Extensive Properties: Extensive properties are those that depend on the quantity of matter present in a system. These properties change when the amount of substance in the system is altered.
Examples:
- Mass
- Volume
- Energy
- Enthalpy
Intensive Properties: Intensive properties are independent of the amount of substance in the system. These properties remain constant, regardless of the quantity of matter.
Examples:
- Temperature
- Density
- Pressure
- Refractive index

The standard heat of formation, in kcal/mol, of $Ba^{2+}$ is:
Given: Standard heat of formation of SO₄²⁻(aq) = -216 kcal/mol, standard heat of crystallization of BaSO₄(s) = -4.5 kcal/mol, standard heat of formation of BaSO₄(s) = -349 kcal/mol.