# THERMODYNAMICS: Calculating maximum heat required...?

Exactly 2.000 moles of He(g), an ideal gas, initially occupies a volume of 12.50 L at a temperature of 26.85 0C. If the gas is to be expanded isothermally to a final volume of 25.00 L, what is the maximum amount of heat that would need to be supplied to the gas?

There it is. I am not sure what MAXIMUM heat means? Is that heat from work on the boundary? I'm not quite sure what to do... other than use some application of the first law i believe.

I need a good explanation for future problems etc. Not someone spitting an answer. I want process not the calculated value please.

Update:

Exactly 2.000 moles of He(g), an ideal gas, initially occupies a volume of 12.50 L at a temperature of 26.85 0C. If the gas is to be expanded isothermally to a final volume of 25.00 L, what is the maximum amount of heat that would need to be supplied to the gas?

There it is. I am not sure what MAXIMUM heat means? Is that heat from work on the boundary? I'm not quite sure what to do... other than use some application of the first law i believe.

I need a good explanation for future problems etc. Not someone spitting an answer. I want process not the calculated value please.

ADDITIONAL DETAILS: I dont know how to respond to that answer without adding it here... STP as in standard temp and pressure? no based on the question. I dont know what SLC means. Thanks!

Update 2:

ahhhh. It says it acts as an ideal gas... I would assume I am expected to calculate the pressure at some point in the answer using the ideal gas law.

Update 3:

Sorry dude that doesnt help at all. This is a college 209 thermodynamics class... I'm guessing you're not at this level.

Relevance

Maybe just us PV=nRT where R=8.31

P×12.5=2×8.31×299.85K

From that we can work out that the pressure is 398.6kPa

If we then replace the volume 12.5L with 25L it becomes

T=PV/nR

therefore T=398.6×25/2*8.31

The new temperature is 599.5788207K

I dont really know if that help. My chemistry has become crap cause i havent done it in a while . Maybe i'm not up to that level but thats all i could do :P

hope it helps a bit :P

Source(s): woops, i'm still in high school :P