Source: https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/6-1-3-required-practical-effect-of-concentration

[Revision notes](https://senecalearning.com/en-gb/revision-notes.md) › [GCSE](https://senecalearning.com/en-gb/revision-notes/gcse.md) › [Chemistry](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry.md) › [AQA](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa.md) › [Higher](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher.md) › Required Practical: Effect of Concentration

# Required Practical: Effect of Concentration

Chemistry: AQA GCSE Higher, topic 6.1.3

## Effect of Concentration on the Rate of Reaction (Gas Volume Method)

This experiment aims to investigate how altering the concentration of a solution influences the rate at which a gas is produced during a chemical reaction.

### Apparatus and materials

![Apparatus and materials](https://image-v2.cdn.app.senecalearning.com/2020-05/1c17e4fa-d9cd-4893-a420-dad93f86490b/syringe-.jpg)

- Magnesium ribbon (cut into equal lengths)
- Sulfuric acid solutions of different concentrations (e.g. 1.0 mol/dm3 and 1.5 mol/dm3)
- 100 cm3 conical flask
- Gas syringe with delivery tube
- Rubber bung
- Stop clock
- Measuring cylinder
- Safety goggles and a lab coat

### Variables

![Variables](https://image-v2.cdn.app.senecalearning.com/2018-11/1e11d522-97a8-45bd-ab24-5f992ae04617/-magnesium-element-.jpg)

- Independent variable: 
 - Concentration of the acid
- Dependent variable: 
 - Volume of gas produced over time
- Control variables:
 - Length and surface area of magnesium ribbon
 - Volume of acid used
 - Temperature
 - Use of the same equipment setup for all trials

### Method

![Method](https://image-v2.cdn.app.senecalearning.com/2025-10/8507d859-0c2c-4b95-ace4-8f0f6aa7d2a0/syringe.png)

- Set up the apparatus.
- Measure a fixed volume of dilute sulfuric acid and pour it into the conical flask.
- Add one strip of magnesium ribbon to the acid and quickly seal the flask with the bung.
- Start the stop clock as soon as the magnesium is added.
- Record the volume of hydrogen gas collected in the syringe every 10 seconds until no more gas is produced.
- Repeat the procedure using a different concentration of acid.

### Analysis

![Analysis](https://image-v2.cdn.app.senecalearning.com/2018-08/9334053b-c336-42b8-b58c-1f1299e12494/Graph-.jpg)

- Record time (s) and gas volume (cm3) in a results table.
- Plot a graph of gas volume against time for each acid concentration.
- Compare the gradients (slopes):
 - The steeper the line, the faster the rate of reaction.
- To calculate the mean rate of reaction = 
$$\dfrac{Total Mass Of Gas Produced (cm^3)}{Reaction Time (s)}$$

### Expected Results

![Expected Results](https://image-v2.cdn.app.senecalearning.com/2018-03/e6bc4370-606d-4110-a40a-0bbffa99267b/Making%20chemicals.jpg)

- Higher acid concentrations will produce hydrogen gas more quickly.
- The same total volume of gas may be produced, but in less time.
 - This supports the hypothesis that a higher concentration increases the rate of reaction.

### Hazards and precautions

![Hazards and precautions](https://image-v2.cdn.app.senecalearning.com/2019-05/35dbff6f-0c75-431d-9d41-cbaa992380c5/sharon-mccutcheon-523212-unsplash-min.jpg)

- Dilute sulfuric acid:
 - Acid may irritate the skin and eyes
 - Wear goggles and rinse immediately if contact occurs
- Reaction mixture fizzing:
 - May cause acid spray or foam to escape
 - Use a conical flask and avoid leaning over the mixture
- Hydrogen gas:
 - Flammable if exposed to sparks or flame
 - Ensure there are no open flames nearby

## Investigating the Rate of Reaction (Colour Change Method)

There are many ways to carry out this practical. This experiment investigates how temperature affects the rate of a chemical reaction by observing the rate at which a solution changes colour.

### Apparatus and materials

![Apparatus and materials](https://image-v2.cdn.app.senecalearning.com/2025-10/8ca3b11b-b357-43d9-87cf-15c76fa79550/bb.png)

- Measuring cylinders
- Conical flask 
- Stop clock
- Sheet of white paper with a black cross drawn on it
- Bunsen burner or hot water bath (to adjust temperature)
- Thermometer
- Solution of choice
- Dilute acid of choice

### Variables

![Variables](https://image-v2.cdn.app.senecalearning.com/2018-09/04beade3-c039-4a0f-a7e7-15e86c7e0c83/test-tube-experiment=solution-inject.jpg)

- Independent variable:
 - Temperature of the sodium thiosulfate solution
- Dependent variable:
 - Time taken for the cross to become invisible
- Control variables:
 - Concentration and volume of both solutions
 - The same black cross and viewing method
 - Same observer for consistency

### Method

![Method](https://image-v2.cdn.app.senecalearning.com/2025-10/e7da22ec-a359-4bb0-88e6-c4f4f28bf537/cloud.png)

- This reaction uses sodium thiosulfate and hydrochloric acid.
- Pour 50 cm3 of sodium thiosulfate solution into a conical flask.
- Place the flask on top of a piece of white paper with a black cross drawn in the centre.
- Measure 10 cm3 of dilute hydrochloric acid in a separate cylinder.
- Add the acid to the flask, swirl, and start the clock.

