In thermodynamics and chemistry, physical properties are divided into two categories based on how they change when the amount of matter changes. Here is the breakdown:
Extensive Properties
Definition: These properties depend on the amount of matter in a sample. If you add more of the substance, the value changes.
Think: "Extensive" sounds like "Extension" (size matters).
- Mass: More stuff equals more weight.
- Volume: Takes up more space.
- Enthalpy/Energy: A large fire produces more total heat than a match.
- Size: Length, width, etc.
Intensive Properties
Definition: These properties do not depend on the amount of matter. They are inherent to the identity of the substance.
Think: "Intensive" starts with "I" for "Independent."
- Temperature: A cup of boiling water is the same temp as a pot of boiling water.
- Density: Gold is always the same density regardless of the nugget size.
- Boiling Point: Water boils at 100°C whether it's a drop or an ocean.
- Color: Copper is reddish-brown regardless of shape.
The "Divide" Rule
A cool trick to remember: If you divide one extensive property by another, you often get an intensive property!
For example:
Mass (Extensive) / Volume (Extensive) = Density (Intensive)