A 10.0 L flask contains 1.031 g O2 and 0.572 g CO2 at 18C. What are the partial pressures of oxygen and carbon dioxide?

What are the partial pressures of oxygen and carbon dioxide? What is the mole fraction of oxygen in the mixture?

1 Answer
anor277
Dec 18, 2016

PO2=(1.031⋅g32.00⋅g⋅mol−1)×0.0821⋅L⋅atmK⋅mol×291⋅K10⋅L

Explanation:

We know from Dalton's Law of Partial Pressures that in a gaseous mixture, the partial pressure exerted by a component gas is the same as the pressure it would exert if it alone occupied the container. The total pressure is the sum of the individual partial pressures. And thus we can solve for PO2 and PCO2 individually, and then later add them together to get PTotal.

So all we have to do is use the Ideal Gas Law:

Pcomponent=ncomponent×R×TV, and use a suitable Gas constant, R, with appropriate units.

PO2=(1.031⋅g32.00⋅g⋅mol−1)×0.0821⋅L⋅atmK⋅mol×291⋅K10⋅L

=0.0770⋅atm

PCO2=(0.572⋅g44.01⋅g⋅mol−1)×0.0821⋅L⋅atmK⋅mol×291⋅K10⋅L

=0.0311⋅atm

PTotal=PO2+PCO2

And mole fractionO2=PO2PO2+PCO2, i.e. the partial pressure of dioxygen divided by the total pressure.

Related questions
See all questions in Partial Pressure
Impact of this question
23554 views around the world
You can reuse this answer
Creative Commons License