Pressurized gas container gets opened

AI Thread Summary
The discussion revolves around calculating the temperature change when a pressurized 2-liter bottle containing air at 1105 mb is opened, leading to an adiabatic process. The user expresses confusion about how to approach the problem, particularly regarding the final volume and temperature after the pressure release. Key questions arise about whether to consider the bottle as a closed system or the air expanding into the environment, as well as the insulation of the bottle and the nature of the air flow. Clarification is sought on whether the temperature change refers to the air remaining in the bottle or the air that escapes. The conversation highlights the complexity of thermodynamic calculations in adiabatic processes.
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Homework Statement



I have an empty 2-Liter bottle. It contains 3 g of air inside with an initial air pressure of 1105 mb. When I open it (which is an adiabatic process), I release the pressure which is instantaneous. The pressure then becomes standard atmospheric pressure. What is the temperature change associated with
this?

Homework Equations


W = ∫pdV | dU = Q - W | du + pdV = dQ | dQ = cpΔU = -Wad

The Attempt at a Solution


To be honest, I really don't know where to begin. My attempts have only led me to equations that have 2 unknowns.
I had two basic trains of thought: We assume that opening the 2 liter bottle leads to a new volume of air that expands out into the environment. In which case, I don't know the final volume OR the final temperature.
My other train of thought was: We assume that the 2 liter bottle is a system and that 2 liter volume doesn't change. In which case the integral of work comes out as zero (as we are supposed to integrate from final to initial volume) and I don't know how to proceed with that either.
Any insight would help, this has been stumping me for a day and a half!
 
Physics news on Phys.org
Is that 1105 mb milli-bars or mega bars?

When you ask, "what is the temperature change," do you mean the temperature of the air remaining in the bottle after the system has equilibrated? The temperature of the air that has escaped and mixed with the room air? The room air temperature?

Is the bottle insulated?

Does the air flow through a valve, or is it flowing through an unblocked 2 liter bottle opening?
 
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