What happens to the mass of the substances when something dissolves?

If some solute dissolved in solvent the mass of solvent is increased.

Explanation:

Solvent is the liquid that allow some mass to dissolve in it.

Solute is the component that is dissolved in the solvent.

When some solute is dissolved in solvent the total mass of them remains the same but the individual mass changes as both are mixed.

Thus if some solute dissolved in solvent the mass of solvent is increased.