Question

A 260-mL flask contains pure helium at a pressure of 743 torr. A second flask with a volume of 480 mL contains pure argon at a pressure of 715 torr.

If the two flasks are connected through a stopcock and the stopcock is opened, what is the partial pressure of helium? in torr

If the two flasks are connected through a stopcock and the stopcock is opened, what is the partial pressure of argon? in torr

If the two flasks are connected through a stopcock and the stopcock is opened, what is the total pressure? in torr

Answer 1

I assume they are both at the same temperature initially.

Parial pressure is dependent on mole ratio. n=PV/RT in each flask, find n for each first.
Then ADD the n for each. That is the N for the combined.
PV=NRT now solve for P for the combined gases.

Parg+Phelium= P
Parg=narg/N * P
Phelium= nhelium/N* P

Answer 2

752 torr of He
582 torr of Ar
total=1334 torr