# How many grams would 6.8 * 10^23 formula units of CuCl_2 be?

May 4, 2016

The mass of $6.8 \times {10}^{23}$ formula units $\text{CuCl"_2}$ is $\approx 150$ g.

#### Explanation:

Convert the given formula units of $\text{CuCl"_2}$ to moles by dividing by $6.022 \times {10}^{23}$ formula units/mol, then determine the mass of $\text{CuCl"_2}$ by multiplying the moles of $\text{CuCl"_2}$ by its molar mass.

$1 \text{mol formula units"=6.022xx10^23 "formula units}$

The molar mass of $\text{CuCl"_2="134.452 g/mol}$.
https://pubchem.ncbi.nlm.nih.gov/compound/24014#section=Top

$6.8 \times {10}^{23} \cancel{\text{formula units CuCl"_2xx(1cancel"mol CuCl"_2)/(6.022xx10^23cancel"formula units CuCl"_2)xx(134.452"g CuCl"_2)/(1cancel"mol CuCl"_2)="150 g CuCl"_2}}$ (rounded to two significant figures)