Thermodynamics, the Power of Heat

Thermodynamics-Thermodynamics processes

The term heat was not discovered as a form of energy till the year 1798; Sir Benjamin Thompson, who was a British military engineer, discovered that an infinite amount of heat could be generated while loading barrels of the cannons and that the heat that was generated is directly proportional to the work done. 

Sir Benjamin’s discovery about the relationship shared between the heat generated and the amount of work done is an essential concept in thermodynamics. Later in that same century, Sir Rudolf Clausius, a German mathematician and scientist, successfully elaborated the concepts of thermodynamics into the first and second laws of thermodynamics, respectively. 

This module here is an introduction and brief about the very common topic in Physics called Thermodynamics.

What do you mean by thermodynamics?

The term ‘Thermodynamics’ in Physics and various other subjects means the study related to the flow or transfer of heat from one body to another.

We can define ‘Thermodynamics’ by saying that thermodynamics is that branch in the field of Physics which manages and is related to the changes in energy levels that assist in a chemical reaction.

The science of the link between energy, temperature, work and heat is thermodynamics. In general, thermodynamics is related to the displacement of energy from a body to another body and from one form to another form. The basic idea of ‘Thermodynamics’ is a type of energy that belongs to a particular measure of mechanical effort.

Various elements of thermodynamics

1. System

• Open system
• Closed system
• Isolated system

2. Surroundings

What is a System?

A ‘System’ in thermodynamics is defined as a region or matter present in space that is bounded by an arbitrary surface for study purposes. In simple words, a system is defined as a collection of matter that is contained in space surrounded by walls containing specified permeabilities that separate it from the surroundings.

What is Surrounding?

A ‘Surrounding’ in thermodynamics is the region located outside the system around the boundary that separates the system and surroundings.

Physical properties of a system are thermodynamics

There are two properties of a system in thermodynamics-

Intensive property

The intensive properties of a System in Thermodynamics is a property of the system that does not depend on the stretch of the system. It means that the intensive properties in Thermodynamic Systems are not related to the mass. Examples of intensive properties- density, specific heat, refractive index, surface tension, viscosity, pressure, temperature, etc.

Extensive property

The extensive properties of a System in Thermodynamics is a property of the system that depends on the stretch of the system. It means that the extensive properties in Thermodynamic Systems are related to the mass. They share a relationship of direct proportionality. Examples of extensive properties- entropy, heat capacity, energy, mass, volume, etc.

Thermodynamic processes

A process is Thermodynamic if there is a change in the system or body from one macroscopic property of equilibrium to another macroscopic property of equilibrium.

There are various Thermodynamic Processes, like:

• Irreversible Process

• Reversible Process

• Isochoric Process

• Isobaric Process

• Adiabatic Process

• Isothermal Process

Laws of thermodynamics

Although thermodynamics grew fast throughout the nineteenth century in response to the need to boost the effectiveness of steam engines, the rules of thermodynamics are so broad that they apply to all physical and biological systems. The rules of thermodynamics, in particular, provide a full explanation of all the changes in any system’s energy state and its ability to do beneficial work on its surroundings.

First law of thermodynamics

The First Law of Thermodynamics is the law of conservation of energy. Sir stated it. Meyer and Sir. Helmholtz in the year 1840.

The first law of thermodynamics tells us that energy can neither be created nor destroyed, but it can be successfully transformed from one form to another. It can also be explained as the total amount of energy present in the universe is always constant.

Second Law of thermodynamics

Heat does not spontaneously move from a colder region to a warmer region and heat cannot be completely converted into work at a particular temperature. The second law of thermodynamics states that the universe’s entropy does not change for any reversible processes, and the entropy increases for a spontaneous process.

∆Suniverse = ∆Ssystem + ∆surroundings > 0

In this law, S = entropy and

∆Stotal > 0 is irreversible.

∆Stotal = 0 is reversible and in equilibrium.

∆Stotal < 0 is non-spontaneous.

Third law of thermodynamics

At absolute zero (0 Kelvin), the temperature freezes to exist; that is, there is no translation, rotation or vibration at this temperature.

The third law of thermodynamics states that the entropy of a pure crystalline substance at absolute zero is always 0.

Conclusion

Thermodynamics is considered as the mathematical examination of energy relationships. It is also considered a scientific discipline concerning a study that refers to heat and temperature and their relationship with work and energy. It deals with the macroscopic properties of a system instead of the constituents of microscopy.

This module will help us know about the basics and various concepts about Thermodynamics Processes and Types of Thermodynamic Processes.

A student who wishes to professionalise in the field of Chemistry must know all about the details of this topic and thus, help students in the examination and various other competitive examinations.