A0.642g sample of an unknown gas was collected over water at 25.0°c and 1.04 atm. the collection cylinder contained 151.3 ml of gas after the sample was released. find the molar mass of the unknown gas.

Answer : The molar mass of unknown gas is 99.8 g/mole.

Explanation :

Using ideal gas equation:

where,

P = pressure of gas = 1.04 atm

V = volume of gas =

conversion used :

T = temperature of gas =

R = gas constant = 0.0821 L.atm/mole.K

w = mass of an unknown gas = 0.642 g

M = molar mass of an unknown gas = ?

Now put all the given values in the ideal gas equation, we get:

Therefore, the molar mass of unknown gas is 99.8 g/mole.