Chemistry Crash Course for Non-Science Background

Overview

• Introduction to basic chemistry concepts.
• Focus on theory, not GAMSAT-style questions.
• Important topics: reaction rates, equilibria, kinetic theory, Le Chatelier's Principle.

Lecture Outline

1. Mole Concept
2. Stoichiometry
3. Solids, Liquids, and Gases
4. Reaction Rates and Equilibria
5. Kinetic Theory
6. Le Chatelier's Principle
7. Rate Laws
8. Equilibrium Constants and Reaction Quotients

The Mole Concept

• Used to quantify large numbers of particles (atoms/molecules).
• 1 mole = 6.02 x 10^23 particles (Avogadro's number).
• Simplifies working with large numbers in chemistry (similar to kilometers vs. meters).

Stoichiometry

• Defined as the algebra of chemistry.
• Key Formula:
  • Mass Stoichiometry: ( n = \frac{m}{M} )
    • n = number of moles, m = mass in grams, M = molar mass in g/mol.
  • Volume Stoichiometry: ( n = C \cdot V )
    • C = concentration in moles/L, V = volume in liters.
  • Gas Law: ( PV = nRT )
    • P = pressure in kPa, V = volume in liters, n = moles, R = gas constant (8.31), T = temperature in Kelvin.
• Importance of mole as a link between different states and compounds.

Reaction Rates and Equilibria

• Rate of Reaction: Change in concentration over time (moles/L/s).
• Factors Influencing Rate:
  • Amount of reactants.
  • Temperature.
  • Volume (affects concentration).
  • Catalysts (lower activation energy).

Kinetic Theory

• Particles as moving entities requiring collision with sufficient energy for reaction.
• Activation energy as a critical concept.

Le Chatelier's Principle

• Describes how equilibrium shifts in response to changes in concentration, pressure, or temperature.
• Equilibrium: Forward and reverse reaction rates are equal.
• Changes analyzed through reaction quotient (Q) compared to equilibrium constant (K).
• Shifts:
  • Increase in concentration shifts equilibrium to the opposite side.
  • Pressure affects only gases, shifting towards fewer particles.
  • Temperature shift determined by endothermic/exothermic nature.

Rate Laws

• Mathematical representation of reaction rates.
• Rate Law: ( , \text{rate} = k[A]^x[B]^y , )
  • k = rate constant, A/B = reactants, x/y = orders determined experimentally.

Equilibrium Constants and Reaction Quotients

• Reaction Quotient (Q): Ratio of product/reactant concentrations.
• Equilibrium Constant (K): Q at equilibrium, indicates position of equilibrium.
• Comparing Q and K:
  • Q < K: Forward reaction favored.
  • Q > K: Reverse reaction favored.
  • Q = K: System at equilibrium.

Conclusion

• Understanding these concepts aids in quickly analyzing chemistry problems.
• Future topics to include organic chemistry and its applications.