Which can be used to identify an unknown substance: mass, melting point density, volume, state of matter

Melting point

Density

Explanation:

The mass of any two substance can be same so we can distinguish between one Kg of two different substances based on masses.

The volume is again cannot determine the nature of substance.

Similarly with the state of matter we can rule out some possibilities but it cannot be used to identify the nature of a substance.

However melting point is characteristic of a substance. It can be used to identify the unknown substance. In fact in organic chemistry it is one of the property which helps us to determine the nature of compound.

Density can also be used to identify a compound.