Four properties of a substance that can be used to identify it are:
1. Chemical Composition: The specific arrangement and types of atoms in a substance, as determined by its chemical formula.
2. Melting Point and Boiling Point: The temperature at which a substance changes from a solid to a liquid (melting point) and from a liquid to a gas (boiling point) is characteristic of that substance.
3. Density: The mass of a substance per unit volume, which is unique to each material.
4. Solubility: How readily a substance dissolves in a particular solvent or under certain conditions, which can vary between substances.
These properties, among others, help scientists and researchers identify and classify different substances.