Using Ideal Gas Law in Energy Calculations

[Emma Kelly 3L]

Are there any conditions that have to be met so that we can use the ideal gas law in cases like this one from lecture? i.e. must pressure or volume be constant, can we only use it when the reaction is occurring within a certain type of system, etc.

[Anna Dai-Liu 3B]

I think it's just a theoretical construct that allows us to derive that equation by assuming there are no intermolecular interactions - but for most of the gases that we're dealing with, especially under standard conditions, I think it's safe to use that equation.

[Travis Wang 2G]

Like Anna said, I don't think we'll have a situation where the ideal gas law falls apart for this course. Dr. Lavelle is pretty quick to substitute deltan*RT for PdeltaV in that problem in part because the law holds up even in constant pressure like what the problem has.

[Morgan Oey-3H]

I'm pretty sure we can use the ideal gas law in any situation, and if there are times where pressure is constant, volume is constant, there are ways to replace values in the equations with others. For example, with internal energy, delta H - p delta V can replace Qp + w if there's constant pressure.

[Fiona H 2E]

In addition, just remember that the ideal gas law is used to calculate volume of gasses consumed or produced and used to interconvert between volumes and molar amount in chemical equations.