### Method (continuation)

![Method (continuation)](https://image-v2.cdn.app.senecalearning.com/2025-10/67c5308f-ecee-417b-a69d-faa66a8491e6/cloud.png)

- Observe the solution and note the time when the cross can no longer be seen.
- Record the temperature of the reaction mixture.
- Repeat the experiment at different starting temperatures:
 - 20°C, 30°C, 40°C, 50°C

### Analysis

![Analysis](https://image-v2.cdn.app.senecalearning.com/2018-04/20150740-311b-403b-8161-6add1596ca22/desmos-graph%20(31).png)

- Calculate 1000 ÷ time (s) for each temperature to estimate the reaction rate.
- Plot a graph of:
 - Rate of reaction (1/s) on the y-axis
 - Temperature (°C) on the x-axis
- Draw a smooth curve of best fit.
- The line should show that higher temperatures lead to faster reactions due to more energetic particle collisions.

### Explanation

![Explanation](https://image-v2.cdn.app.senecalearning.com/2018-12/f76f12f7-e6ef-4e5a-b089-985645c5cdc9/liquid-particle-model-exam-examphysics-.png)

- When temperature increases, particles move more quickly and collide more often with enough energy to react.
 - This means the reaction occurs faster, and the sulfur precipitate forms in a shorter time.

## Test yourself on Required Practical: Effect of Concentration

- What should be done immediately after adding the magnesium ribbon to the acid?
- What does a steeper gradient on a graph of gas volume against time show about the reaction?
- Using the formula for mean rate of reaction, what happens to the calculated rate if the same volume of gas is produced in less time?
- A graph of gas volume against time shows two lines for different acid concentrations. One line has a much steeper gradient than the other. Which trial most likely used the higher concentration of acid?
- A student compares two trials using different concentrations of sulfuric acid, but the same length of magnesium ribbon in each. Based on the expected results, what should be true about the total volume of gas produced in each trial?

[Practise this topic for free](https://app.senecalearning.com/classroom/course/e39e7f70-d100-11e7-9b85-bbf8589a9044/section/9c348d04-e39b-4298-b267-c71055997344/session)

- Previous topic: [6.1.2 Plotting Reaction Rates](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/6-1-2-plotting-reaction-rates.md)
- Next topic: [6.1.4 Collision Theory](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/6-1-4-collision-theory.md)

## Chemistry: AQA GCSE Higher contents

### 1 Atomic Structure
- 1.1 Atoms & Elements
  - [1.1.1 Elements & Compounds](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/1-1-1-elements-and-compounds.md)
  - [1.1.2 Chemical Formula](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/1-1-2-chemical-formula.md)
  - [1.1.3 Chemical Reactions](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/1-1-3-chemical-reactions.md)
  - [1.1.4 Chemical Equations](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/1-1-4-chemical-equations.md)
  - [1.1.5 Mixtures](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/1-1-5-mixtures.md)
  - [1.1.6 Separating Mixtures](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/1-1-6-separating-mixtures.md)
  - [1.1.7 Separating Mixtures 2](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/1-1-7-separating-mixtures-2.md)
  - [1.1.8 Model of the Atom](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/1-1-8-model-of-the-atom.md)
  - [1.1.9 Sub-Atomic Particles](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/1-1-9-sub-atomic-particles.md)
  - [1.1.10 Atom Size](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/1-1-10-atom-size.md)
  - [1.1.11 Atomic Number](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/1-1-11-atomic-number.md)
  - [1.1.12 Atomic Number - Calculations](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/1-1-12-atomic-number-calculations.md)
  - [1.1.13 Isotopes](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/1-1-13-isotopes.md)
  - [1.1.14 Isotopes HyperLearning](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/1-1-14-isotopes-hyperlearning.md)
  - [1.1.15 Isotopes - Calculations](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/1-1-15-isotopes-calculations.md)
  - [1.1.16 Relative Atomic Mass](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/1-1-16-relative-atomic-mass.md)
  - [1.1.17 Electron Structure](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/1-1-17-electron-structure.md)
  - [1.1.18 Periodic Table](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/1-1-18-periodic-table.md)
  - [1.1.19 The History of the Periodic Table](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/1-1-19-the-history-of-the-periodic-table.md)
  - [1.1.20 Metals & Non-Metals](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/1-1-20-metals-and-non-metals.md)
  - [1.1.21 Noble Gases](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/1-1-21-noble-gases.md)
  - [1.1.22 Displacement Reaction](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/1-1-22-displacement-reaction.md)
  - [1.1.23 Halogens](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/1-1-23-halogens.md)
  - [1.1.24 Alkali Metals](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/1-1-24-alkali-metals.md)
  - [1.1.25 Alkali Metals - Properties](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/1-1-25-alkali-metals-properties.md)
  - [1.1.26 Transition Metals](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/1-1-26-transition-metals.md)
  - [1.1.27 Transition Metals - Special Properties](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/1-1-27-transition-metals-special-properties.md)
  - [1.1.28 End of Topic Test - Atomic Structure](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/1-1-28-end-of-topic-test-atomic-structure.md)
  - [1.1.29 Grade 9 - Atoms & Elements](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/1-1-29-grade-9-atoms-and-elements.md)
  - [1.1.30 Exam-Style Questions - Atomic Structure](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/1-1-30-exam-style-questions-atomic-structure.md)
  - [1.1.31 Application Questions - Atomic Structure](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/1-1-31-application-questions-atomic-structure.md)
  - [1.1.32 Diagnostic Misconceptions - Balancing Equations](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/1-1-32-diagnostic-misconceptions-balancing-equations.md)
  - [1.1.33 Diagnostic Misconceptions - Isotopes](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/1-1-33-diagnostic-misconceptions-isotopes.md)

