# Problem: An experiment shows that a 248 -mL gas sample has a mass of 0.434 g at a pressure of 747 mm Hg and a temperature of 28 oC.What is the molar mass of the gas?

###### FREE Expert Solution

We’re being asked to determine the molecular weight of the unknown gas.

Recall that molecular weight is in grams per 1 mole of a substance.

Step1: First, we have to calculate the amount of gas in moles using the ideal gas equation.

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

P = pressure, atm
V = volume, L
n = moles, mol
R = gas constant = 0.08206 (L·atm)/(mol·K)
T = temperature, K

Isolate n (number of moles of gas):

###### Problem Details

An experiment shows that a 248 -mL gas sample has a mass of 0.434 g at a pressure of 747 mm Hg and a temperature of 28 oC.

What is the molar mass of the gas?