Calculate the mass of calcium carbonate that contains 1.00 mol of oxygen atoms.

Calcium carbonate’s molar mass is 100.086g/mol.

Its molecular formula is CaCO₃. In one mole of calcium carbonate, there is one calcium (Ca) atom, one carbon (C) atom, and three oxygen (O) atoms. In other words, there are three moles of oxygen for every one mole of calcium carbonate.

We would like to figure out what mass of calcium carbonate contains 1.0 mol of oxygen atoms. Now that we know one mole of calcium carbonate contains three moles of oxygen, we know we’ll have to divide by three to get just 1.0 mol of oxygen (and 1/3 of a mole of calcium carbonate). Then we can convert between moles and grams.

(1 mole O atoms) * (1 mole CaCO₃ / 3 moles O atoms) * (100.086g CaCO₃/ 1 mole CaCO₃) = 33.362g CaCO₃

Taking significant figures into account (1.00 has three significant figures): = 33.36g CaCO₃