Which characteristic of a substance is considered a chemical property?
A its boiling point
B its reactivity
C its density
D its conductivity
The correct answer and explanation is:
The correct answer is B. its reactivity.
A chemical property of a substance refers to its ability to undergo a chemical change or reaction when interacting with other substances. Reactivity is a key example of a chemical property because it involves the substance’s ability to combine with or transform into other substances. Reactivity is not something that can be directly observed without altering the substance itself. For example, a substance’s reactivity may describe how it reacts with oxygen (oxidation), acids, or other chemicals, potentially resulting in a new substance.
The other options listed are examples of physical properties, not chemical ones:
- A. its boiling point: This is a physical property. It describes the temperature at which a substance changes from liquid to gas. The boiling point is related to the energy required for the molecules of the substance to overcome intermolecular forces.
- C. its density: Density is a physical property that describes the mass of a substance per unit volume. It is calculated by dividing the mass of the substance by its volume and is not related to the substance’s ability to undergo a chemical change.
- D. its conductivity: Conductivity is also a physical property, referring to a material’s ability to conduct electricity or heat. It is determined by the physical structure of the substance, such as the presence of free electrons in metals or the arrangement of molecules in insulating materials.
In summary, reactivity is the only option among the choices that qualifies as a chemical property because it refers to how a substance interacts with other substances, often resulting in a transformation or change in composition. This is fundamentally different from a physical property, which only involves characteristics that can be observed or measured without changing the substance’s chemical structure.