Energetics
Energy-change workflows spanning calorimetry, Hess cycles, bond/lattice enthalpy, and Gibbs feasibility framing.
This route helps when you keep missing the same type of question across different topics. Use it to combine lesson notes with linked practice and tools in one place.
Notes and Hubs in This Route
- Alkane Reactions
Explain methane combustion and UV chlorine substitution, balance combustion equations, and use products to identify incomplete combustion.
- Hydrogen as a Fuel and Fuel Cells
Learn why hydrogen is a potential fuel, how a hydrogen fuel cell generates electricity directly, and how production affects its environmental impact.
- Biofuels and Carbon Emissions
Explain sugarcane bioethanol as a renewable fuel, follow carbon through its production and combustion, and evaluate emissions across its life cycle.
- Bond Breaking and Bond Forming
Explain qualitatively why reactions are exothermic or endothermic by comparing energy absorbed in bond breaking with energy released in bond making.
- Calculating Heat from Molar Enthalpy (Optional)
Optional enrichment: scale a supplied molar enthalpy, distinguish signed heat from energy released, and use the balanced equation’s reacting amount.
- Carbon Cycle
Trace carbon transfers between atmospheric carbon dioxide, living material and fuels.
- Comparing covalent structures
Compare small molecules, poly(ethene) chains and giant covalent networks. Use bonds, forces and mobile charge carriers to explain their properties.
- Covalent bonding and electron diagrams
Count shared and lone electron pairs, draw dot-and-cross diagrams, and deduce single, double and triple covalent bonds.
- Endothermic Reactions
Endothermic reactions: definition, ΔH is positive, and how to interpret energy profile diagrams and activation energy in exam questions.
- Energy Changes in Chemical Reactions
K324 and 6092 energy changes hub: enthalpy, energy profiles, and qualitative bond-breaking and bond-making explanations.
- Exothermic Reactions
Exothermic reactions: definition, ΔH is negative, and how to interpret energy profile diagrams and activation energy without common traps.
- Fossil Fuels: Combustion and Emissions
Explain non-renewable fossil fuels, balance methane combustion, and connect oxygen supply and fuel composition to emissions.
- Introduction to Energy Changes
Follow heat between the reacting system and its surroundings, distinguish exothermic and endothermic changes, and use the sign of ΔH.
- Ionic bonding: forming ions and balancing charges
Form ions by electron loss and gain, show sodium chloride and magnesium chloride with dot-and-cross diagrams, and balance charges to write formulas.
- Ionic structures and properties
Use the giant lattice and ion mobility to explain high melting temperatures and the electrical conductivity of solid, molten and dissolved ionic compounds.
- Giant covalent structures: diamond, graphite and silica
Explain the hardness, conductivity and heat resistance of diamond, graphite and silicon dioxide using their giant covalent structures.
- Molecular structures and properties
Distinguish bonds within molecules from attractions between molecules, and use structure to explain melting, boiling and electrical behaviour.
- Reading and Drawing Energy Profiles
Read and draw exothermic and endothermic profiles, distinguish activation energy from enthalpy change, and add a catalysed pathway with the same endpoints.
- Changes of state and heating curves
Changes of state: melting, boiling, freezing, condensation and sublimation, plus interpreting heating/cooling curves using particle theory.
- Activation Energy and Boltzmann Distribution (A Level)
Use collision theory to explain temperature effects on rate via the Boltzmann distribution and the fraction of particles with E ≥ Ea.
- Chemiluminescence Explained: Why Some Reactions Glow
Chemiluminescence is light produced directly by a chemical reaction. Learn how glow sticks work, why colours change, and where the technique is used.
- Batteries and Fuel Cells (A Level)
Compare primary vs secondary cells, write key half-equations, and understand the hydrogen–oxygen fuel cell as a practical electrochemical system.
- Bond Enthalpy Calculations (A Level)
Estimate reaction enthalpy using average bond enthalpies (ΔH ≈ Σ bonds broken − Σ bonds formed), with sign conventions and exam pitfalls.
- Calorimetry (q = mcΔT) (A Level)
Perform calorimetry calculations using q = mcΔT, then convert to ΔH per mole with correct signs, units, and heat-loss corrections.
- Catalysis and Enzymes (A Level)
Compare homogeneous vs heterogeneous catalysis, explain how catalysts lower Ea, and describe enzymes as specific catalysts with temperature/pH effects.
- Cell Potentials and Spontaneity (A Level)
Calculate E°cell, predict electron flow direction, and connect the sign of E°cell to feasibility under standard conditions.
- ΔG = −nFE (A Level)
Link electrode potentials to energetics using ΔG° = −nFE°cell, and connect feasibility, electron count, and cell voltage in one chain.
- Energetics & Thermodynamics (A Level)
A Level energetics and thermodynamics notes: calorimetry, Hess and Born–Haber cycles, lattice energy, entropy, and Gibbs free energy (ΔG) reasoning.
- Enthalpy Changes and Energy Profiles (A Level)
Use energy profile diagrams to interpret ΔH and activation energy, and write correct exothermic/endothermic explanations.
- Entropy and Gibbs Free Energy (A Level)
Predict entropy change and use ΔG° = ΔH° − TΔS° to decide feasibility, with careful signs, units, and data-booklet cues.
- Hess’ Law and Cycles (A Level)
Use Hess’ law to build enthalpy cycles and calculate unknown ΔH values from formation/combustion data, with clean sign/multiple handling.
- Lattice Energy and Born–Haber Cycles (A Level)
Define lattice energy, predict trends with ionic charge/radius, and use Born–Haber cycles to connect lattice energy to formation enthalpy.
- Standard Electrode Potentials and the SHE (A Level)
Define standard electrode potential (E°), understand standard conditions, and use the standard hydrogen electrode (SHE) as the reference half-cell.
- Bioluminescence: How Living Things Make Light
Bioluminescence is chemistry inside living organisms. Learn the luciferin–luciferase reaction and why so many ocean species glow.
- The Chemistry of Fireworks: Colour, Light, and Bangs
Fireworks are controlled combustion. Learn how oxidisers, fuels, and metal salts create colour, light, and sound.