A new quantity - Entropy
Degree of “disorder” in a system.
Zero entropy at 0K
Absolute scale – not just increments like ∆H
Depends on temperature and solution.
Gases most, then liquids, then solids
Simple substances – low entropy values
Not zero for elements – depends on temperature
Different entropy values for same chemical
e.g. CO2 as solid or gas,
Water as solid, liquid or gas