Pure Substances and Mixtures

Pure Substances

• Composed of a single type of matter or element.
• Have specific properties.
• Examples:
  • Water: Retains the same composition even when it changes state (e.g., freezing and melting).
  • Diamonds
• Physical Change:
  • The composition of pure substances remains unchanged during physical changes.
  • Example: Water turning into ice due to low temperatures is a physical change but the substance remains water.

Mixtures

• Combination of two or more pure substances.
• Two types of mixtures:

Homogeneous Mixtures

• Components are not visible to the eye.
• Examples:
  • Water with Salt
  • Chocolate Milk
  • Mayonnaise: Made from eggs, oil, and salt.
• Substances can exist in any state of matter: solid, liquid, or gas.

Heterogeneous Mixtures

• Components can be seen with the naked eye.
• Example:
  • Salad (tomato, lettuce, corn): Clearly visible components.

Practical Examples

• Chocolate Milkshake: A homogeneous mixture because its components are not visible.
• Water: A pure substance; remains the same in physical changes.
• Tomato, Lettuce, and Corn Salad: A heterogeneous mixture due to visible components.

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