Question

What are the physical properties of a substance?

Answer 1

Hint: Any characteristic or properties of a substance that can be determined without changing the chemical composition or identity of the substance are referred to as physical properties, whereas those characteristics or properties of a substance that can be determined only by changing the molecular structure of a substance are referred to as chemical properties.

Complete answer:
Physical properties are the characteristics of any substance that can be observed or measured without changing the identity of the substance.
The physical properties of any substance includes:
Melting point: Melting point is a temperature at which a substance changes its state from solid to liquid. A change of state occurs in melting point but it does not alter the identity of the substance hence it is considered as a physical property.
Boiling point: Boiling point is the temperature when the pressure exerted by the surrounding liquid is equal to the pressure exerted by the vapours of the liquid. Since the chemical composition of the substance remains the same, boiling point is also considered as a physical property.
Density: Density is defined as mass per unit volume. As, no reaction is involved for establishing the density of a substance, hence it is considered as a physical property.
Solubility: Solubility is the maximum amount of solute that can be dissolved in a known concentration of solvent. This property can be determined by simple observation; moreover it does not involve any change in the chemical composition of the substance, hence it is considered as a physical property.

Note:
Chemical properties are the characteristics of any substance that require a chemical reaction to occur. Chemical properties can be established by changing the chemical identity of the substance. Chemical properties also help to separate or purify unknown substances from other substances. Chemical properties involve flammability, toxicity, acidity, etc.