To calculate the mass of aspartame required, we'll need to use the formula: mass of solute (aspartame) = concentration x volume of solution x molar mass of solute. We know the concentration (0.15%), the volume of solution (30 mL), and the molar mass of aspartame (294.3 g/mol). So, the mass of aspartame would be: 0.15% x 30 mL x 294.3 g/mol = 0.08751 g.