EK Chem Internal energy

[browncomputer]

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What does EK mean on page 54 of general chem when it says this, "For an ideal gas, any state function can be expressed as a function of temperature and volume only. For an ideal gas, internal energy is independent of volume and is a function of temperature only."

For instance, Pressure is a state function but it cannot be expressed as a function of temp and vol, right? you would need to know number of moles (P = nRT/V). or for entropy, you would need to know H or G. Please help me out, thanks!

 

[browncomputer]

anyone have an idea?

 

[DrknoSDN]

"For an ideal gas, any state function can be expressed as a function of temperature and volume only

A state function just means that it is path independent. No matter how you go from A>B>C>D or A>C>B>D, as long as the net is A>D you get the same result. Therefore can use PV=nRT and express the ideal gas behavior with only T and V always resulting in the same answer (path independent).

For an ideal gas, internal energy is independent of volume and is a function of temperature only."

This is saying that for an ideal gas, internal energy is directly proportional to the average molecular kinetic energy (temperature) and does not depend on other factors. It is basically saying ideal gases behave "normally", versus a real gas where factors like molecular size, collisions, and pressure can alter internal energy. (A real gas has a more complicated equation)

*That's just my interpretation without reading the whole page in context. GL

 

[browncomputer]

your interpretation really cleared up my confusion. thank you! that makes so much more sense.