Intensive and Extensive Properties in Chemistry

Intensive and Extensive Properties

Introduction

In chemistry, properties of matter are classified as either intensive or extensive. Understanding these classifications helps in identifying and distinguishing substances based on their physical characteristics and behavior.

Intensive Properties

Definition and Characteristics

Intensive properties are those that are independent of the size or amount of substance present. These properties do not change regardless of how much material is present and are typically used to identify substances.

• Physical Properties: Intensive properties are characterized as physical properties.

• Examples:

  • Color

  • Density

  • Hardness

  • Boiling Point (bp), Melting Point (mp), Freezing Point (fp)

  • Temperature

  • Luster

Example Question: Which of the following are examples of intensive properties?

• Melting point

• Luster

Practice Question: Which of the following is not an example of an intensive property?

• Density (correct answer: density is actually an intensive property, but the question asks for the exception among the listed options)

• Elemental Magnetism

• Temperature

• Milligrams

• Freezing Point

Key Formula:

• Density: $\text{Density} = \frac{\text{Mass}}{\text{Volume}}$

Extensive Properties

Definition and Characteristics

Extensive properties are those that are dependent on the size or amount of substance present. These properties change when the quantity of material changes and are related to the total amount of matter.

• Physical Properties: Extensive properties are also characterized as physical properties.

• Examples:

  • Mass

  • Volume

  • Length

  • All forms of energy

Example Question: Which of the following is classified as an extensive property?

• Chemical Energy

Practice Question: Which of the following is not an example of an extensive property?

• Kilograms (correct answer: kilograms are an extensive property, but the question asks for the exception among the listed options)

• Gibbs Free Energy

• Milliliters

• Malleability

Practice Question: Which of the following is an extensive property of a nitrogen molecule?

• Boiling Point

• Temperature

• Moles

• Polarity

• Reactivity

Comparison Table: Intensive vs. Extensive Properties

Property Type	Definition	Examples
Intensive	Independent of amount of substance	Color, Density, Hardness, Boiling Point, Melting Point, Temperature, Luster
Extensive	Dependent on amount of substance	Mass, Volume, Length, Energy

Additional info:

• Intensive properties are useful for identifying substances because they remain constant regardless of sample size.

• Extensive properties are additive for the total system; for example, the total mass of a mixture is the sum of the masses of its components.