Question

What is the V % change of a solution prepared by dissolving 120g of Ca(OH)2 and diluting to 600 mL

Answer 1

Here we need to calculate percent concentration with the mass/volume percent. Since the statement do not specifically indicate a volume/volume percent, and they do not give a density for Ca(OH)2, we calculate for m/v percent.

We have a mass of 120 g of Ca(OH)2 and we need to dissolve this solute in enough solvent to make a 600 ml solution.

The formula to calculate mass/volume percent is:

% m/v =    mass of solute (in grams) x 100

volume of solution (in milliliters)

Volume of solution will be equal to volume of solute + volume of solvent. But in this problem they give us the total volume of solution(600 ml), so we do not need to do further calculations.

% m/v =    120 g Ca(OH)2 x 100

600 ml of solution

% m/v = 20 %