AQA A-Level Chemistry Lecture Summary

Overview

• This lecture covers the entire AQA A-level chemistry syllabus.
• Timestamps and additional learning resources are available in the description.
• This video serves as a brief revision guide, useful for pre-exam refreshment.
• Predictive papers, multiple-choice questions, and live review workshops are mentioned.

Atomic Structure

• Protons, Neutrons, Electrons: Protons/neutrons in nucleus, electrons in outer shells.
• Relative Charges: Protons (+1), Neutrons (0), Electrons (-1).
• Atom Diagram: Mostly empty space, nucleus diameter ~10^-15m, atom diameter ~10^-10m.
• Periodic Table: Mass number (larger), atomic number (smaller).
• Isotopes: Same atomic number, different mass number.
• Mass Spectrometry: Used to calculate relative atomic mass.

Electronic Structure

• Shells, Subshells, Orbitals: S, P, D, and F-block elements. Example: Calcium 1s² 2s² 2p⁶ 3s² 3p⁶ 4s².
• Ionic Configurations: Loss/gain of electrons for noble gas configuration.
• Ionization Energy: Energy required to remove an electron from an atom/ion.
• Trends: Across periods & between groups.

Chemical Calculations

• Significant Figures & Units: Consistent significant figures; unit conversions (cm³, dm³, m³).
• Moles: n = mass/Mr, Avogadro's number.
• Balancing Equations: Including state symbols.
• Ideal Gas Law: PV = nRT, Use of conversions for pressure, volume, temperature.
• Empirical & Molecular Formulas: Calculating ratios and actual numbers.
• Yield & Atom Economy: Calculating percentages, improving atom economy by alternative pathways or reusing waste products.
• Limiting Reagents: Determining reagents in excess.
• Water of Crystallisation: Hydrated vs. anhydrous salts, calculating moles of water.
• Uncertainty: Calculating percentage uncertainty.

Bonding and Structure

• Ionic Bonding: Metal and non-metal electron transfer, electrostatic difference.
• Covalent Bonding: Shared electron pairs.
• Metallic Bonding: Delocalized electrons in a metal lattice.
• Properties: Melting/boiling points, conductivity, solubility.
• Shapes of Molecules: Bond angles depending on electron pairs and lone pairs.
• Electronegativity: Trends, polar bonds.
• Intermolecular Forces: Induced dipoles, London forces, hydrogen bonding.

Periodicity

• Structure of the Periodic Table: Atomic number order, periodic trends (atomic radius, ionization energy).
• Groups 2 & 7: Reactivity trends, chemical reactions.
• Tests and Uses: For different group elements.

Instrumental Analysis

• Tests for Ions: Using barium chloride, silver nitrate etc.
• Mass Spectrometry: Ionization, acceleration, detection, analysis.
• Infrared Spectroscopy: Interpreting spectra for functional groups.
• NMR: Chemical shift and coupling for different types of spectroscopy.

Organic Chemistry

• Functional Groups & Naming: Alkanes, alkenes, alcohols, halogenoalkanes, aldehydes, ketones, etc.
• Isomerism: Structural, Geometric (EZ), Optical.
• Reactions: Addition, substitution, elimination.
• Synthesis: Multi-step processes.
• Polymers: Addition vs. condensation polymerisation, uses and properties.

Organic Synthesis and Analysis

• Acids, Esters, and Amides: Formation and hydrolysis reactions.
• Purification Techniques: Reflux, distillation, drying, and recrystallization.

Thermodynamics

• Enthalpy Changes: Formation, combustion, hydration.
• Bond Enthalpies: Calculations involving breaking/forming bonds.

Kinetics

• Rate of Reaction: Calculating rates from experimental data.
• Catalys: Homogeneous, heterogeneous, enzyme catalysis.

Equilibria

• Le Chatelier’s Principle: Effects of change in conditions.
• Equilibrium Constants (Kc, Kp): Calculations, effect of temperature.
• Acid-Base Equilibria: pH, strong/weak acids and bases, buffer solutions, titration curves.

Transition Metals

• Properties: Variable oxidation states, colored ions, catalysts.
• Complex Ions: Ligands, shapes, isomerism, stability constants.

Practical Skills

• Required Practicals: Techniques, calculations, accuracy, and error analysis.