Chemical Tests
Tests for gases
Flame Tests
• We can test for positive metal ions by heating solid ionic compounds in a roaring (non-luminous)
Bunsen ame
• A platinum or nichrome wire is used as it has a high melting point, is inert (unreactive) and does
not colour the ame.
Method:
1. The wire is cleaned by dipping it into a concentrated acid (e.g. HCl) and then burned in the ame
between each test to remove impurities/any substance
2. The Bunsen ame is changed to a non-luminous ame as it can be hard to see the colour
produced by the substance being tested against a luminous yellow ame and the luminous
yellow ame is not hot enough to vaporise the sample.
3. The clean wire is dipped in the solid being tested then held in the non-luminous Bunsen ame. A
recognisable colour ame will be visible.
Lithium
Sodium
Potassium
Calcium
copper
Tests for gases
Flame Tests
• We can test for positive metal ions by heating solid ionic compounds in a roaring (non-luminous)
Bunsen ame
• A platinum or nichrome wire is used as it has a high melting point, is inert (unreactive) and does
not colour the ame.
Method:
1. The wire is cleaned by dipping it into a concentrated acid (e.g. HCl) and then burned in the ame
between each test to remove impurities/any substance
2. The Bunsen ame is changed to a non-luminous ame as it can be hard to see the colour
produced by the substance being tested against a luminous yellow ame and the luminous
yellow ame is not hot enough to vaporise the sample.
3. The clean wire is dipped in the solid being tested then held in the non-luminous Bunsen ame. A
recognisable colour ame will be visible.
Lithium
Sodium
Potassium
Calcium
copper
