The first law of thermodynamics

The first law of thermodynamics, also known as the law of energy conservation, states that energy cannot be created or destroyed in an isolated system. Instead, it can only change forms or be transferred from one part of the system to another or between the system and its surroundings.

Mathematically, the first law of thermodynamics can be expressed as:

$\mathrm{\Delta }𝑈=𝑄-𝑊$

Where:

• $\mathrm{\Delta }𝑈$ is the change in internal energy of the system.
• $𝑄$ is the heat added to the system from its surroundings.
• $𝑊$ is the work done by the system on its surroundings.

This equation means that any change in the internal energy of a system must be accounted for by the heat added to the system and the work done by the system on its surroundings, according to the principle of energy conservation.

In other words, energy can be converted from one form to another (such as from heat to work or vice versa), but the total amount of energy in the system remains constant.

The first law of thermodynamics is fundamental in understanding and analyzing various physical processes, including chemical reactions, heat transfer, and mechanical work. It forms the basis for the study of thermodynamics and plays a crucial role in engineering, physics, chemistry, and other scientific disciplines.