Thermodynamics | Basic Of Thermodynamics

 Basic Of Thermodynamics

Introduction to Thermodynamics:

Thermodynamics is that branch of physics that is concerned with the relationships of heat, work, and energy. It further describes how energy transforms from one form to another and the laws governing such transformations. This interesting field has played a crucial role in understanding natural processes, as well as technology: in both engine and refrigeration technologies.

What is Thermodynamics?

Thermo plus Dynamic has its origins from the Greek words "Thermo," meaning “Heat”, and "Dynamic," meaning “Power”. In short, it is the science of how heat, which, as we'll see later is a form of energy, is converted into work and vice versa. Energy is an inherent constituent of any process, and thermodynamics gives us tools to understand how energy transformations might become efficient and limited.

Key Concepts in Thermodynamics:

With that said, let's move on to laws of thermodynamics, beginning with some definitional basics:

System and Surroundings: The system is simply the part of the universe we're examining; everything else is the surroundings. Systems can be either isolated, closed, or open depending on if they exchange energy or matter with their surroundings.

Heat: This type of energy transferred between systems or objects at different temperatures.

Work: Energy transferred by a force applied through a distance.

Internal Energy: Sum total of energies in a system. It can hold kinetic as well as potential energy.

Branches of Thermodynamics:

1. Classical Thermodynamics

This section involves macro systems and the heat-work energy relation but excludes the activities of individual atoms and molecules. This section applies laws of thermodynamics to understand the systems at very large scales.

2. Statistical Thermodynamics

This chapter applies the principles of statistics and probability theory to relate the microscopically determined properties of atoms and molecules to the macroscopically observable behavior of materials. It gives an additional developed meaning for entropy, temperature, and energy.

3. Chemical Thermodynamics

In chemical thermodynamics, the focus is on the effect that changes in heat and energy have on chemical reaction. Such concepts as Gibbs free energy and enthalpy are important in predicting whether reactions will go spontaneously.

4. Equilibrium and Non-Equilibrium Thermodynamics

Equilibrium Thermodynamics: Deals with systems that are balanced and at equilibrium, wherein there is no energy transfer.

Non-Equilibrium Thermodynamics: It is a study of systems with active energy transfer; it provides knowledge on dynamic processes, which include Heat Flow, Diffusion, and Chemical Reactions.

Thermodynamic System:

A thermodynamic system is the matter or energy located within an identified boundary and is under examination about how heat, work, and internal energies relate to one another. There are physical or imaginary boundaries which distinguish the surroundings from the system, depending on the manner by which matter and energy are allowed to transfer between the two.

These systems form a basis for behavior in the sciences of engineering, physics, and chemistry, ranging from the functioning of heat engines to biological organisms.

Types of Thermodynamic Systems:

There are three main kinds of thermodynamic systems that distinguish themselves based on what they exchange with their surroundings in terms of energy and matter.

1. Open System 

An open system when it exchanges both energy and matter with its surroundings. This system is dynamic because, as you would expect from the name, mass like air, water, or other fluids crosses over the boundary, along with energy like heat or work.

Example of an Open System:

A car engine is an example of open system. Fuel and air go into the engine. Combustion takes place and produces heat and work while exhaust gases are expelled from the system. In this whole process, both energy and matter are exchanged amongst the system and its surroundings.

Open systems occur mainly in nature and industries in which material and energy inputs are required for continuation of activities.

2. Closed System

A closed system can transfer energy, either as heat or work, to the surroundings but does not transfer any matter. The boundary of a closed system allows energy to pass across the boundary but the mass within the system is preserved.

Example of a Closed System:

A closed system is a sealed steam engine, which runs on its own cycle. Since the engine undergoes an exchange of heat energy with the surroundings, it shares the same quantity of working fluid (steam or water) inside the engine both at its beginning and end.

Closed systems are primarily utilized in engineering fields to study energy transfers mainly when the material content within a system needs to be controlled.

3. Isolated System

in isolated system does not exchange either matter or energy with its surroundings. Such systems are few in practice but have their uses as idealized concepts in thermodynamics.

Example of an Isolated System:

The universe can be assumed to be an isolated system because nothing within the universe interacts with anything outside through any kind of energy or matter exchange. On a smaller scale, quasi-insulated thermoses are constructed to mimic an ideal isolated system, that is theoretically, no heat exchange takes place.

Isolated systems are used as a reference for more practical real-word systems in theoretical analysis, and the knowledge of how energy conservation works in the former will make for an easy interpretation.

Thermodynamic Processes Within Systems:

Besides the classification of systems, there are some other crucial concepts in thermodynamic processes about how energy and matter behave under different conditions. Some of the most common types of thermodynamic processes are below:

1. Isothermal Process

It is an isothermal process in which the temperature of the system remains constant. In this process, any heat added to the system is totally used for work and internal energy is unchanged.

For example: Compression or expansion of gas in a piston where the temperature remains constant.

2. Adiabatic Process

there is no heat exchange between the system and its surroundings. All changes in energy result from work done on or by the system.

For example: The rapid compression or expansion of gas in an insulated container.

3. Isobaric Process

An isobaric process occurs at a constant pressure. This means that any amount of heat added or removed from the system would cause the change in volume but does not change the pressure.

For example: Heating water in an open pot when the atmospheric pressure is constant.

4. Isochoric Process

An isochoric process, or an isovolumetric one, occurs at a constant volume. As the volume does not vary, any amount of heat added to the system would elevate the pressure.

For example: Heat a gas in an enclosed rigid container.

Conclusion:

It is seen that thermodynamics is one of the fundamental branches of physics that tell about the modes of energy transfer and transformation between different systems. With its laws and concepts, we explain how heat, work and energy behave in natural processes and in the engineered systems, like engines and refrigerators. Thermodynamics helps improve energy usage efficiency but also provides insights in terms of nature and technology. Mastering the principles of thermodynamics enables us to further acquire a better and more sustainable future in terms of energy resources.