What this topic covers
Topic 5: Energy changes has 2 subtopics:
- Exothermic and endothermic reactions
- Chemical cells and fuel cells (chemistry only)
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GCSE AQA Higher Chemistry · Topic 5 of 11
Topic 5: Energy changes – GCSE AQA Higher Chemistry revision notes
Choose a subtopic. Topic 5: Energy changes covers Exothermic and endothermic reactions and Chemical cells and fuel cells (chemistry only) in GCSE AQA Higher Chemistry. 11 lessons in 2 subtopics.
Revise Topic 5: Energy changes for GCSE AQA Higher Chemistry, including Exothermic and endothermic reactions. 11 lessons across 2 subtopics.
11
Lessons
2
Subtopics
Topic 5: Energy changes lessons by subtopic
11 lessons, grouped by subtopic.
Exothermic and endothermic reactions
- Understanding Exothermic and Endothermic Reactions: Learn to distinguish between exothermic and endothermic reactions based on temperature changes and understand energy conservation in chemical reactions.
- Examples and Applications of Energy Transfer Reactions: Explore common examples of exothermic and endothermic reactions and evaluate their practical uses in everyday applications.
- Breaking and Forming Bonds: Learn how energy is involved in breaking bonds in reactants and forming bonds in products during chemical reactions.
- Calculating Energy Changes Using Bond Energies: Calculate overall energy changes in reactions by comparing the energy needed to break bonds with the energy released when new bonds form.
- Explaining Exothermic and Endothermic Reactions: Understand why reactions are exothermic or endothermic by comparing bond breaking and bond forming energies.
- Drawing and Understanding Reaction Profiles: Learn to draw simple reaction profiles for exothermic and endothermic reactions, showing reactant and product energy levels, activation energy, and overall energy change with curved reaction pathways.
- Activation Energy and Collision Theory: Understand what activation energy is, why particles need sufficient energy to react when they collide, and how to identify exothermic and endothermic reactions from reaction profiles.
Chemical cells and fuel cells (chemistry only)
- Introduction to Fuel Cells: Learn what fuel cells are, how they work by oxidising hydrogen electrochemically, and understand the overall reaction that produces water. Discover why fuel cells are considered as alternatives to traditional batteries.
- Comparing Fuel Cells with Batteries and Half Equations: Evaluate the advantages and disadvantages of hydrogen fuel cells compared to rechargeable cells and batteries. For Higher Tier students, learn to write the half equations for electrode reactions in hydrogen fuel cells.
- How Cells and Batteries Work: Understanding how chemical reactions in cells produce electricity, the factors that affect voltage, and how simple cells are constructed using different metals and electrolytes.
- Types of Cells and Batteries: Exploring the differences between rechargeable and non-rechargeable cells, how alkaline batteries work, and how rechargeable batteries can be restored by reversing chemical reactions.
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Frequently asked questions
What is Topic 5: Energy changes?
Topic 5: Energy changes covers Exothermic and endothermic reactions and Chemical cells and fuel cells (chemistry only) in GCSE AQA Higher Chemistry. 11 lessons in 2 subtopics.
What are examples of endothermic reactions?
Examples of endothermic reactions include thermal decomposition, such as calcium carbonate breaking down into calcium oxide and carbon dioxide, and citric acid reacting with sodium hydrogencarbonate. The Examples and Applications of Energy Transfer Reactions notes cover this in full.
What does an exothermic reaction profile look like?
In an exothermic reaction profile, the products are at a lower energy level than the reactants, because energy is released to the surroundings. The Drawing and Understanding Reaction Profiles notes cover this in full.
What is combustion?
Combustion is the reaction of a fuel with oxygen that releases energy as heat and light. The Examples and Applications of Energy Transfer Reactions notes cover this in full.
What is activation energy?
Activation energy is the minimum amount of energy that particles must have to react when they collide, measured in kJ/mol. The Activation Energy and Collision Theory notes cover this in full.
What are examples of exothermic reactions?
Examples of exothermic reactions include the combustion of fuels such as methane, oxidation reactions such as iron rusting, and neutralisation of acids and bases. The Examples and Applications of Energy Transfer Reactions notes cover this in full.
What does an endothermic reaction profile look like?
In an endothermic reaction profile, the products are at a higher energy level than the reactants, because energy is absorbed from the surroundings. The Drawing and Understanding Reaction Profiles notes cover this in full.
What is an electrode?
An electrode is a conductor through which electricity enters or leaves an electrolyte during chemical reactions. The How Cells and Batteries Work notes cover this in full.
How do hand warmers work?
Many hand warmers use the slow oxidation of iron powder by oxygen from the air, 4Fe + 3O₂ → 2Fe₂O₃, which releases heat for hours. The Examples and Applications of Energy Transfer Reactions notes cover this in full.