AQA GCSE Chemistry Paper 1 Overview

Content Overview:

• The video covers all topics in AQA GCSE Chemistry Paper 1 aimed at a Grade 9 standard.
• Includes sections on atomic structure, periodic table, chemical reactions, and more.
• Predicted papers and walkthroughs are available for practice.

Note-taking Strategy:

• Separate science content will be indicated.
• Watch at preferred speed but take notes and practice questions.

Atomic Structure

Definition of an Atom

• Smallest part of an element.
• Represented by a chemical symbol (e.g., O for Oxygen).

Size of an Atom

• Radius: ~0.1 nanometers (1 * 10^-10 m).
• Nucleus radius: less than 1/10,000 of the atom.*

Elements and Compounds

• Element: Substance made of one type of atom.
• Compound: Substance made of two or more elements chemically combined.
• Properties differ from constituent elements.

Separation of Compounds

• Can only be achieved through chemical reactions.
• Energy changes often involved.

Chemical Reactions

• Formation of new substances with energy changes.

Chemical Equations

Word and Symbol Equations

• Word equations: Water → Hydrogen + Oxygen.
• Symbol equations: H2O → H2 + O2 (must be balanced).

Balancing Equations

• Ensure equal numbers of each atom on both sides.
• Balance using coefficients (e.g., 2H2O → 2H2 + O2).

Common Formulas to Remember

• CO2, H2O, O2, H2, N2, NH3, HCl, H2SO4.

Subatomic Particles

Types of Particles

• Protons (+1 charge, mass = 1).
• Neutrons (0 charge, mass = 1).
• Electrons (-1 charge, very small mass).

Isotopes

• Atoms with same protons but different neutrons.

Ions

• Charged particles formed by loss/gain of electrons.

Electron Shells

Arrangement

• Electrons fill from inner to outer shells.
• 1st shell: 2 electrons, 2nd & 3rd shell: 8 electrons.

Periodic Table Representation

• Mass number = protons + neutrons.
• Atomic number = protons.

Mixtures and Separation Techniques

Mixtures

• Combination of elements/compounds not chemically combined.

Separation Methods

• Filtration, Crystallization, Distillation.
• Chromatography for colored compounds.

History of Atomic Model Development

Key Models and Discoveries

• Dalton’s solid sphere, Thomson’s Plum Pudding, Rutherford’s Nuclear model.
• Chadwick’s discovery of neutrons.

Periodic Table

Structure

• Groups (columns) and Periods (rows).
• Similar properties within groups.

Reactivity Series

• Metals vs. Non-metals.
• Group 0: Noble gases, unreactive.
• Group 1: Alkali metals, reactivity increases down the group.

Chemical Bonding

Types of Bonds

• Ionic (metal + non-metal), Covalent (non-metal), Metallic (metals).

Ionic Compounds

• Formed by electron transfer, electrostatic attraction.
• High melting/boiling points, conduct electricity in liquid form.

Covalent Compounds

• Shared electrons, form molecules (e.g., H2O, CO2).
• Low melting/boiling points, don’t conduct electricity.

Giant Covalent Structures

• Diamond, graphite (conducts electricity), silicon dioxide.

Metals and Alloys

Metal Structure

• Malleable, high melting points.

Alloys

• Mixture of metals, harder than pure metals.

Nanoparticles

Properties

• Large surface area to volume ratio.

Uses

• Medicine, Electronics, Catalysts.

Risks

• Can enter cells, catalyze harmful reactions.

Conservation of Mass and Calculations

Key Concepts

• Mass conserved in reactions.
• Relative formula mass and its calculations.
• Percentage composition by mass in compounds.

Moles and Calculations

• Avogadro’s constant (6.02 * 10^23).
• Calculating mass, moles, and concentrations.*

Chemical Reactions

Types of Reactions

• Oxidation, Reduction, Displacement.

Reactions with Acids

• Metal + Acid → Salt + Hydrogen.
• Neutralization reactions.

Making Salts

• From acids and bases.

Acids and Bases

Acids in Solution

• Produce H+ ions.

Bases

• Produce OH- ions.

pH Scale

• Measures acidity/alkalinity.

Titrations

• Used to find concentrations.

Electrolysis

Basics

• Splitting compounds using electricity.

Electrolysis of Solutions

• Products depend on reactivity and ions present.

Extraction of Metals

• Using electrolysis (e.g., aluminium).

Energy Changes

Exothermic vs Endothermic Reactions

• Exothermic: Energy released to surroundings.
• Endothermic: Energy absorbed from surroundings.

Bond Energies

• Calculating overall energy change in reactions.

Cells and Batteries

Chemical Cells

• Produce electricity using chemicals.

Fuel Cells

• Hydrogen fuel cells, advantages, and disadvantages.