Chemistry Foundations - Condensed Notes

Matter and Chemistry

• Matter: Anything with mass and volume.

• Chemistry: Study of matter, its composition, and processes.

Classification of Matter

• Pure Substance: Fixed composition.

  • Elements: Same atoms, cannot be broken down (e.g., Carbon (C)).

  • Compounds: Two or more elements, broken down chemically (e.g., $BaCl_2$).

• Mixture: Combination of substances retaining individual properties.

  • Heterogeneous: Non-uniform (e.g., Salad).

  • Homogeneous: Uniform (e.g., Windex).

Mixtures

• Heterogeneous Mixtures:

  • Suspensions: Large particles that settle (e.g., Sandy Water).

  • Colloids: Medium particles, cloudy, don't settle (e.g., Fog).

• Homogeneous Mixtures:

  • Solutions: Very small particles (e.g., Kool-Aid).

  • Alloys: Solid metal mixtures (e.g., Brass).

Tyndall Effect

• Used to differentiate homogeneous from heterogeneous mixtures based on particle size.

• Positive Tyndall Effect: Light beam visible (Colloids, Suspensions).

• Negative Tyndall Effect: No visible beam (Solutions).

Separation Methods

• Physical (mixtures):

  • Filtration, Evaporation, Boiling, Sorting, Distillation, Centrifugation

• Chemical (compounds):

  • Chromatography, Electrolysis, Extraction

Properties of Matter

• Intensive: Independent of amount (e.g., Density, Color).

• Extensive: Depends on amount (e.g., Mass, Volume).

• Physical Property: Observed without changing substance identity (e.g., Boiling Point).

• Chemical Property: Ability to change into a new substance (e.g., Flammability).

Changes in Matter

• Physical Change: No change in identity (e.g., Melting).

• Chemical Change: New substance formed (e.g., Burning).

Key Properties

• Density is a Physical and Intensive property.