# How many grams is 5.72 * 10^21 atoms of Li?

Apr 8, 2018

$2.067 \cdot {10}^{46}$ gm

#### Explanation:

firstly, we have to calculate no. of moles
i.e. no. of moles = no. of atoms * ${N}_{A} \left(A v a g a \mathrm{dr} o ' s N u m b e r\right)$
no. of moles = $5.72 \cdot {10}^{21} \cdot 6.023 \cdot {10}^{23}$
no. of moles = $34.45 \cdot {10}^{44} = 3.445 \cdot {10}^{45}$
mass of Li = molar mass * no. of moles
=$6 \cdot 3.445 \cdot {10}^{45} = 2.067 \cdot {10}^{46}$ gm