Determine the mass of calcium carbonate contained in 10 g of chalk, which has 15% impurities.

Determine the mass of calcium carbonate contained in 10 g of chalk, which has 15% impurities. To 60 g of a 10% salt solution, another 10 g of salt was added. Determine the mass fraction of salt in the resulting solution.

In order to find the mass of pure calcium carbonate, it is necessary to multiply the weight of the chalk and the proportion of calcium carbonate in it.

The weight of pure calcium carbonate will be:

m CaCO3 = 10 x 0.85 = 8.5 grams;

The weight of the salt in the original solution is 60 x 0.1 = 6 grams.

If you add 10 grams of salt to this solution, then the weight of the solution will be 60 + 10 = 70 grams, and the weight of the salt will be 6 + 10 = 16 grams;

The mass fraction of salt in the new solution will be equal to:

With salt = 16/70 = 0.2286 = 22.86%;