Work of expansion

[Sophia_Francis_1G]

Are work of expansion problems only applicable to situations involving pistons and displacing a certain volume against the pressure of the atmosphere? In what other context could these problems be used?

[Daniel Kozlov 1G]

While work of expansion can exist outside of a system like a piston, since something as simple as burning firewood does work of expansion on the gas around it, I yet to see a problem that asks us to work with such a system. The reason the piston works so well for most problems is because it is a closed system, while something like a burning fire would be an open system and would require us to consider matter entering and leaving the system, making calculations rather difficult. In regards to other closed systems we might see, I would think that larger versions of gas in a piston could potentially come up, such as using expanding vapor in a steam engine or combustion in a car engine. These are where I could see problems about these types of system going, but otherwise I think we would have to wait to see what other topics we end up covering in class and how we can use these new concepts to enhance our ability to calculate the work of expansion in other systems.