# The recommended daily dose of calcium is 1200 mg. Calcium supplements often use calcium carbonate, CaCO_3, as the source of calcium. What mass of CaCO_3 should be used in a tablet so that one tablet provides the recommended daily dose of calcium?

$\text{Moles of calcium}$ $=$ $\frac{1200 \times {10}^{-} 3 \cdot g}{40.08 \cdot g \cdot m o {l}^{-} 1}$ $=$ $0.04008 \cdot m o l$.
And thus we need $0.04008 \cdot m o l$ $\text{calcium carbonate}$, i.e. a mass of $0.04008 \cdot m o l \times 100.09 \cdot g \cdot m o {l}^{-} 1$ $=$ ??g.