Chemistry Lecture: Classifying Matter

Introduction

• Chapter 1 starts with the concept of matter.
• Focus: Definitions and classifications of matter.
• These concepts may be tricky in multiple-choice questions.

Key Concepts of Matter

Matter

• Everything is made up of matter: Pure substances and Mixtures.

Pure Substances

• Definition: Composed of only one type of atom or molecule.
• Types:
  • Elements: Simplest form, cannot be broken down further (e.g., Iron (Fe), Silver (Ag)).
  • Compounds: Composed of two or more elements but considered a pure substance because it's only elements (e.g., NaCl).
    • Ionic Compounds: Metal and non-metal (e.g., NaCl: Sodium (Na) and Chlorine (Cl)).
    • Covalent Compounds: Only non-metals (e.g., CO2, Carbon Dioxide).

Mixtures

• Definition: Composed of two or more different types of atoms or molecules.
• Types:
  • Homogeneous Mixture: Uniform composition, appears as one single phase (e.g., Black coffee).
  • Heterogeneous Mixture: Non-uniform composition, distinct layers or parts (e.g., Wet sand).

Practice Classification

Pure Substances

• Iron: Element.
• Carbon Monoxide (CO): Pure substance (Compound).

Mixtures

• Wet sand: Heterogeneous mixture.
• Orange Juice: Homogeneous mixture (assuming no pulp).
• Tea with sugar: Homogeneous mixture (sugar dissolves).
• Air: Homogeneous mixture (uniform gases).
• Blood: Heterogeneous mixture (plasma and blood cells).

Tips to Determine Mixture Types

• Look for descriptive factors or adjectives.
• Consider examples like air with smog (heterogeneous) or coffee with creamer (heterogeneous if layers are visible).

Additional Practice

1. Picture Analyses:
   • First Picture:
     • Pure substance
     • Element
   • Second Picture:
     • Mixture
     • Heterogeneous (layers visible)
   • Third Picture:
     • Homogeneous mixture (uniformly mixed)
   • Fourth Picture:
     • Compound

Conclusion

• For more help, visit Melissa Maribel's website.
• Continue practicing identification and classification of matter.