I don't understand this Vapor Concept problem?

[Mackydoodle]

Homework Statement

If oxygen gas occupies 25mL at -25 'C and 65 mm Hg.
What is the volume at 25 'C and 350 mmHg?

Homework Equations

P1+P2+P3=Ptotal

The Attempt at a Solution

I am really not sure how to do this :(
I think maybe I figured it out. Please see below!

 

[bigfooted]

I don't understand P1+P2+P3=Ptotal.

The volume of a gas changes, depending on pressure and temperature. Do you know a law that describes this? (It is a law that describes an ideal gas)

 

[Mackydoodle]

The ideal gas law equation

Ok I think I might have the answer this is what I cam up with but I am not sure...
Here it is:

25mL/248K = X/298K

Which equals 30.04mL (I still don't believe this is right)

 

[Borek]

P1+P2+P3=Ptotal

The ideal gas law equation

It has nothing to do with the ideal gas equation. If anything, it looks like Dalton's law.

Ok I think I might have the answer this is what I cam up with but I am not sure...
Here it is:

(P1V1)/T1=(P2V2)/T2

V2=(65x25x318) / (350x248) = 4.2

Correct approach, but you need to hone your calculator skills.