Ideal gas law as approximation

[Ashley Johnson 2G]

What does it mean in outline 1 when it says "identify reactions where the ideal gas law can be used as an approximation?" Are there specific reactions where this law is an approximation and others where it is not?

[Cass Cheng 2A]

I think it means the conditions under which the ideal gas law can be used, meaning when gases behave "ideally." So this means when gases are at low pressures and high temperature conditions. If they deviate from these "ideal" conditions, the ideal gas law cannot be used. Under low temperatures and high pressure, the intermolecular forces and molecular sizes become important and are no longer negligible, so the ideal gas law won't work.

[Kloey Reyes]

In the real world, gases never behave completely ideally, but they come especially close when pressure is low and temperature is high. This is because these conditions make the gases further from condensing into liquid or freezing into a solid. I'd assume reactions that have these conditions would be where you could use the ideal gas law as an approximation and those that do not have these conditions would be where you wouldn't use the law as an approximation.

[Guadalupe_3B]

I believe this means that they would like you to use the ideal gas law to describe the behavior of a gas or predict the behavior of real gasses.

[Ainsley DeMuth 1H]

Dr Lavelle used the ideal gas law in one of his most recent lecture videos (lecture 11) in thermodynamics so I believe that would be the best example to reference in regards to this question. In the example in the lecture video, we were able to establish that the delta H-P(delta V) equation was not usable because there were too many unknowns. However, because there was a constant external pressure (an open beaker was sued), we were able to substitute the ideal gas law into the equation.