1: Chloride ions

Add a few drops of dilute nitric acid to the chloride ion solution followed by a few drops of silver nitrate.

Test 2: Sulphate ions

Add a few drops of dilute hydrochloric acid to the sulphate ion solution followed by a few drops of barium chloride.

Precipitate formed = silver chloride (white)

Precipitate formed = barium sulphate (white again)

For each test state: 1) The colour of the precipitate

2) What compound it is

Slide 10

Ammonium, nitrate, bromide and iodide ions

Ammonium ions:

Add sodium hydroxide and test the gas using damp litmus paper – ammonia gas turns damp litmus paper blue.

Nitrate ions:

Add sodium hydroxide followed by aluminium powder and test using damp litmus paper.

Bromide and iodide ions:

Add a few drops of dilute nitric acid followed by a few drops of silver nitrate solution. A pale yellow precipitate should be formed for bromide ions and a darker yellow precipitate for iodide ions.