Question

Bulb A is 100mL and contains Helium at 1atm.
Bulb B is 500ml and contains Argon at 2atm
The bulbs are connected together by a valve.
(assume constant temperature).


What is the total pressure of the system after the valves are opened?

Answer 1

The long way to do this, but the easier way to explain, is this.
Use PV = nRT for bulb A and solve for n = mols He.
Then use PV = nRT for bulb B and solve for n = mols Ar.
Add n He + n Ar = total n
Then PV = nRT. Use total n and solve for P. (Note: you don't have a T listed so just use a convenient one but don't change it)

Answer 2

Would the total pressure be 2.19985 atm? Could you possibly help me with this one?

Answer 3

No, that isn't right.
What's the problem with plugging in the numbers? For example, for He, you can use
PV = nRT.
n = PV/RT
n = 1*0.1/(0.08206*300)
n = 0.00406

For Ar.
n = PV/RT = 2*0.500/(0.08206*300)
n = 0.406
Total n = 0.0406+0.00406 = 0.0446

Then p = nRT/V = 0.41*0.08206*300/0.600
P = ?

You can also do this a much shorter way by using P1V1 = P2V2
For He that is P2 = P1V1/V2
P2 He = 1*(100/600) = 0.167
P2 Ar = 2*(500/600) = 1.67
Total P = 0.167+1.67 = ?