Explain why density provides a more useful description of a meterial than does either mass or volume by itself

Answer 1

Density can be used to identify a material.
Mass only tells how much matter that you have. It does not decribe the matter.
Volume, the space matter takes up, also describes how muh but does nothing in telling what material.
elements and compounds have definite densities.

Answer 2

Because if you have different samples of the same material, they are all likely to have different masses and different volumes, even though they're all the same "stuff."

So, if I told you I have 2 kg of something, you don't know whether it's gold, wood, or whatever.

On the other hand, all the different samples of the material _will_ have the same _density_. The density of gold is 19.3 grams per cc, regardless of whether I have a 2kg sample, a 5kg sample, or whatever. Density is a characteristic of a _type_ of substance, while mass and volume (separately) are characteristics of a particular _sample_ of a substance.

So, if I told you I have something whose density is 19.3 grams/cc, you would know for sure that I don't have wood; and you might guess that I have gold.

Answer 3

Because density is an "intensive property". If you change the quantity, the density will still be the same.

Volume and mass are "extensive properties". If you change the quantity, the mass and volume will be different.