Entropy is a measure of the randomness or disorder in a system. It is a thermodynamic quantity that describes the distribution of energy within a system.
In the context of gases, entropy refers to the degree of disorder or randomness of the gas molecules. This can be affected by factors such as pressure, temperature, and volume.
A change in entropy of a gas can be caused by a change in temperature, pressure, or volume of the gas. It can also be affected by chemical reactions or changes in the number or arrangement of gas molecules.
The SI unit for entropy is joules per kelvin (J/K). However, it can also be measured in other units such as calories per kelvin (cal/K) or joules per mole-kelvin (J/mol·K).
The second law of thermodynamics states that the total entropy of a closed system always increases over time. This means that the degree of disorder or randomness within a system will always tend to increase, leading to a higher overall entropy.