Here's why:

* Characteristic properties are used to identify and distinguish different substances. They are intrinsic to the substance itself, meaning they don't change based on the amount of the substance present.

* Volume is the amount of space a substance occupies. It's a characteristic property because it's directly related to the size and density of the substance.

* Mass is the amount of matter in a substance. It's a characteristic property because it represents the inherent amount of "stuff" that makes up the substance.

What are NOT characteristic properties?

* Extensive properties are dependent on the amount of substance. For example:

* Volume can change if you have more or less of the substance.

* Mass can change if you have more or less of the substance.

* Length is another example of an extensive property.

Key takeaway:

While volume and mass can be extensive properties, they are also intrinsic properties that can be used to help identify a substance. They are characteristic properties because they are inherent to the substance itself and don't change based on how much of the substance you have.