Answer
$8.3 \times 10^{-3} \space mol \space C $
$0.10 \space g \space C$
Work Step by Step
1. Use avogadro's number as a conversion factor to find the amount of moles:
$$ 5.0 \times 10^{21} \space C \times \frac{1 \space mol}{6.02 \times 10^{23} \space C } = 8.3 \times 10^{-3} \space mol \space C $$
- Calculate or find the molar mass for $ C $:
$ C $ : 12.01 g/mol
2. Using the molar mass as a conversion factor, find the mass in g:
$$ 8.3 \times 10^{-3} \space mole \times \frac{ 12.01 \space g}{1 \space mole} = 0.10 \space g$$
