What is the difference between the two sets of properties: (a) temperature, melting point, heat capacity, electrical conductivity and (b) density, molar volume - though both sets of properties are independent of the total mass of the substance and can be classified as intrinsic properties?
Answers
Answer:
Physical properties of materials and systems can often be categorized as being either intensive or extensive, according to how the property changes when the size (or extent) of the system changes. According to IUPAC, an intensive quantity is one whose magnitude is independent of the size of the system. whereas an extensive quantity is one whose magnitude is additive for subsystems. This reflects the corresponding mathematical ideas of mean and measure, respectively.
An intensive property is a bulk property, meaning that it is a local physical property of a system that does not depend on the system size or the amount of material in the system. Examples of intensive properties include temperature, T; refractive index, n; density, ρ; and hardness of an object, η.
By contrast, extensive properties such as the mass, volume and entropy of systems are additive for subsystems because they increase and decrease as they grow larger and smaller, respectively.
These two categories are not exhaustive since some physical properties are neither exclusively intensive nor extensive. For example, the electrical impedance of two subsystems is additive when — and only when — they are combined in series; whilst if they are combined in parallel, the resulting impedance is less than that of either subsystem.
The terms intensive and extensive quantities were introduced by Richard C. Tolman in 1917.