Exergonic/Endergonic Expansion clarification

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Assume Adiabatic

If something increases in volume it is undergoing exergonic expansion because it is doing work on its surroundings; the change in temperature is negative because work is being done by the system

If someone is decreasing in volume it is undergoing endergonic expansion because the surroundings are doing work on it; the change in temperature is positive because work is being done on the system

Can someone confirm?

 

[jtran7]

you sure basically think temperature change as being equal to the change in internal energy.

DeltaU = deltaQ - deltaW

if you assume adiabatic situtation deltaQ would be zero. Then the only change in deltaU would be based on negative deltaW

if it is expanding deltaW is positive because P*deltaV = positive
therefore plugging it into the equation you get deltaU = 0 - (+W)

this results in a negative delta U would means a decrease in internal energy or decrease in temperature

 

[sps27]

you sure basically think temperature change as being equal to the change in internal energy.

DeltaU = deltaQ - deltaW

if you assume adiabatic situtation deltaQ would be zero. Then the only change in deltaU would be based on negative deltaW

if it is expanding deltaW is positive because P*deltaV = positive
therefore plugging it into the equation you get deltaU = 0 - (+W)

this results in a negative delta U would means a decrease in internal energy or decrease in temperature

What is exergonic, endergonic? Is it the same as exothermic, exothermic? I am guessing it is. I agree with what you have written.

Also, is it possible to have adiabatic isothermal expansion or contraction? I think it is possible. In that case, we will have change in internal energy but no change in temperature. Is that right?

 

[jtran7]

What is exergonic, endergonic? Is it the same as exothermic, exothermic? I am guessing it is. I agree with what you have written.

Also, is it possible to have adiabatic isothermal expansion or contraction? I think it is possible. In that case, we will have change in internal energy but no change in temperature. Is that right?

So this is the way i understand it...

Because you are referring to an adiabatic system Q is zero (no heat exchange)

For internal energy it changes based on Q and W

delta U = (Q) - (W)

change in internal energy can be seen as a representation of change in temperature

So if you have no change in temperature and no heat exchange it must mean that no work is being done so there can not be any expansion or contraction

So if you increase internal energy, molecules will have more energy and move quicker thus they will have a higher temperature. This can be achieved by either doing work on the system (-ve W, compression of the system) or by adding heat to the system (+ve Q)

ie delta U = (+Q) - (-W) resulting in positive U and hence increase in Temperature