# Entropy

Entropy is basically the measure of “disorder” in a system. It increases with every action and reaction. Entropy may be generated (or created), but it cannot be destroyed. Temperature and entropy are somewhat proportional. Entropy is measured in .

• Law of Thermodynamics: If two systems are in thermal equilibrium with a third system, then they must be in equilibrium with each other.
• Law of Thermodynamics: Heat and work are forms of energy transfer.
• Law of Thermodynamics: The entropy of any isolated system not in thermal equilibrium will increase.
• Law of Thermodynamics: Entropy approaches a constant value as temperature approaches absolute zero. (A pure crystal would have zero entropy).

Example: A man running on a day with temperature of 32°C and he loses 2.5 kg of perspiration. In this case, the latent heat of vaporization for perspiration is . Estimate the change in entropy of the water in order to vaporize the water.

Known:

Find:

• change in entropy (Δs)

Relevant equations:

Plug in numbers: