Dissociation in chemistry refers to the process where compounds split into smaller particles, usually ions.
A molecule is the smallest particle in a chemical element or compound that has the chemical properties of that element or compound.
Ion: An ion is an atom or molecule with a net electric charge due to the loss or gain of one or more electrons.
A solvent is a substance that dissolves a solute, resulting in a solution. Solvents can be solid, liquid or gas.