Is Temperature Intensive or Extensive Property? (And Why?)

Temperature is an intensive property because it remains constant regardless of the size or amount of the system. Intensive properties, such as temperature, pressure, and density, are independent of the system’s size and provide a measure of the system’s state at a specific point in space and time. ¹

Well, this was just a simple answer. But there are few more things to know about this topic which will make your concept super clear.

So let’s dive right into it.

Why is temperature an intensive property?

Temperature is considered an intensive property because it does not depend on the amount or size of the system under consideration. Intensive properties are characteristics of a substance or system that remain constant regardless of the quantity of the material present. They are independent of the system’s size or mass.

In contrast, extensive properties are dependent on the size or amount of the material and scale with the system’s size. For example, the mass, volume, and total energy of a substance are extensive properties.

Here’s why temperature is an intensive property:

• Size-independent: When you divide a system into smaller parts or combine multiple systems, the temperature of each part remains the same. For example, if you have a cup of hot water and pour half of it into another cup, both cups will have the same temperature. The temperature does not change with the quantity of water.
• Thermodynamic equilibrium: Intensive properties are closely related to thermodynamic equilibrium. When a system is in thermodynamic equilibrium, its intensive properties, including temperature, are uniform throughout the system. Temperature measures the average kinetic energy of particles in a substance. ² In equilibrium, the particles’ energies are evenly distributed, resulting in a uniform temperature.
• Independent of the system’s mass: Adding more material to a system will not alter its temperature. For instance, if you have 1 liter of water at a certain temperature and then add another liter of water at the same temperature, the resulting mixture will still have the same temperature.

In summary, temperature is an intensive property because it describes a characteristic that remains constant and uniform regardless of the size or amount of the material or system being observed.

Why is temperature not an extensive property?

Temperature is not an extensive property because it does not depend on the quantity or size of the material in a system. It is a property that remains unchanged when you change the amount of material present.

Here are additional reasons why temperature is not an extensive property:

1) Additive nature: 

Extensive properties, such as mass or volume, exhibit an additive nature. If you take two separate systems and combine them, the total value of an extensive property will be the sum of the individual values.

For example, if you have two containers of water, the total mass or volume after combining them will be the sum of the masses or volumes of the individual containers. However, temperature does not behave this way.

When you combine two systems, the resulting temperature is not the sum of the temperatures of the individual systems. Instead, the final temperature is determined by the thermodynamic equilibrium achieved between the two systems.

2) No proportionality to size: 

Extensive properties vary proportionally with the size or quantity of the material. If you double the amount of material in a system, the extensive property will also double. For instance, if you double the volume of a substance, its mass will double as well.

Temperature, on the other hand, does not follow this proportionality. Doubling the amount of a substance does not double its temperature. Temperature remains unchanged as long as the substance is at thermal equilibrium.

3) Independent of the shape of the system: 

The shape or geometry of a system should not affect its intensive properties. Temperature is independent of the shape of the system.

For example, a block of metal in the shape of a cube will have the same temperature as the same block of metal melted and poured into the shape of a sphere.

In summary, temperature is not an extensive property because it is independent of the quantity or size of the material in a system and does not exhibit the additive or proportional behavior that is characteristic of extensive properties.

Further reading

Is Color Intensive or Extensive Property?
Is Mass Intensive or Extensive Property?
Is Density Intensive or Extensive Property?
Is Hardness Intensive or Extensive Property?
Is HCl a Strong or Weak Acid?

1. Yan, C. Y. (n.d.). 1.3 Extensive and intensive properties – Introduction to Engineering Thermodynamics. 1.3 Extensive and Intensive Properties – Introduction to Engineering Thermodynamics. https://pressbooks.bccampus.ca/thermo1/chapter/extensive-and-intensive-properties/
2. Temperature & Energy | Energy Foundations for High School Chemistry. (n.d.). Temperature & Energy | Energy Foundations for High School Chemistry. https://highschoolenergy.acs.org/how-do-we-use-energy/temperature-energy.html