Classify each of the following properties as chemical or physical: (a) hardness of a diamond; (b) combustibility of gasoline; (c) corrosive character of an acid; (d) elasticity of a rubber band; (e) taste of chocolate.
The Correct Answer and Explanation is:
Correct Classification:
(a) Hardness of a diamond – Physical property
(b) Combustibility of gasoline – Chemical property
(c) Corrosive character of an acid – Chemical property
(d) Elasticity of a rubber band – Physical property
(e) Taste of chocolate – Physical property
Explanation
Physical properties describe characteristics of a substance that can be observed or measured without changing its chemical identity. These include features like color, melting point, density, boiling point, solubility, odor, hardness, and elasticity. In contrast, chemical properties involve the substance’s ability to undergo a change that alters its chemical structure. These properties include reactivity, combustibility, flammability, oxidation, and acidity.
In part (a), the hardness of a diamond refers to how resistant the material is to scratching or indentation. Since this property does not change the chemical identity of the diamond, it is physical in nature.
In part (b), the combustibility of gasoline describes its ability to burn in the presence of oxygen, producing new substances like carbon dioxide and water. This results in a chemical transformation, qualifying it as a chemical property.
In part (c), the corrosive character of an acid indicates how it reacts with metals or other substances, often producing hydrogen gas or altering the surface of materials. These interactions involve chemical reactions, making it a chemical property.
In part (d), the elasticity of a rubber band involves the physical ability of the material to stretch and return to its original shape. The chemical structure remains unchanged during stretching, so this property is physical.
In part (e), the taste of chocolate arises from its physical interaction with taste receptors. Tasting does not alter the chemical composition of chocolate itself; thus, taste is considered a physical property, even though it may involve complex molecular structures.
In summary, physical properties can be observed without altering a substance’s composition, while chemical properties are observed during a chemical change.
