Question

A stop cock connecting two bulbs of having a volume of 5 litre containing an ideal gas at 9 atm and an evacuated container having a volume of 10 litre is opened. What is the final pressure (in atm) in the two bulbs if the temperature remains the same?

Answer 1

Since the two bulbs are connected, we consider them as a closed system.
As the temperature is fixed, PV = constant

Since the 10 L bulb is empty, total volume will be 15 L
Using Boyle's law, $P_1{V}_1=P_2{V}_2$
where $P_2$ is the resultant pressure after mixing
$9\times 5=15\times P_2$
$P_R=3$ atm