# Question a2174

Jun 2, 2017

$n = 2.28$ $\text{mol}$

#### Explanation:

First, we need to find the mass of argon.

This can be done using the formula $\rho = \frac{m}{V}$; where $\rho$ is the density, $m$ is the mass, and $V$ is the volume of the substance:

$R i g h t a r r o w \rho = \frac{m}{V}$

$R i g h t a r r o w m = \rho \cdot V$

The density of argon $1.784$ ${\text{g L}}^{- 1}$:

Rightarrow m = (1.784 "g L"^(- 1)) cdot (51.0) $\text{L}$

$R i g h t a r r o w m = 90.984$ $\text{g}$

Then, let's use the formula $n = \frac{m}{M}$; where $n$ is the number of moles, $m$ is the mass, and $M$ is the molar mass of the substance:

$R i g h t a r r o w n = \frac{m}{M}$

The molar mass of argon is $39.948$ ${\text{g mol}}^{- 1}$

Rightarrow n = frac(90.984 " g")(39.948 " g mol"^(- 1))#

$R i g h t a r r o w n \approx 2.28$ $\text{mol}$