Question

a gas with a mass of 67.24 g occupies 20.00L and 730 mmHg.what is the molar mass of the gas in g/mol?

Answer 1

The molar mass is 85.59 g/mol

Step-by-step explanation:

Given:

m = mass = 67.24 g

V = Volume = 20 L

P = pressure = 730 mmHg

Question: What is the molar mass of the gas, PM = ?

The molecular weight of any susbtance is defined as the amount of mass over the number of moles.

`PM=(m)/(n)`

According to the ideal gas law:

`PV=nRT`

Clearing the number of moles from the first equation and replacing it in the second

`PV=(mRT)/(PM) \\PM=(mRT)/(PV)`

Here,

R = constant = 62.36367 mmHg L/mol K

T = 25°C = 298 K, we assume that the temperature is the standard.

Substituting values:

`PM=(67.24*62.36367*298)/(730*20) =85.59g/mol`