IGCSE Edexcel Chemistry Lecture Notes

Introduction

• Covers 9-1 specification
• Offers revision guides at www.sciencewithhazel.co.uk

States of Matter

Solids

• Particles in fixed positions
• Vibrate with little kinetic energy
• Strong forces between particles

Liquids

• Particles more spaced
• Intermediate forces
• More vibration, no fixed positions

Gases

• Particles far apart
• High kinetic energy
• Weak forces between particles

State Changes

• Melting: Solid to liquid
• Freezing: Liquid to solid
• Boiling/Evaporating: Liquid to gas
• Condensation: Gas to liquid

Diffusion

• Movement from high to low concentration
• Passive process, no energy required
• Example: Diffusion of ammonia and hydrochloric acid

Solutions and Solubility

• Solute: Solid that dissolves
• Solvent: Liquid that dissolves solute
• Solution: Mixture of solute and solvent
• Saturated Solution: Maximum solute dissolved
• Solubility: Mass of solute in 100g of solvent

Atomic Structure and Periodicity

Basic Definitions

• Atom: Smallest particle
• Element: One type of atom
• Compound: Two or more elements chemically combined
• Mixture: Two or more elements not chemically combined
• Pure Substance: Only one type of material

Atomic Calculations

• Mass number = protons + neutrons
• Isotopes: Same protons, different neutrons

Separation Techniques

• Filtration: Insoluble solute from solvent
• Evaporation: Soluble solute from solvent
• Simple Distillation: Separates liquids with different boiling points
• Fractional Distillation: Separates mixtures like crude oil
• Chromatography: Separates liquids with different solubilities

Bonding

Ionic Bonding

• Between metals and non-metals
• Electrostatic attraction between oppositely charged ions

Covalent Bonding

• Between non-metals
• Shared pair of electrons

Chemical Structures

Giant Ionic Structures

• High melting/boiling points
• Conduct when molten

Giant Covalent Structures

• Diamond and Graphite
• Diamond: High melting point, no electricity
• Graphite: Conducts electricity

Simple Molecular Substances

• Low melting points

Giant Metallic Structures

• Conduct heat and electricity
• Malleable and ductile

Electrolysis

• Requires ionic compounds to be molten or in solution
• Electrodes made of inert material
• Anode attracts anions (positive), Cathode attracts cations (negative)

Group Chemistry

Group 1: Alkali Metals

• Highly reactive, especially with water

Group 7: Halogens

• Less reactive as you move down the group
• Displace less reactive halogens

Air and Oxygen

• Air composition: 21% oxygen, 78% nitrogen
• Oxygen reactions: Support combustion

Reactivity Series

• Lists metals from most to least reactive
• Determines how metals react with water and acids

Rusting and Corrosion

• Rusting requires water and oxygen
• Prevented by painting, oiling, or galvanizing

Extraction of Metals

• Iron: Blast furnace
• Aluminium: Electrolysis

Acids, Bases, and Salts

• Acids: Donate H+
• Bases: Accept H+
• Salt Formation: Metal replaces hydrogen in acid

Organic Chemistry

Alkanes

• Saturated hydrocarbons, single bonds
• General formula: CnH2n+2

Alkenes

• Unsaturated hydrocarbons, double bond
• General formula: CnH2n

Alcohols

• Functional group: -OH
• Uses: Fuels, solvents

Carboxylic Acids

• Functional group: -COOH

Polymers

Addition Polymerization

• Monomers like ethene form polymers

Condensation Polymerization

• Monomers react with loss of small molecule (e.g., water)

Energetics

Exothermic vs Endothermic

• Exothermic: Releases heat
• Endothermic: Absorbs heat

Rates of Reaction

• Influenced by temperature, concentration, surface area

Chemical Equilibrium

• Dynamic equilibrium in a closed system
• Effect of temperature and pressure on equilibrium position

Environmental Chemistry

• Effects of CO2 and greenhouse gases
• Acid rain formation

Conclusion

• Provides resources for further study and revision