What is the percent mass of calcium in a calcium supplement if 1.28-g of calcium carbonate is extracted from a 2.72-g pill?

1 answer

Ca comprises 2/3 of the 1.28g CaCO3, or 0.853g

So, assuming that all of the calcium is contained in the CaCO3, the 0.853g is 31.37% of the 2.72g pill