What Happens When Copper Sulphate Crystals Are Placed in Water?
When copper sulphate (CuSO4) crystals are introduced to water, a series of fascinating physical and chemical changes occur.
1. Dissolution Process
- The copper sulphate crystals begin to dissolve in the water upon contact.
- Water molecules surround individual copper and sulphate ions, breaking the ionic bonds holding the crystal together.
- This process results in a homogeneous solution of copper sulphate in water.
2. Color Change
- Initially, the blue crystals will gradually lose their solid form and the solution will take on a bright blue hue.
- This color change is due to the presence of hydrated copper ions in the solution.
3. Heat Absorption
- The dissolution of copper sulphate is endothermic, meaning it absorbs heat from the surroundings.
- As a result, the temperature of the water may decrease slightly, creating a cooling effect.
4. Formation of Hydrated Copper Sulphate
- In the solution, copper sulphate exists as hydrated copper sulphate (CuSO4·5H2O).
- This hydrated form is commonly seen in its pentahydrate state, which is a stable structure in aqueous solutions.
5. Practical Applications
- The blue solution of copper sulphate has various applications, including use as a fungicide and in electroplating.
- It is also utilized in laboratories for educational purposes to demonstrate solubility and chemical reactions.
In summary, dissolving copper sulphate crystals in water results in a vibrant blue solution, a drop in temperature, and the formation of a hydrated compound, showcasing both physical and chemical transformations.

It will gain water of crystallization (CU s04.5H2O)