# Decrease in system pressure do to gas dissolution?

A system of fixed volume contains two fluids as illustrated in the figure below, in equal volumes. Their pressures are both equal and high (much greater than atmospheric pressure).

Initially the liquid and gas are separated by a seal. Assuming the seal has negligible volume, the seal is instantaneously removed and the liquid and gas phase are hydraulically connected. Let's assume the gas behaves ideally, does not react with the liquid, and the equilibrium process is isothermal.

1. Does the system's pressure decrease do to gas dissolving into the liquid?

After reading about Henry's Law, I come to the conclusion that it shouldn't. Insight from this law tells me only that the amount of gas that dissolves into the liquid increases with an increase in partial pressure of the gas.

One approach I thought about is using the law of conservation of energy as my argument for why the system pressure should remain constant. The law states that the total energy of an isolated system remains constant. The gas under pressure can be defined by its kinetic energy (I suppose the liquid could be too?). So, if the gas is dissolved by the liquid, wouldn't the momentum transfer between the gas and liquid maintain the system pressure to be constant?

1. What processes take place once the seal is removed and the liquid and gas phase are hydraulically connected?
2. How is the final (equilibrium) pressure of the system calculated?

This question stems from a real issue I am trying to understand. The liquid is odorless mineral spirits and the gas is nitrogen (just a FYI). • I believe that you'll need to consider both the solubility of the gas in the liquid (you have) and the evaporation of the liquid into the gas. – user3823992 Feb 12 '15 at 1:57