Final answer:
To identify a substance that has the same density as another, color, melting point, and solubility can be used, as they are physical properties that can differentiate the substances without changing their identities.
Step-by-step explanation:
If two substances have the same density value, other properties must be used to distinguish them. These properties can include color, melting point, and solubility, among others. Each of these is a physical property that can be observed and measured without changing the substance's identity.
For instance, color can often give a clue about a substance's identity, especially if it is distinctive. The melting point is another crucial property that varies significantly among different substances and serves as an important identification factor. Finally, solubility, or the ability of a substance to dissolve in a particular solvent, can help differentiate between substances with similar density values.
A chemical property such as flammability could also be used; however, it requires observing a chemical reaction, which may change the substance's identity.