Why is density referred to as a characteristic property of matter?

Answer : Density of any particular matter remains the same at any concentration at any weight.

Density does not varies with the concentration. The formula for density is mass / volume.

So if the mass changes the density will change accordingly, also if the volume changes the density will get changed.

because, of the above reasons density is referred as a characteristic property of matter.

vanderwaal's forces of attraction are the electrostatic intermolecular forces that exist in a molecule due to the temporary or permanent dipoles that are developed in a molecule. in , the major intermolecular forces are dipole-dipole interactions as the molecule is polar (bent structure). so the vanderwaal's forces of interaction in between molecules are the permanent dipole-dipole interactions that develop due to the dipole that exists in between the polar h - s bond. the positively charged hydrogen atom is attracted towards the negative end of the dipole that is sulfur of the adjacent molecule. therefore, these forces of attraction are relatively stronger than that of london dispersion forces that exist in non polar molecules.