Which of the following physical properties is typically unique for each pure substance and can be used to help identify it?

• A. Mass
• B. Volume
• C. Shape
• D. Melting point

Answer: (D)

Verified step by step guidance

1. Understand that physical properties are characteristics of a substance that can be observed or measured without changing its chemical identity.
2. Recognize that mass, volume, and shape are physical properties but are not unique to a pure substance because they can vary depending on the amount or form of the sample.
3. Learn that melting point is a physical property that is characteristic and unique for each pure substance because it occurs at a specific temperature under standard conditions.
4. Use the melting point as an identifying property because pure substances have a sharp and reproducible melting point, whereas mixtures melt over a range of temperatures.
5. Conclude that among the options given, melting point is the physical property typically unique to each pure substance and useful for identification.