Identification of anions and gases

• Physics
• Secondary Education
• Age 12,13

28 March 2023

Identification of anions and gases

Content objectives

• Describe tests to identify the anions
• Describe tests using aqueous sodium hydroxide and aqueous ammonia to identify the aqueous cations
• Describe tests to identify the gases

The choice of the separation method depends on the ________ of the substances being separated.

nature

mass

All methods rely on a difference, usually in a _______ property such as the boiling point between the substances being separated.

physical

chemical

What method is shown below?

Separating a mixture of solids

Differences in solubility can be used to separate solids.

For a difference in solubility, a suitable solvent must be chosen to ensure the desired substance only dissolves in it and not other substances or impurities; e.g., to separate a mixture of sand and salt, water is a suitable solvent to dissolve the salt, but not the sand.

Filtration

Differences in solubility can be used to separate solids.

Used to separate an undissolved solid from a mixture of the solid and a liquid/solution ( e.g., sand from a mixture of sand and water)

When is this method used?

Crystallisation

Differences in solubility can be used to separate solids.

Used to separate a dissolved solid from a solution when the solid is more soluble in the hot solvent than in the cold (e.g. copper sulfate from a solution of copper (II) sulfate in water)

Group work

What will you do?

Plenary (Sharing)

What's next?

Laboratory Task