In summary: Overall, entropy plays a crucial role in understanding and predicting the behavior of thermodynamic systems and chemical reactions.
jambaugh
Gold Member
Introduction
The student of thermodynamics, as they consider pistons and ideal gasses and such, often begin to grasp the nature of entropy only to find as they delve deeper that grasp slips away.  In the deeper analysis of thermodynamic systems via statistical mechanics this grasp may slip away entirely.
“How can my cup of hot tea, have a given entropy from instant to the instant when at any given instant it is in some exact physical state whether I know which one it is or not?” “If entropy is a measure of disorder then what makes one state more ordered than another?  By what divine aesthetic is order measured?”
One begins to think entropy is merely an on-paper quantity describing only an aspect the probability distributions of various states of reality.  But, when a sip of that hot tea burns the tongue the immediately physical nature of entropy becomes very hard to deny.
Thermodynamics and Entropy
Joule’s...

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Chestermiller and Greg Bernhardt
I think it would be helpful to expand the section on How Entropy is Used. Its practical uses are much more significant than in understanding heat and work. Its major use is in chemical thermodynamics to allow us to quantify interphase chemical equilibrium of multicomponent systems (distillation, absorption, adsorption, crystallization, liquid-liquid extraction, etc.) and also in quantifying the equilibrium constant for chemical reactions.

anorlunda, dRic2 and jambaugh

## 1. What is thermodynamics?

Thermodynamics is a branch of physics that deals with the study of the relationship between heat and other forms of energy, and how it affects matter.

## 2. What is entropy?

Entropy is a measure of the disorder or randomness in a system. It is a fundamental concept in thermodynamics and is often referred to as the "arrow of time" as it describes the direction in which a system tends to evolve.

## 3. How are thermodynamics and entropy related?

Thermodynamics and entropy are closely related as entropy is a key concept in thermodynamics. The second law of thermodynamics states that the total entropy of an isolated system will tend to increase over time, indicating that the system is becoming more disordered.

## 4. Why is thermodynamics important?

Thermodynamics is important because it helps us understand and predict how energy is transformed and transferred in various systems. It has applications in fields such as engineering, chemistry, and biology.

## 5. How does entropy affect the world around us?

Entropy plays a crucial role in our everyday lives. It is the reason why things tend to break down, why we age, and why it is easier to make a mess than to clean it up. Entropy also plays a role in many natural processes, such as the water cycle and the formation of stars.

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