### 2 Chemical Bonding
- 2.1 Chemical Bonds
  - [2.1.1 Types of Bonds](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/2-1-1-types-of-bonds.md)
  - [2.1.2 Ions](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/2-1-2-ions.md)
  - [2.1.3 Ionic Bonds](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/2-1-3-ionic-bonds.md)
  - [2.1.4 Ionic Compounds](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/2-1-4-ionic-compounds.md)
  - [2.1.5 Empirical Formulae](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/2-1-5-empirical-formulae.md)
  - [2.1.6 Covalent Bonds](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/2-1-6-covalent-bonds.md)
  - [2.1.7 Metallic Bonds](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/2-1-7-metallic-bonds.md)
  - [2.1.8 Covalent Bond Examples](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/2-1-8-covalent-bond-examples.md)
  - [2.1.9 Representing Covalent Bonds](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/2-1-9-representing-covalent-bonds.md)
  - [2.1.10 Dots-And-Cross Diagrams](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/2-1-10-dots-and-cross-diagrams.md)
  - [2.1.11 Dots-And-Cross Diagrams 2](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/2-1-11-dots-and-cross-diagrams-2.md)
  - [2.1.12 Exam-Style Questions - Chemical Bonds](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/2-1-12-exam-style-questions-chemical-bonds.md)
- 2.2 States of Matter
  - [2.2.1 States of Matter](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/2-2-1-states-of-matter.md)
  - [2.2.2 Simple Sphere](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/2-2-2-simple-sphere.md)
  - [2.2.3 Changing State](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/2-2-3-changing-state.md)
  - [2.2.4 Changing State 2](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/2-2-4-changing-state-2.md)
  - [2.2.5 Changing State HyperLearning](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/2-2-5-changing-state-hyperlearning.md)
  - [2.2.6 State Symbols](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/2-2-6-state-symbols.md)
  - [2.2.7 Exam-Style Questions - States of Matter](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/2-2-7-exam-style-questions-states-of-matter.md)
  - [2.2.8 Diagnostic Misconceptions - Particles](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/2-2-8-diagnostic-misconceptions-particles.md)
- 2.3 Chemical Properties
  - [2.3.1 Ionic Compounds](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/2-3-1-ionic-compounds.md)
  - [2.3.2 Chemical Properties of Ionic Compounds](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/2-3-2-chemical-properties-of-ionic-compounds.md)
  - [2.3.3 Small Molecules](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/2-3-3-small-molecules.md)
  - [2.3.4 Chemical Properties of Small Molecules](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/2-3-4-chemical-properties-of-small-molecules.md)
  - [2.3.5 Molecular Forces - Polymers](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/2-3-5-molecular-forces-polymers.md)
  - [2.3.6 Molecular Forces - Polypropene](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/2-3-6-molecular-forces-polypropene.md)
  - [2.3.7 Giant Covalent Structures](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/2-3-7-giant-covalent-structures.md)
  - [2.3.8 Metals](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/2-3-8-metals.md)
  - [2.3.9 Alloys](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/2-3-9-alloys.md)
  - [2.3.10 Conductors](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/2-3-10-conductors.md)
  - [2.3.11 Carbon Structures - Diamond](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/2-3-11-carbon-structures-diamond.md)
  - [2.3.12 Carbon Structures - Graphite](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/2-3-12-carbon-structures-graphite.md)
  - [2.3.13 Carbon Structures - Graphene](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/2-3-13-carbon-structures-graphene.md)
  - [2.3.14 Carbon Structures - Fullerenes](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/2-3-14-carbon-structures-fullerenes.md)
  - [2.3.15 Carbon Structures - Summary](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/2-3-15-carbon-structures-summary.md)
  - [2.3.16 Clumps](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/2-3-16-clumps.md)
  - [2.3.17 Nanoparticles](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/2-3-17-nanoparticles.md)
  - [2.3.18 Nanotechnology](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/2-3-18-nanotechnology.md)
  - [2.3.19 Nanotechnology 2](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/2-3-19-nanotechnology-2.md)
  - [2.3.20 Surface Area to Volume Ratio](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/2-3-20-surface-area-to-volume-ratio.md)
  - [2.3.21 Nanotechnology Uses](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/2-3-21-nanotechnology-uses.md)
  - [2.3.22 End of Topic Test - Chemical Bonding](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/2-3-22-end-of-topic-test-chemical-bonding.md)
  - [2.3.23 Grade 9 - Bonding & Structure](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/2-3-23-grade-9-bonding-and-structure.md)
  - [2.3.24 Exam-Style Questions - Allotropes of Carbon](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/2-3-24-exam-style-questions-allotropes-of-carbon.md)
  - [2.3.25 Diagnostic Misconceptions - Conducting Electricity](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/2-3-25-diagnostic-misconceptions-conducting-electricity.md)
  - [2.3.26 Diagnostic Misconceptions - Small Molecules](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/2-3-26-diagnostic-misconceptions-small-molecules.md)
  - [2.3.27 Diagnostic Misconceptions - Drawing Polymers](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/2-3-27-diagnostic-misconceptions-drawing-polymers.md)

