Physical Chemistry Fundamentals

Definition: Branch of chemistry that deals with the physical properties and behavior of chemical systems.
Key Concepts:
- Thermodynamics: Study of heat, energy, and work; laws of thermodynamics govern chemical reactions.
  - First Law: Energy cannot be created or destroyed.
  - Second Law: Entropy of an isolated system always increases.
- Kinetics: Study of reaction rates and the factors affecting them.
  - Rate laws and reaction mechanisms are crucial for understanding kinetics.
- Equilibrium: Condition where reactants and products are in a balanced state.
  - Le Chatelier's Principle: System at equilibrium responds to changes to counteract that change.
- Phase Equilibria: Study of the transitions between different states of matter (solid, liquid, gas).
  - Phase diagrams illustrate the conditions under which different phases exist.
- Spectroscopy: Interaction of electromagnetic radiation with matter.
  - Techniques include UV-Vis, IR, and NMR spectroscopy for analyzing chemical structures.

Definition: A theoretical construct that represents the number of electrons an atom can gain, lose, or share during a chemical reaction.
Rules for Assigning Oxidation Numbers:
1. Free Elements: Oxidation number is 0 (e.g., O2, N2).
2. Monatomic Ions: Equal to the charge of the ion (e.g., Na+ = +1, Cl- = -1).
3. Hydrogen: Typically +1 when bonded to nonmetals, -1 when bonded to metals.
4. Oxygen: Typically -2 in compounds, except in peroxides (-1) and when bonded to fluorine (+2).
5. Fluorine: Always -1 in compounds.
6. Alkali Metals: Always +1 in compounds.
7. Alkaline Earth Metals: Always +2 in compounds.
8. Sum of Oxidation Numbers: Must equal the overall charge of the molecule or ion.
Importance:
- Redox Reactions: Changes in oxidation numbers indicate oxidation (loss of electrons) and reduction (gain of electrons).
- Balancing Reactions: Helps in balancing chemical equations involving redox processes.
- Identification of Compounds: Determines the oxidation states of elements, aiding in understanding chemical behavior and reactivity.

Branch of chemistry focused on the physical properties and behaviors of chemical systems.
Thermodynamics:
- Examines heat, energy, and work in chemical reactions.
- Governed by laws that describe energy conservation and disorder in systems.
- First Law: Energy conservation principle; energy cannot be created or destroyed.
- Second Law: Entropy, or disorder, of an isolated system will always increase over time.
Kinetics:
- Investigates the rates of chemical reactions and the variables impacting those rates.
- Incorporates rate laws and reaction mechanisms to analyze and predict reaction behavior.
Equilibrium:
- A state where the concentrations of reactants and products remain constant over time.
- Le Chatelier's Principle describes how systems at equilibrium adjust to external changes in conditions.
Phase Equilibria:
- Studies transitions between solid, liquid, and gas phases.
- Phase diagrams highlight conditions such as temperature and pressure that determine phase existence.
Spectroscopy:
- Explores how matter interacts with electromagnetic radiation.
- Techniques such as UV-Vis, Infrared (IR), and Nuclear Magnetic Resonance (NMR) are used for structural analysis of chemicals.

A theoretical measure indicating the number of electrons an atom can gain, lose, or share during chemical reactions.
Rules for Assigning Oxidation Numbers:
- Free elements have an oxidation number of 0 (e.g., elemental O2 or N2).
- Monatomic ions possess an oxidation number equal to their charge (e.g., Na+ is +1, Cl- is -1).
- Hydrogen: Generally +1 when bonded to nonmetals; -1 when bonded to metals.
- Oxygen: Typically -2 in compounds, but -1 in peroxides and +2 when bonded to fluorine.
- Fluorine: Always has an oxidation number of -1 in compounds.
- Alkali metals consistently have an oxidation number of +1 in compounds.
- Alkaline earth metals always exhibit an oxidation number of +2 in compounds.
- The total of oxidation numbers in a molecule or ion must equal the overall charge.
Importance:
- Analyzing redox reactions: Changes in oxidation numbers highlight processes of oxidation (loss of electrons) and reduction (gain of electrons).
- Balancing chemical equations: Facilitates the balancing of redox reaction equations by considering oxidation states.
- Compound identification: Understanding oxidation states provides insights into the chemical behavior and reactivity of elements.