Chemistry Lecture Notes

Introduction to Chemistry

• Definition: Chemistry is the study of matter.
• Matter: Anything that has mass and occupies space (has volume), can be weighed and studied.
• Historical Context:
  • Chemistry evolved from alchemy about 300 years ago.
  • Chemistry is involved in many historical developments (e.g., Bronze Age, medicine, fire, painting).
  • Daily life involves chemistry (e.g., brushing teeth, cooking, using electronic devices).

Branches of Chemistry

• Main Branches:
  • Organic Chemistry
  • Inorganic Chemistry
  • Physical Chemistry
  • Analytical Chemistry (developed last century)
  • Biochemistry
• Newer Branches: Nuclear Chemistry, Carbohydrate Chemistry, Protein Chemistry.
• General Chemistry Focus: Mostly inorganic and physical chemistry, with some analytical.

Scientific Method

• A systematic process used by scientists to ensure reliable science.
• Key Steps:
  1. Observation: Begin with noticing something of interest.
  2. Hypothesis: Develop a potential explanation.
  3. Experimentation: Design and conduct experiments to test the hypothesis.
     • Collect and verify data by repeating experiments.
     • Peer review through replication by others.
  4. Theory: Formulate a theory to explain the findings.
  5. Law: If the theory is repeatedly verified, it may become a scientific law.

Understanding Matter

• Definition: Matter has mass and volume.
• Phases of Matter:
  • Solid: Molecules are tightly packed.
  • Liquid: Molecules are close but not as tight as solids.
  • Gas: Molecules are far apart.

Classification of Matter

• Mixtures:
  • Homogeneous Mixtures: Uniform composition (e.g., air, solutions).
  • Heterogeneous Mixtures: Visible different components (e.g., salad).
• Substances:
  • Elements: Pure form, e.g., gold, iron.
  • Compounds: Chemical combination of elements.
• Separation: Mixtures can be separated physically; substances cannot.

Properties of Matter

• Physical Properties: Characteristics like color, electrical conductivity that don't alter the chemical identity.
• Chemical Properties: How a substance reacts with others (e.g., reactions with water, acid).
• Changes in Matter:
  • Physical Change: Reversible (e.g., melting, freezing).
  • Chemical Change: Irreversible, new substances formed (e.g., cooking an egg).

Data in Chemistry

• Types of Data:
  • Quantitative Data: Numerical measurements (e.g., mass, volume).
  • Qualitative Data: Descriptive data (e.g., color, phase).
• Properties:
  • Extensive Properties: Depend on the amount of matter (e.g., mass, volume).
  • Intensive Properties: Do not depend on the amount (e.g., boiling point, density).

Conclusion

• Overview of matter, phases, properties, and the scientific method.
• Understanding the basic classifications and properties is crucial before delving deeper into chemistry.