### 3 Quantitative Chemistry
- 3.1 Chemical Measurements
  - [3.1.1 Conservation of Mass](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/3-1-1-conservation-of-mass.md)
  - [3.1.2 Relative Formula Mass](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/3-1-2-relative-formula-mass.md)
  - [3.1.3 Calculating Relative Formula Mass](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/3-1-3-calculating-relative-formula-mass.md)
  - [3.1.4 Relative Formula Mass - Calculations](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/3-1-4-relative-formula-mass-calculations.md)
  - [3.1.5 Changing Mass](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/3-1-5-changing-mass.md)
  - [3.1.6 Measuring Mass](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/3-1-6-measuring-mass.md)
  - [3.1.7 Equations](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/3-1-7-equations.md)
  - [3.1.8 Empirical Formula](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/3-1-8-empirical-formula.md)
  - [3.1.9 Introducing Moles](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/3-1-9-introducing-moles.md)
  - [3.1.10 Relative Formula Mass](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/3-1-10-relative-formula-mass.md)
  - [3.1.11 Amounts of Substance](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/3-1-11-amounts-of-substance.md)
  - [3.1.12 Moles to Balance Equations](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/3-1-12-moles-to-balance-equations.md)
  - [3.1.13 Limiting Reactants](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/3-1-13-limiting-reactants.md)
  - [3.1.14 Concentration of Solutions](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/3-1-14-concentration-of-solutions.md)
  - [3.1.15 Moles - Calculations](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/3-1-15-moles-calculations.md)
  - [3.1.16 Percentage Yield](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/3-1-16-percentage-yield.md)
  - [3.1.17 Calculating Yield](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/3-1-17-calculating-yield.md)
  - [3.1.18 Percentage Yield - Calculations](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/3-1-18-percentage-yield-calculations.md)
  - [3.1.19 Moles & Yield](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/3-1-19-moles-and-yield.md)
  - [3.1.20 Moles & Yield 2](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/3-1-20-moles-and-yield-2.md)
  - [3.1.21 Atom Economy](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/3-1-21-atom-economy.md)
  - [3.1.22 Reaction Pathway](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/3-1-22-reaction-pathway.md)
  - [3.1.23 Atom Economy - Calculations](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/3-1-23-atom-economy-calculations.md)
  - [3.1.24 Concentrations of Solute](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/3-1-24-concentrations-of-solute.md)
  - [3.1.25 Calculating the Amount of  Solute](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/3-1-25-calculating-the-amount-of-solute.md)
  - [3.1.26 Amount of Substance in Relation to Volumes and Gas](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/3-1-26-amount-of-substance-in-relation-to-volumes-and-gas.md)
  - [3.1.27 Concentrations & Amounts - Calculations](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/3-1-27-concentrations-and-amounts-calculations.md)
  - [3.1.28 Empirical Formula - Calculations](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/3-1-28-empirical-formula-calculations.md)
  - [3.1.29 End of Topic Test - Quant Chemistry](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/3-1-29-end-of-topic-test-quant-chemistry.md)
  - [3.1.30 Grade 9 - Quantitative Chemistry](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/3-1-30-grade-9-quantitative-chemistry.md)
  - [3.1.31 Exam-Style Questions - Moles](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/3-1-31-exam-style-questions-moles.md)
  - [3.1.32 Diagnostic Misconceptions - Calculating RFM](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/3-1-32-diagnostic-misconceptions-calculating-rfm.md)
  - [3.1.33 Diagnostic Misconceptions - Moles](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/3-1-33-diagnostic-misconceptions-moles.md)

