Please check if my understandings of these terms are right because they are a bit confusing to me.
For all three types of expansions, a change in volume means work is done by the system to the surrounding.
Isobaric expansion: As $p = F/A$ applies to the force of piston over area. The system is in isobaric equilibrium as long as the force does not change. In order for volume to increase, heat must enters the system to increase internal energy, leading to increase in volume.
Isothermal expansion: takes in heat from a heat reservoir, convert that heat into work energy and the system expands in volume. As temperature must remain constant, the heat energy absorbed is converted into work energy instead of internal energy. (But if heat is converted to internal energy, wouldn't the system increase in volume as well?)
Adiabatic expansion: As $Q= 0$, work should be constant. In this case, isn't volume will remain constant as well so no expansion will take place?
Best Answer
Yes quite! The ideal gas law (and in general any state equation) holds only on equillibrium while the 1st law (and all the rest) hold in general. So, your anslysis mr James Hoyland is inacurrate.
Mr Steven, the post includes the word "expansion" so volume changes by assumption.
And mr or ms PhysC, the first two cases are correct. About the third, expansion would occur by pulling the piston thus removing energy from the system and causing decrease on temperature