Can you help me with this AP Chemistry gas laws problem?

Question

Consider two flasks, the first flask has 2.00L of hydrogen at a pressure of 475 torr, the second has 1.00 L of nitrogen at a pressure of 0.200 atm. If the stopcock between the two flasks is opened what is the total pressure? Assume the total volume is 3.00L

Answer 1

For such a problem, you can use Boyle's law of constant temperature.

P1V1 = P2V2.  Just apply this to each gas separately and add the pressures at the end.

For Hydrogen:  P1=475 torr; V1=2.00L; P2=?; V2=3.00L

(475 torr)(2.00L) = (P2)(3.00L0

P2 = 316.7 torr

For Nitrogen:  P1=0.2 atm; V1=1.00 L; P2=?; V2=3.00L

(0.2 atm)(1.00 L) = (P2)(3.00L)

P2 = 0.067 atm

Since we have different units of pressure (torr and atm) we must convert one of them.  I've chosen to convert the torr to atm.  Thus, 316.7 torr x 1 atm/760 torr = 0.417 torr

Total pressure = 0.417 atm + 0.067 atm = 0.484 atm