### 4 Chemical Changes
- 4.1 Acids, Alkalis & Redox Reactions
  - [4.1.1 Acids & Alkalis](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/4-1-1-acids-and-alkalis.md)
  - [4.1.2 Redox Reactions - Oxidation](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/4-1-2-redox-reactions-oxidation.md)
  - [4.1.3 Redox Reactions - Metal Oxide](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/4-1-3-redox-reactions-metal-oxide.md)
- 4.2 Reactivity of Metals
  - [4.2.1 Reactivity Diagram](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/4-2-1-reactivity-diagram.md)
  - [4.2.2 Displacement Reactions](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/4-2-2-displacement-reactions.md)
  - [4.2.3 Displacement Reactions - Halogens](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/4-2-3-displacement-reactions-halogens.md)
  - [4.2.4 Reactions with Water](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/4-2-4-reactions-with-water.md)
  - [4.2.5 Reactions with Acid](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/4-2-5-reactions-with-acid.md)
  - [4.2.6 Reactivity Tests](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/4-2-6-reactivity-tests.md)
  - [4.2.7 Reactivity Tests 2](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/4-2-7-reactivity-tests-2.md)
  - [4.2.8 Extraction of Metals](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/4-2-8-extraction-of-metals.md)
  - [4.2.9 Exam-Style Questions - Displacement Reactions](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/4-2-9-exam-style-questions-displacement-reactions.md)
- 4.3 Reactions of Acids
  - [4.3.1 Reactions of Metals with Acids](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/4-3-1-reactions-of-metals-with-acids.md)
  - [4.3.2 Redox Reactions](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/4-3-2-redox-reactions.md)
  - [4.3.3 Neutralisation of Acids](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/4-3-3-neutralisation-of-acids.md)
  - [4.3.4 Soluble Salts](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/4-3-4-soluble-salts.md)
  - [4.3.5 Required Practical: Separating Mixtures](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/4-3-5-required-practical-separating-mixtures.md)
  - [4.3.6 The pH Scale](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/4-3-6-the-ph-scale.md)
  - [4.3.7 Numerical pH Scale](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/4-3-7-numerical-ph-scale.md)
  - [4.3.8 Measuring pH](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/4-3-8-measuring-ph.md)
  - [4.3.9 Neutralisation & Titrations](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/4-3-9-neutralisation-and-titrations.md)
  - [4.3.10 Neutralisation & Titrations 2](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/4-3-10-neutralisation-and-titrations-2.md)
  - [4.3.11 Neutralisation & Titrations 3](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/4-3-11-neutralisation-and-titrations-3.md)
  - [4.3.12 Neutralisation & Titrations 4](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/4-3-12-neutralisation-and-titrations-4.md)
  - [4.3.13 Strong and Weak Acids](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/4-3-13-strong-and-weak-acids.md)
  - [4.3.14 Required Practical: Titration](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/4-3-14-required-practical-titration.md)
- 4.4 Electrolysis
  - [4.4.1 Electrolysis Process](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/4-4-1-electrolysis-process.md)
  - [4.4.2 Molten Ionic Compound](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/4-4-2-molten-ionic-compound.md)
  - [4.4.3 Metal Extraction](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/4-4-3-metal-extraction.md)
  - [4.4.4 Electrolysis of Aqueous Solutions](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/4-4-4-electrolysis-of-aqueous-solutions.md)
  - [4.4.5 Required Practical: Electrolysis](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/4-4-5-required-practical-electrolysis.md)
  - [4.4.6 Half Equations](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/4-4-6-half-equations.md)
  - [4.4.7 End of Topic Test - Chemical Changes](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/4-4-7-end-of-topic-test-chemical-changes.md)
  - [4.4.8 Grade 9 - Chemical Changes](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/4-4-8-grade-9-chemical-changes.md)
  - [4.4.9 Exam-Style Questions - Electrolysis](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/4-4-9-exam-style-questions-electrolysis.md)

### 5 Energy Changes
- 5.1 Exothermic & Endothermic Reactions
  - [5.1.1 Energy Conservation](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/5-1-1-energy-conservation.md)
  - [5.1.2 Exothermic Reactions](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/5-1-2-exothermic-reactions.md)
  - [5.1.3 Endothermic Reactions](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/5-1-3-endothermic-reactions.md)
  - [5.1.4 Required Practical: Temperature Changes](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/5-1-4-required-practical-temperature-changes.md)
  - [5.1.5 Reaction Profiles Requirements](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/5-1-5-reaction-profiles-requirements.md)
  - [5.1.6 Reaction Profiles](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/5-1-6-reaction-profiles.md)
  - [5.1.7 Reaction Profiles - Catalysed vs Uncatalysed](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/5-1-7-reaction-profiles-catalysed-vs-uncatalysed.md)
  - [5.1.8 Reaction Profiles - Chemical Bonds](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/5-1-8-reaction-profiles-chemical-bonds.md)
  - [5.1.9 Diagnostic Misconceptions - Source of Energy](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/5-1-9-diagnostic-misconceptions-source-of-energy.md)
- 5.2 Chemical Cells & Fuel Cells
  - [5.2.1 Chemical Cells](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/5-2-1-chemical-cells.md)
  - [5.2.2 Changing Voltage Output](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/5-2-2-changing-voltage-output.md)
  - [5.2.3 Batteries](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/5-2-3-batteries.md)
  - [5.2.4 Charging of Cells](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/5-2-4-charging-of-cells.md)
  - [5.2.5 Fuel Cells](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/5-2-5-fuel-cells.md)
  - [5.2.6 Hydrogen Fuel Cell](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/5-2-6-hydrogen-fuel-cell.md)
  - [5.2.7 Hydrogen as an Alternative](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/5-2-7-hydrogen-as-an-alternative.md)
  - [5.2.8 End of Topic Test - Energy Changes](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/5-2-8-end-of-topic-test-energy-changes.md)
  - [5.2.9 Grade 9 - Energy Changes](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/5-2-9-grade-9-energy-changes.md)
  - [5.2.10 Exam-Style Questions - Fuel Cells](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/5-2-10-exam-style-questions-fuel-cells.md)

