Answer:one mole of NaCl weighs 58.44 g. A 2.5 M solution is 2.5 moles per liter (Molarity is just the number of moles per liter). Therefore, 0.5 L would contain 1.25 mol. Hence, you would need 1.25 × 58.44 g = 73 g.
Explanation:The formula for calculating a dilution is (C1) (V1) = (C2) (V2) where...
C1 is the concentration of the starting solution.
V1 is the volume of the starting solution.
C2 is the concentration of the final solution.
V2 is the volume of the final solution.