For this reason the amount of a substance is usually calculated from other measured quantities such as mass or volume. Chemists use both intensive properties, which are characteristic of a substance and independent of the amount of the substance, and extensive properties, which are characteristic of a substance and directly proportional to the amount of the substance. Temperature, pressure, and color are intensive properties while mass and volume are extensive properties. It is often useful to give an extensive property in a form which is not directly proportional to amount of substance. The operation of division of one extensive property by another extensive property has the effect of transforming the extensive property into an intensive property.
Density is an intensive property while both mass and volume are extensive properties.
Intensive properties are of greater interest to chemists because they are much more characteristic of the nature of a substance. Some extensive properties are transformed to intensive properties by dividing them by mass. Chemists usually prefer to transform extensive properties to intensive properties by dividing them by amount of substance. This division by amount of substance is usually indicated by preceding the name of the property with the word molar. Examples of properties transformed in this way include the molar mass, the molar volume, and the molar heat capacity.