Entropy: Joules per Kelvin Explained

In summary, entropy is a measure of the number of specific ways in which a system may be arranged, but the units of joules per kelvin may not make intuitive sense. The Boltzmann constant can be used to convert it to a dimensionless value. The interpretation of entropy as "disorder" is misleading, and there are more resources available on this topic. The units of joules per kelvin follow from the second law of thermodynamics, and in this case, energy and temperature represent the change of entropy, with energy being the heat transferred into the system and temperature being the absolute temperature of the system before the transfer.
  • #1
Saado
44
0
Whilst I understand that entropy is a measure of the number of specific ways in which a system may be arranged. The units for entropy don't make sense to me intuitively. Why joules per kelvin? What way at all does that show how "disordered" a system is. When I hear joules per kelvin, I think of energy/average thermal energy.

What does the energy and temperature represent in this case?
 
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  • #2
You can transform it to a dimensionless value with the Boltzmann constant. And that is just a unit conversion factor.
 
  • #3
Saado said:
What way at all does that show how "disordered" a system is.
Here is a nice video on why the "disorder" interpretation of entropy is misleading:



More links in the video description on youtube.
 
  • #4
Why joules per kelvin?
It follows from the second law of thermodynamics.
What does the energy and temperature represent in this case?
It is the change of entropy. In this case, energy is the heat transferred into the system and temperature is the absolute temperature (in Kelvin) the system at.
 
  • #5
td21 said:
Why joules per kelvin?
It follows from the second law of thermodynamics.
What does the energy and temperature represent in this case?
It is the change of entropy. In this case, energy is the heat transferred into the system and temperature is the absolute temperature (in Kelvin) the system at.

So the temperature is the absolute temperature before the heat energy is transferred into the system?
 

What is entropy?

Entropy is a measure of the amount of disorder or randomness in a system.

What is the unit for entropy?

The unit for entropy is joules per kelvin (J/K).

How is entropy related to temperature?

Entropy is directly proportional to temperature, meaning that as temperature increases, so does entropy.

What does it mean for entropy to increase?

An increase in entropy means that there is more disorder or randomness in a system.

How does entropy relate to the second law of thermodynamics?

The second law of thermodynamics states that the total entropy of a closed system will always increase over time. This means that the amount of disorder or randomness in a system will always increase, leading to a decrease in the system's available energy.

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