Question

Question #3973b

Answer 1

The molar mass for the gas in the example problem is `42 g/(mol)`.

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Starting with the definition of molar mass,

`molar mass = (grams)/(mol)`

and solve for the number of moles to get the equation

`mol = (grams)/(molar mass)`.

This equation can be substituted into the ideal gas law, `PV = nRT`, to get

`PV=(gRT)/(molar mass)`

and rearranging this to solve for molar mass gives

`molar mass=(gRT)/(PV)`

with this and some simple unit conversions, we can now calculate.

`molar mass = (1.62g xx 0.0821 xx 293K)/(0.9842 atm xx 0.941 L) = 42 g/(mol)`

Hope this helps.