# A 2.03*g mass of calcium salts contains 1.33*g calcium carbonate. What is the % calcium carbonate; and what is the percentage by mass of of calcium in calcium carbonate?

Mar 9, 2017

"%calcium carbonate (by mass)"=(1.33*g)/(2.03*g)xx100%=65.5%

"%calcium (by mass)"=26.2%

#### Explanation:

So we have the $\text{%calcium carbonate, } \frac{m}{m}$. We are not finished yet, because we have to address the percentage by mass of calcium metal in calcium carbonate:

%Ca=(40.08*g*mol^-1)/(100.09*g*mol^-1)=40% with respect to calcium carbonate.

And thus the %Ca IN THE SAMPLE

=(1.33*g)/(2.03*g)xx(40.08*g*mol^-1)/(100.09*g*mol^-1)xx100%=26.2%

We have assumed that ALL of the calcium metal is present as the carbonate.