Three gases (8.00 of methane,CH4 , 18.0 of ethane,C2H6 , and an unknown amount of propane,C3H8 ) were added to the same 10.0-L container. At 23.0 degress celsius , the total pressure in the container is 3.90 atm. Calculate the partial pressure of each gas in the container.

Ok,look at the partial pressure post above, work it that way.

What partial pressure post?

http://www.jiskha.com/display.cgi?id=1222147804

okay can someone verify these values

The partial pressure of each gas is 1.946, 2.3345, 6.54478

no, no, and no.

How can the partial pressures add up to more than the total pressure in the flask which is at 3.90 atm.
You may want to clarify the problem, too. You have no units on the 8.00 and 18.0. I've assumed those were grams and worked the problem accordingly. First I would use PV = nRT to determine the total mols of the system.

yes it is grams

after determining the moles what is the next step

okay i got 12.7, 23.9162, and 35.072 using the formula you showed me

however, its still not giving me the correct answer

12.7, 23.9, and 35.07 WHAT?

If these are atmosphere pressure, it still adds up to more than 3.90 which is the total.
Show your work for total mols using PV = nRT.
You should get something like 1.7 or so.

What is the pressure of 8.00 of methane,, in a 10.0- container at 23.0 ?