Constant P

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Why is P deltaV insignificant when solids and liquids are involved?

[Erin Nagel 1G]

When you think of a system containing a solid or a liquid, it is very difficult for that system to increase or decrease in volume, so, in general, the volume of the system remains the same. Therefore, delta V is equal to zero. I think for PdeltaV to be insignificant, you also have to be considering a system at constant pressure, so, with no change in both pressure and volume, the entire thing is insignificant and basically zero.

[Julianne Morris 2C]

Yes! When a system contains a liquid or a solid, it is incredibly hard for there to be an increase or decrease in volume. Professor Lavelle gave an example in lecture today regarding a bottle of water. If we were to stand on the bottle of water (increase the pressure), it is very hard for the volume of that water to change without losing its concentration (the water bottle exploding). Therefore, the volume of these systems tends to remain the same. This mainly applies to solids and liquids, as gaseous states of matter can easily change shape and volume. Additionally, if either P=0 or Delta V=0, then the product of the two will be 0, rendering it insignificant.

[Ava Ward 1K]

Hey! So if there is constant pressure, delta P would be zero therefore making the equation for work equal zero. This is the same if the volume is constant because if either variable is zero, work would indefinitely be zero as well.

[Nicholas Flores 2F]

The change in the volume of liquids and solids is very minimal and insignificant. For example, when you stand on a table or a block of wood, the volume does not change significantly. The change in volume that does occur is so minimal that it can be ignored as it would be so small that it would not change anything. Solids and liquids are unlike gas which can expand to fill any container they are placed in. Solids and liquids have fixed volumes that cannot be changed unless mass is added or removed. For that reason, the change in volume (delta V) is 0 for solids and liquids because there will be no change in volume.

[SanthoshNandakumar3L]

Since changes in pressure and volume affect each other, do we assume that volume is also constant when it says "constant pressure?"

[Jarod Miller 2E]

Most of the time the volume of system with solids and liquids doesn’t change size because of the difficulty meaning that delta V would be equal to 0. If the system also has no change in pressure, then p delta v would also be 0 with the insignificance it has on the system.