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 Combined Science Chemistry · Topic 5 of 11
Topic 5: Energy changes – GCSE AQA Higher Combined Science 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 Combined Science Chemistry. 7 lessons in 2 subtopics.
Revise Topic 5: Energy changes for GCSE AQA Higher Combined Science Chemistry, including Exothermic and endothermic reactions. 7 lessons across 2 subtopics.
7
Lessons
2
Subtopics
Topic 5: Energy changes lessons by subtopic
7 lessons, grouped by subtopic.
Exothermic and endothermic reactions
- Understanding Exothermic and Endothermic Reactions
- Examples and Applications of Energy Transfer Reactions
- Breaking and Forming Bonds
- Calculating Energy Changes Using Bond Energies
- Explaining Exothermic and Endothermic Reactions
- Drawing and Understanding Reaction Profiles
- Activation Energy and Collision Theory
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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 Combined Science Chemistry. 7 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.
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.
What is the difference between exothermic and endothermic reactions?
An exothermic reaction transfers energy to the surroundings, so the temperature of the surroundings increases, while an endothermic reaction takes in energy from the surroundings, so the temperature of the surroundings decreases. The Understanding Exothermic and Endothermic Reactions notes cover this in full.