# How many moles of sodium chloride are present in 58*g of the salt?

Feb 15, 2017

The molar mass of sodium chloride is in fact $58.44 \cdot g$.....

## Molar mass of NaCl

$=$ $\text{Atomic mass of sodium + atomic mass of chlorine}$

$=$ $\left(22.99 + 35.45\right) \cdot g \cdot m o {l}^{-} 1.$

From where do you get these atomic masses?

The number of moles of sodium chloride in a mass of $58 \cdot g$ sodium chloride is given by the quotient,

$\text{Mass"/"Molar mass} = \frac{58 \cdot \cancel{g}}{\left(22.99 + 35.45\right) \cdot \cancel{g} \cdot m o {l}^{-} 1}$ $=$

$\text{A tad under one mole.}$

Note that this is dimensionally consistent in that $\frac{1}{m o {l}^{-} 1} = \frac{1}{\frac{1}{m o l}} = m o l$ as required.