Physical Properties

Key Notes:

Definition:

Physical properties are characteristics of a substance that can be observed or measured without changing its chemical identity.

Types of Physical Properties:

• Intensive properties: These do not depend on the amount of substance, e.g., density, boiling point, color, hardness, and melting point.
• Extensive properties: These depend on the quantity of matter, e.g., mass, volume, and length.

Examples of Physical Properties:

• Color: The visual perception of the substance’s appearance.

• State of Matter: Whether a substance is solid, liquid, or gas.

• Melting Point: The temperature at which a solid changes into a liquid.

• Boiling Point: The temperature at which a liquid turns into a gas.

• Density: The mass per unit volume of a substance.

• Solubility: The ability of a substance to dissolve in a solvent.

• Conductivity: The ability to conduct heat or electricity.

Measuring Physical Properties:

• Mass: Measured using a balance (grams or kilograms).

• Volume: Measured using graduated cylinders, beakers, or formulas (liters or cubic centimeters).

• Temperature: Measured using a thermometer (Celsius, Fahrenheit, or Kelvin).

Importance of Physical Properties:

• Helps in identification of substances.
• Predicts behavior in different environments (e.g., knowing the boiling point helps in understanding phase changes).
• Plays a role in material selection for various applications.

Changes in Physical Properties:

• Physical changes affect physical properties (e.g., changes in state) but do not alter the chemical composition of the substance.

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