Empirical formula: Simplest whole number ratio of atoms (of each element) in a compound/molecule
Molecular formula: Definite ratio, shows all atoms in a molecule
Hydrated salts:
Hydrated salts are anhydrous ionic salts with a certain number of water molecules.
e.g. $CuSO_4.5H_2O$
This gives the molar ratio thank you ethan widjaja :)
The attraction between the salt and water (ion-dipole) is relatively weak, thus if we heat the substance, we can separate the substances into the salt and water heat e.g. $CuSO_4.5H_{2}O \rightarrow CuSO_{4}+ 5H_2O$
The heat is meant to be on top of the arrow.
