CHEMISTRY: Partial Pressure

1. Oct 6, 2008

ttiger2k7

1. The problem statement, all variables and given/known data
The air in a bicycle tire is bubbled through water and collected at 25 $$^\circ {\rm C}$$. If the total volume of gas collected is 5.25 L at a temperature of 25 $$^\circ {\rm C}$$ and a pressure of 734 torr, how many moles of gas was in the bicycle tire?

2. Relevant equations
PV = nRT
$$n=\frac{PV}{RT}$$

R = .08206

3. The attempt at a solution

1. Convert 734 torr to atm

734/760 = .966 atm

2. Convert 25 $$^\circ {\rm C}$$ to K = 298.15 K

3. Plug those all in:

$$n=\frac{(.966 atn)(5.25 L)}{(.08206)(298.15 K)}$$

I got n=.207 moles, but the online assignment says I got it wrong.

2. Oct 6, 2008

Staff: Mentor

0.207 is a correct number of TOTAL moles. Part of this total is water vapour.