Understanding the Isothermal Process: Temperature and Internal Energy Explained

[101nancyma]

Urgent!Isothermal process

Hi guys. i have a very short question. In an isothermal process, change is temperature is zero, so change in internal energy is zero, thus Q=W. The part that i am confused is that if Q=mc(deltaT) then should be a change in temperature in the isothermal process?
Thanks a lot

 

[bucher]

Q = mc(delta T) is not the correct equation in this example for the system. It has already been stated that Q must equal W in an isothermal process.

Think of it this way, if the system is a piston and the piston is drawn up then the system should cool. To keep the system at a constant temperature, the system is heated with the same energy that is extracted through work. Likewise, if the system is compressed then the system will have to expel heat to maintain its temperature.

If the system were in some kind of medium (air, water, etc) then the equation Q=mc(delta T) can be used for the surroundings.

Hope this helps.

 

[Count Iblis]

In an isothermal process, change is temperature is zero, so change in internal energy is zero

This isn't true in general either. It is true for an ideal gas, but in many other cases this is false. http://en.wikipedia.org/wiki/Intern...change_in_temperature_and_volume_or_pressure"

 

[101nancyma]

Q = mc(delta T) is not the correct equation in this example for the system. It has already been stated that Q must equal W in an isothermal process.

Think of it this way, if the system is a piston and the piston is drawn up then the system should cool. To keep the system at a constant temperature, the system is heated with the same energy that is extracted through work. Likewise, if the system is compressed then the system will have to expel heat to maintain its temperature.

If the system were in some kind of medium (air, water, etc) then the equation Q=mc(delta T) can be used for the surroundings.

Hope this helps.

I totally understand now..thanks alot