If the density of methanol is 0.793 kg/L, what is its volume needed for making 2.5 L of its 0.25 M solution?
Solution:
Mass of methanol required is M = Volume of solution × Molarity of solution × Molar mass of methanol = 2.5 × 0.25 × 32 = 20 g. Volume of methanol needed = mass/density = 20/0.793 = 25.22 mL.