## Chemistry (7th Edition)

There are $1.97 \times 10^{-3}$ moles in a 300 mg tablet, which means there are $1.19 \times 10^{21}$ $Fe^{2+}$ ions.
1. Calculate the molar mass $(FeSO_4)$: 55.85* 1 + 32.07* 1 + 16.00* = 151.92g/mol 2. Calculate the number of moles $(FeSO_4)$ ** 300 mg = $300 \times 10^{-3}$ g = 0.300 g $n(moles) = \frac{mass(g)}{mm(g/mol)}$ $n(moles) = \frac{ 0.300}{ 151.92}$ $n(moles) = 1.97\times 10^{- 3}$ 3. Find the amount in moles of $Fe^{2+}$ ions: ** Each $FeSO_4$ has 1 $Fe^{2+}$ ion, so the ratio is 1 to 1. $1.97 \times 10^{-3} mol (FeSO_4) \times \frac{1 mol (Fe^{2+})}{1 mol (FeSO_4)} = 1.97 \times 10^{-3} mol (Fe^{2+})$ 4. Calculate the number of $Fe^{2+}$ ions: $1.97 \times 10^{-3} mol (Fe^{2+}) \times \frac{6.022 \times 10^{23} ions (Fe^{2+})}{1 mol (Fe^{2+})} = 1.19 \times 10^{21}$ ions $Fe^{2+}$.