What mass of calcium chloride is needed to prepare 2.000 L of a 2.25 M solution?

To calculate the mass of calcium chloride (CaCl₂) needed to prepare a 2.000 L solution at a concentration of 2.25 M, first determine the number of moles required: ( \text{moles} = \text{Molarity} \times \text{Volume} = 2.25 , \text{mol/L} \times 2.000 , \text{L} = 4.50 , \text{mol} ). The molar mass of calcium chloride is approximately 110.98 g/mol, so the mass needed is ( 4.50 , \text{mol} \times 110.98 , \text{g/mol} \approx 497.41 , \text{g} ). Therefore, you would need approximately 497.41 grams of calcium chloride to prepare the solution.