question_answer 42)

Calculate the amount of benzoic acid (C6H5COOH) required for preparing 250 mL of 0.15 M solution in methanol.

Answer:

Molarity (M) M = 0.15 M = 0.15 mot L?1; Molar mass of solute (C6H5COOH) = 7 x 12 + 6 x 1 + 2 x 16 = 122 g mol?1 Volume of solution = 250 mL = 0.25 L (0.15 mol L?1)   Mass of solute = (0.15 mot L-1) x (122 g mol-1) x (0.25 L) = 4.575 g