Question

an aqueous solution has a mass of 490 grams containing 8.5×5103 gram of calcium ions. the concentration of calcium ions is in this solution is

Answer 1

There are several various of expressing concentration. For instance, mass percent, volume percent, Molarity, Normality, Molality, etc.

In present case, weight of solute and solvent are given, so it will be convenient to express concentration in terms of mass percent.

Given: weight of solute (Ca2+) = 8500 g
weight of solvent (water) = 490 g.
Therefore, mass of solution = 8500 + 490 = 8990 g

Now, mass percent = $\frac{\tect{Weight of solute}}{\text{Weight of solution}} X 100$
                               = $\frac{\tect{8500}}{\text{8990}} X 100$
                               = 94.55 %

Answer: Concentration of calcium ions is in this solution is 94.55 % (w/W)