### 6 The Rate & Extent of Chemical Change
- 6.1 Rate of Reaction
  - [6.1.1 Chemical Reactions](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/6-1-1-chemical-reactions.md)
  - [6.1.2 Plotting Reaction Rates](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/6-1-2-plotting-reaction-rates.md)
  - [6.1.3 Required Practical: Effect of Concentration](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/6-1-3-required-practical-effect-of-concentration.md)
  - [6.1.4 Collision Theory](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/6-1-4-collision-theory.md)
  - [6.1.5 Key Factors of Rate of Reaction](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/6-1-5-key-factors-of-rate-of-reaction.md)
  - [6.1.6 Catalysts](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/6-1-6-catalysts.md)
  - [6.1.7 Catalysts in Industry](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/6-1-7-catalysts-in-industry.md)
- 6.2 Reversible Reactions
  - [6.2.1 Reversible Reactions](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/6-2-1-reversible-reactions.md)
  - [6.2.2 Dynamic Equilibrium](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/6-2-2-dynamic-equilibrium.md)
  - [6.2.3 Conditions and Equilibrium](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/6-2-3-conditions-and-equilibrium.md)
  - [6.2.4 Equilibrium Position - Temperature](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/6-2-4-equilibrium-position-temperature.md)
  - [6.2.5 Equilibrium Position - Pressure](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/6-2-5-equilibrium-position-pressure.md)
  - [6.2.6 Equilibrium Position - Concentration](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/6-2-6-equilibrium-position-concentration.md)
  - [6.2.7 End of Topic Test - Rates of Reaction](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/6-2-7-end-of-topic-test-rates-of-reaction.md)
  - [6.2.8 Grade 9 - Rate & Extent of Chemical Change](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/6-2-8-grade-9-rate-and-extent-of-chemical-change.md)
  - [6.2.9 Exam-Style Questions - Reversible Reactions](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/6-2-9-exam-style-questions-reversible-reactions.md)
  - [6.2.10 Diagnostic Misconceptions - Temperature](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/6-2-10-diagnostic-misconceptions-temperature.md)
  - [6.2.11 Diagnostic Misconceptions - Pressure](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/6-2-11-diagnostic-misconceptions-pressure.md)
  - [6.2.12 Diagnostic Misconceptions - Concentration](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/6-2-12-diagnostic-misconceptions-concentration.md)
  - [6.2.13 Diagnostic Misconceptions - Catalysts](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/6-2-13-diagnostic-misconceptions-catalysts.md)

### 7 Organic Chemistry
- 7.1 Carbon Compounds
  - [7.1.1 Crude Oil](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/7-1-1-crude-oil.md)
  - [7.1.2 Properties of Hydrocarbons](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/7-1-2-properties-of-hydrocarbons.md)
  - [7.1.3 Alkanes](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/7-1-3-alkanes.md)
  - [7.1.4 Smallest Alkanes](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/7-1-4-smallest-alkanes.md)
  - [7.1.5 Fractional Distillation](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/7-1-5-fractional-distillation.md)
  - [7.1.6 Process of Fractional Distillation](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/7-1-6-process-of-fractional-distillation.md)
  - [7.1.7 Homologous Series](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/7-1-7-homologous-series.md)
  - [7.1.8 Burning Hydrocarbons](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/7-1-8-burning-hydrocarbons.md)
  - [7.1.9 Heavy Fractions of Crude Oil](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/7-1-9-heavy-fractions-of-crude-oil.md)
  - [7.1.10 Cracking](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/7-1-10-cracking.md)
  - [7.1.11 Uses of Alkenes](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/7-1-11-uses-of-alkenes.md)
  - [7.1.12 Exam-Style Questions - Organic Compounds](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/7-1-12-exam-style-questions-organic-compounds.md)
- 7.2 Alkenes & Alcohols
  - [7.2.1 Structure of Alkenes](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/7-2-1-structure-of-alkenes.md)
  - [7.2.2 The Shortest Alkenes](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/7-2-2-the-shortest-alkenes.md)
  - [7.2.3 Reactions of Alkenes](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/7-2-3-reactions-of-alkenes.md)
  - [7.2.4 Types of Alkene Reactions](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/7-2-4-types-of-alkene-reactions.md)
  - [7.2.5 Alcohols](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/7-2-5-alcohols.md)
  - [7.2.6 The Smallest Alcohols](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/7-2-6-the-smallest-alcohols.md)
  - [7.2.7 Reactions of Alcohols](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/7-2-7-reactions-of-alcohols.md)
  - [7.2.8 Fermentation](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/7-2-8-fermentation.md)
  - [7.2.9 Carboxylic Acids](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/7-2-9-carboxylic-acids.md)
  - [7.2.10 The Smallest Carboxylic Acids](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/7-2-10-the-smallest-carboxylic-acids.md)
  - [7.2.11 Reactions of Carboxylic Acids](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/7-2-11-reactions-of-carboxylic-acids.md)
  - [7.2.12 Addition Polymers](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/7-2-12-addition-polymers.md)
  - [7.2.13 Addition Polymers Examples](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/7-2-13-addition-polymers-examples.md)
  - [7.2.14 Condensation Polymers](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/7-2-14-condensation-polymers.md)
  - [7.2.15 Amino Acids](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/7-2-15-amino-acids.md)
  - [7.2.16 Naturally Occurring Polymers - Protein (Formation)](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/7-2-16-naturally-occurring-polymers-protein-formation.md)
  - [7.2.17 Naturally Occurring Polymers - Protein (Roles)](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/7-2-17-naturally-occurring-polymers-protein-roles.md)
  - [7.2.18 Naturally Occurring Polymers - DNA](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/7-2-18-naturally-occurring-polymers-dna.md)
  - [7.2.19 Naturally Occurring Polymers - Others](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/7-2-19-naturally-occurring-polymers-others.md)
  - [7.2.20 End of Topic Test - Alkanes & Alkenes](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/7-2-20-end-of-topic-test-alkanes-and-alkenes.md)
  - [7.2.21 End of Topic Test - Alcohols, Acids & Polymers](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/7-2-21-end-of-topic-test-alcohols-acids-and-polymers.md)
  - [7.2.22 Grade 9 - Organic Chemistry](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/7-2-22-grade-9-organic-chemistry.md)
  - [7.2.23 Exam-Style Questions - Alcohols](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/7-2-23-exam-style-questions-alcohols.md)

