A 1.50 liter flask at a temperature of 25°C contains a mixture of .158 moles of methane, .09 moles of ethane, and .044 moles of butane. What is the total pressure of the mixture inside the flask?

1 Answer
Oct 8, 2016

P=nRTV5atm

Explanation:

Dalton's law of partial pressures holds that in a gaseous mixture, (i) the partial pressure of any component gas is the same as the pressure it would exert if it ALONE occupied the container; and (ii) that the total pressure is the sum of the individual partial pressures.

Thus Ptotal = Pmethane+Pethane+Pbutane, and if we (reasonably) assume ideality, then:

Ptotal = ntotal×0.0821LatmK1mol1×298K1.50L

where (ntotal=nmethane+nethane+nbutane) =

(0.158+0.09+0.044)mol = 0.292mol

And so, Ptotal 5atm. You will be able to make a better estimate.