Question: what is the difference between copper sulfate and copper sulfate pentahydrate?
Answer: Copper (II) sulphate pentahydrate, CuSO4⋅5H2O, indicates copper (II) sulphate in crystalline form (for ease you can say copper (II) sulphate whose crystals contain water). Copper (II) sulphate, CuSO4, indicates anhydrous copper (II) sulphate (copper sulphate which has lost its water molecules).