120 grams NaCl is equal to how many molecules of NaCl?

Sep 15, 2016

$1.24 \cdot {10}^{24}$ formula units

Explanation:

$\text{NaCl}$ is an ionic compound, so there are no molecules, only formula units.

$\text{1 mol of NaCl" = 6.02 * 10^23 " formula units}$

$\text{Formula units NaCl" = "120 g NaCl" * "1 mol NaCl"/"58.44 g NaCl" * (6.02 *10^23 " formula units")/"1 mol NaCl}$

$= 1.24 \cdot {10}^{24} \text{ formula units}$

Note: 58.44 g/mol is the molecular weight of $\text{NaCl}$