Here's how to understand it:
* Compound: The base compound, like copper sulfate (CuSO₄)
* Dihydrate: The "di" indicates two water molecules (H₂O) are attached to the compound.
To write the formula of a dihydrate:
1. Start with the formula of the compound. For example, copper sulfate is CuSO₄.
2. Add a dot (.) to separate the compound from the water molecules.
3. Write "2H₂O" after the dot.
Example: The formula for copper sulfate dihydrate is CuSO₄ • 2H₂O
Important Note: Dihydrates are often formed when crystals are produced from an aqueous solution. The water molecules become incorporated into the crystal structure.
