Hydrated & anhydrous salts
- When salts are being prepared, some water can be retained within the structure of the salt during the crystallisation process
- Salts that contain water within their structure are called hydrated salts
- Anhydrous salts are those that contain no water in their structure
- A common example is copper(II) sulfate which crystallises forming the salt hydrated copper(II) sulfate, which is blue
- When it is heated, the water from its structure is removed, forming anhydrous copper(II) sulfate, which is white
- The hydrated salt has been dehydrated to form the anhydrous salt
- This reaction can be reversed by adding water to anhydrous copper(II) sulfate
hydrated copper(II) sulfate ⇌ anhydrous copper(II) sulfate + water
Hydrated copper(II) sulfate and anhydrous copper(II) sulfate
Diagram showing the dehydration of hydrated copper(II) sulfate
