We’re being asked to **calculate for the molar mass of a gas **using the **plot of density and pressure**

Recall that to calculate using density, we can use the **ideal gas equation**.

$\overline{){\mathbf{P}}{\mathbf{V}}{\mathbf{=}}{\mathbf{n}}{\mathbf{R}}{\mathbf{T}}}$

$\frac{\mathbf{P}\overline{)\mathbf{V}}}{\overline{)\mathbf{V}}}\mathbf{=}\frac{\mathbf{n}\mathbf{R}\mathbf{T}}{\mathbf{V}}$

$\mathit{P}\mathbf{=}\frac{{\mathbf{n}}\mathbf{RT}}{\mathbf{V}}$

${\mathit{n}}{\mathbf{=}}\frac{\mathbf{m}\mathbf{a}\mathbf{s}\mathbf{s}\mathbf{}\left(\mathbf{m}\right)}{\mathbf{m}\mathbf{o}\mathbf{l}\mathbf{a}\mathbf{r}\mathbf{}\mathbf{m}\mathbf{a}\mathbf{s}\mathbf{s}\mathbf{}\mathbf{\left(}\mathbf{M}\mathbf{\right)}}$

The density of a gas of unknown molar mass was measured as a function of pressure at 0 ^{o}C, as in the table below.

Pressure | |||||

(atm) | 1.00 | 0.666 | 0.500 | 0.333 | 0.250 |

Density | |||||

(g/L) | 2.3074 | 1.5263 | 1.1401 | 0.7571 | 0.5660 |

Determine a precise molar mass for the gas. *Hint:* Graph d / P versus P.

Frequently Asked Questions

What scientific concept do you need to know in order to solve this problem?

Our tutors have indicated that to solve this problem you will need to apply the Ideal Gas Law Density concept. If you need more Ideal Gas Law Density practice, you can also practice Ideal Gas Law Density practice problems.