What this topic covers
Topic 3: Chemical changes has 2 subtopics:
- Reactions of acids
- Electrolysis
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GCSE Edexcel Higher Combined Science Chemistry · Topic 3 of 7
Topic 3: Chemical changes – GCSE Edexcel Higher Combined Science Chemistry revision notes
Choose a subtopic. Study acids, alkalis, salts, pH, and how electrolysis works. 22 lessons in 2 subtopics.
Revise Topic 3: Chemical changes for GCSE Edexcel Higher Combined Science Chemistry, including Reactions of acids. 22 lessons across 2 subtopics.
22
Lessons
2
Subtopics
Topic 3: Chemical changes lessons by subtopic
22 lessons, grouped by subtopic.
Reactions of acids
- Acid-Metal Reactions: Products and Patterns
- Redox in Acid-Metal Reactions
- What Salts Are Produced in Neutralisation?
- Neutralisation Reactions and Salt Formulae
- Making Soluble Salts from Acids
- Crystallising Salt Solutions and Making Pure Samples
- Understanding the pH Scale
- Acids, Alkalis and Neutralisation
- Introduction to Titrations
- Titration Calculations
- Understanding Acid Strength and Concentration
- pH Scale and Hydrogen Ion Concentration
- Core practical: pH change with calcium hydroxide and calcium oxide
- Core practical: preparing hydrated copper sulfate crystals
Electrolysis
- Understanding Electrolytes and Ion Movement
- Writing Half Equations for Electrolysis
- Products of Electrolysis in Molten Ionic Compounds
- Predicting Products in Aqueous Electrolysis
- Products at the Cathode and Anode
- Core practical: electrolysis of copper sulfate solution
- Understanding Electrode Reactions in Electrolysis
- Writing Half Equations for Electrode Reactions
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Frequently asked questions
What is Topic 3: Chemical changes?
Study acids, alkalis, salts, pH, and how electrolysis works. 22 lessons in 2 subtopics.
What is a base in chemistry?
A base is a substance that neutralises acids by accepting hydrogen ions. The Neutralisation Reactions and Salt Formulae notes cover this in full.
What is electrolysis?
Electrolysis is using an electric current to break down an ionic compound that is molten or dissolved. The Understanding Electrolytes and Ion Movement notes cover this in full.
What does pH stand for?
pH stands for potential of Hydrogen and relates to the concentration of hydrogen ions in solution. The Core practical: pH change with calcium hydroxide and calcium oxide notes cover this in full.
What is a titration?
A titration is a quantitative analytical technique where a solution of accurately known concentration is added to a solution of unknown concentration until the reaction between them is just complete. The Introduction to Titrations notes cover this in full.
What is an alkali?
An alkali is a soluble base that releases hydroxide ions (OH⁻) when dissolved in water. The Neutralisation Reactions and Salt Formulae notes cover this in full.
What colour change does methyl orange show?
Methyl orange is red in acid and yellow in alkali, with a sharp colour change at the end point. The Introduction to Titrations notes cover this in full.
What is an electrolyte?
An electrolyte is a liquid or solution that conducts electricity because it contains free-moving ions. The Understanding Electrolytes and Ion Movement notes cover this in full.
What colour change does phenolphthalein show?
Phenolphthalein is colourless in acid and pink in alkali. The Introduction to Titrations notes cover this in full.