# Problem: The mass of an evacuated 255-mL flask is 143.187 g. The mass of the flask filled with 268 torr of an unknown gas at 25 oC is 143.290 g .Calculate the molar mass of the unknown gas.

###### FREE Expert Solution

Using the ideal gas equation.

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

Isolate n (number of moles of gas):

###### Problem Details

The mass of an evacuated 255-mL flask is 143.187 g. The mass of the flask filled with 268 torr of an unknown gas at 25 oC is 143.290 g .

Calculate the molar mass of the unknown gas.

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 Molar Mass concept. If you need more Ideal Gas Law Molar Mass practice, you can also practice Ideal Gas Law Molar Mass practice problems.