### 8 Chemical Analysis
- 8.1 Purity, Formulations & Chromatography
  - [8.1.1 Purity](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/8-1-1-purity.md)
  - [8.1.2 Formulations](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/8-1-2-formulations.md)
  - [8.1.3 Chromatography](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/8-1-3-chromatography.md)
  - [8.1.4 Paper Chromatography 1](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/8-1-4-paper-chromatography-1.md)
  - [8.1.5 Paper Chromatography 2](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/8-1-5-paper-chromatography-2.md)
  - [8.1.6 Required Practical  - Paper Chromatography](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/8-1-6-required-practical-paper-chromatography.md)
  - [8.1.7 Diagnostic Misconceptions - Purity](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/8-1-7-diagnostic-misconceptions-purity.md)
- 8.2 Identification of Common Gases
  - [8.2.1 Identification of Hydrogen](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/8-2-1-identification-of-hydrogen.md)
  - [8.2.2 Identification of Oxygen](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/8-2-2-identification-of-oxygen.md)
  - [8.2.3 Identification of Carbon Dioxide](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/8-2-3-identification-of-carbon-dioxide.md)
  - [8.2.4 Identification of Chlorine](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/8-2-4-identification-of-chlorine.md)
- 8.3 Identifying Ions
  - [8.3.1 Flame Tests](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/8-3-1-flame-tests.md)
  - [8.3.2 Required Practical: Flame Tests](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/8-3-2-required-practical-flame-tests.md)
  - [8.3.3 Metal Hydroxides](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/8-3-3-metal-hydroxides.md)
  - [8.3.4 Metal Hydroxides 2](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/8-3-4-metal-hydroxides-2.md)
  - [8.3.5 Carbonates](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/8-3-5-carbonates.md)
  - [8.3.6 Halides](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/8-3-6-halides.md)
  - [8.3.7 Sulfates](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/8-3-7-sulfates.md)
  - [8.3.8 Methodology for Chemical Analysis](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/8-3-8-methodology-for-chemical-analysis.md)
  - [8.3.9 Methodology for Chemical Analysis 2](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/8-3-9-methodology-for-chemical-analysis-2.md)
  - [8.3.10 Flame Emission Spectroscopy](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/8-3-10-flame-emission-spectroscopy.md)
  - [8.3.11 Flame Emission Spectroscopy Analysis](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/8-3-11-flame-emission-spectroscopy-analysis.md)
  - [8.3.12 End of Topic Test - Chemical Analysis](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/8-3-12-end-of-topic-test-chemical-analysis.md)
  - [8.3.13 Grade 9 - Chemical Analysis](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/8-3-13-grade-9-chemical-analysis.md)
  - [8.3.14 Exam-Style Questions - Identification of ions](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/8-3-14-exam-style-questions-identification-of-ions.md)

