Final pressure when two gases at different pressure

[omni]

final pressure when two gases at different pressure are mixed.
The valve between a 5-L tank containing a gas (Methane) at 3 atm and a 1-L tank containing a gas ( Ethane) at 0.55 atm (both are in 50 Degrees Celsius) is opened. What is the final pressure in the tanks? (assume that there is no change in temperature).

so my idea is to Imagine that the 5 L tank contains nothing. so i get:P1=0.55 atm V1=1L P2=?, V2=6L

and in the other gas i get this: P1=3atm V1=5L P2=? V2=6L.so what i think to do is, to use this formula:P2V2=P1V1 to work out the P2 so i get P2=(P1V1)/V2

so in the first gas i get: (3*5)/6=2.5 atm

and in the second gas i get:(0.55*1)/6=0.091atm
so the final pressure is 2.5+0.09=2.6atm ?

i am not sure i use the correct formula i would like to get help here.

thanks

 

[SMA_01]

It seems right, you got the partial pressures and got the total from there

 

[omni]

ok thank you :)

 

[Borek]

I would calculate total number of moles and use it to calculate final pressure (RT cancels out if calculations are done on symbols). But your approach is perfectly valid.

 

[omni]

well
i find my way a little bit more easier. :)

thank you.