### 9 Chemistry of the Atmosphere
- 9.1 The Earth's Atmosphere
  - [9.1.1 Proportions of Gases in the Atmosphere](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/9-1-1-proportions-of-gases-in-the-atmosphere.md)
  - [9.1.2 The Earth's Early Atmosphere](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/9-1-2-the-earths-early-atmosphere.md)
  - [9.1.3 Oxygen in the Atmosphere](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/9-1-3-oxygen-in-the-atmosphere.md)
  - [9.1.4 Carbon Dioxide in the Atmosphere](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/9-1-4-carbon-dioxide-in-the-atmosphere.md)
  - [9.1.5 Greenhouse Gases](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/9-1-5-greenhouse-gases.md)
  - [9.1.6 Greenhouse Gases & Human Activities](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/9-1-6-greenhouse-gases-and-human-activities.md)
  - [9.1.7 Greenhouse Gases & Climate](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/9-1-7-greenhouse-gases-and-climate.md)
  - [9.1.8 Climate Change](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/9-1-8-climate-change.md)
  - [9.1.9 Carbon Footprints](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/9-1-9-carbon-footprints.md)
  - [9.1.10 Carbon Footprints Barriers](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/9-1-10-carbon-footprints-barriers.md)
  - [9.1.11 Common Atmospheric Pollutants](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/9-1-11-common-atmospheric-pollutants.md)
  - [9.1.12 Properties of Atmospheric Pollutants](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/9-1-12-properties-of-atmospheric-pollutants.md)
  - [9.1.13 End of Topic Test - The Earth](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/9-1-13-end-of-topic-test-the-earth.md)
  - [9.1.14 Grade 9 - Chemistry of the Atmosphere](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/9-1-14-grade-9-chemistry-of-the-atmosphere.md)
  - [9.1.15 Exam-Style Questions - Earth's Atmosphere](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/9-1-15-exam-style-questions-earths-atmosphere.md)
  - [9.1.16 Diagnostic Misconceptions - Greenhouse Effect](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/9-1-16-diagnostic-misconceptions-greenhouse-effect.md)

### 10 Using Resources
- 10.1 Using the Earth's Resources
  - [10.1.1 Potable Water](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/10-1-1-potable-water.md)
  - [10.1.2 Potable Water Sources](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/10-1-2-potable-water-sources.md)
  - [10.1.3 Potable Water in the UK](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/10-1-3-potable-water-in-the-uk.md)
  - [10.1.4 Potable Water in Saudi Arabia](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/10-1-4-potable-water-in-saudi-arabia.md)
  - [10.1.5 Required Practical: Analysing and Purifying Water](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/10-1-5-required-practical-analysing-and-purifying-water.md)
  - [10.1.6 Natural Resources](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/10-1-6-natural-resources.md)
  - [10.1.7 Uses of Natural Resources](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/10-1-7-uses-of-natural-resources.md)
  - [10.1.8 Waste Water](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/10-1-8-waste-water.md)
  - [10.1.9 Sewage Treatment](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/10-1-9-sewage-treatment.md)
  - [10.1.10 Metal Ore Extraction](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/10-1-10-metal-ore-extraction.md)
  - [10.1.11 Properties of Copper](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/10-1-11-properties-of-copper.md)
  - [10.1.12 Overexploitation of Extraction Methods](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/10-1-12-overexploitation-of-extraction-methods.md)
  - [10.1.13 Alternative Extraction Methods](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/10-1-13-alternative-extraction-methods.md)
- 10.2 Life Cycle Assessments & Recycling
  - [10.2.1 Life Cycle Assessments](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/10-2-1-life-cycle-assessments.md)
  - [10.2.2 Comparative Life Cycle Assessments](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/10-2-2-comparative-life-cycle-assessments.md)
  - [10.2.3 Difficulties with LCA](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/10-2-3-difficulties-with-lca.md)
  - [10.2.4 Reducing Resource Usage](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/10-2-4-reducing-resource-usage.md)
  - [10.2.5 Reducing Use of Glass](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/10-2-5-reducing-use-of-glass.md)
  - [10.2.6 Reducing Use of Metal](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/10-2-6-reducing-use-of-metal.md)
  - [10.2.7 Exam-Style Questions - Life Cycle Assessments](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/10-2-7-exam-style-questions-life-cycle-assessments.md)
- 10.3 Using Materials
  - [10.3.1 Corrosion](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/10-3-1-corrosion.md)
  - [10.3.2 Preventing Corrosion](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/10-3-2-preventing-corrosion.md)
  - [10.3.3 Alloys](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/10-3-3-alloys.md)
  - [10.3.4 Ceramics](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/10-3-4-ceramics.md)
  - [10.3.5 Polymers](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/10-3-5-polymers.md)
  - [10.3.6 Composites](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/10-3-6-composites.md)
- 10.4 The Haber Process & NPK Fertilisers
  - [10.4.1 Plants and Nitrogen](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/10-4-1-plants-and-nitrogen.md)
  - [10.4.2 The Haber Process](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/10-4-2-the-haber-process.md)
  - [10.4.3 The Haber Process - Equation](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/10-4-3-the-haber-process-equation.md)
  - [10.4.4 The Haber Process - Trade-Offs](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/10-4-4-the-haber-process-trade-offs.md)
  - [10.4.5 Importance of Fertilisers](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/10-4-5-importance-of-fertilisers.md)
  - [10.4.6 Formulated vs Manure Fertilisers](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/10-4-6-formulated-vs-manure-fertilisers.md)
  - [10.4.7 NPK Fertilisers - N-containing Compound](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/10-4-7-npk-fertilisers-n-containing-compound.md)
  - [10.4.8 NPK Fertilisers - P-containing Compound](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/10-4-8-npk-fertilisers-p-containing-compound.md)
  - [10.4.9 NPK Fertilisers - K-containing Compound](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/10-4-9-npk-fertilisers-k-containing-compound.md)
  - [10.4.10 Nitrogen, Phosphorus and Potassium](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/10-4-10-nitrogen-phosphorus-and-potassium.md)
  - [10.4.11 End of Topic Test - Resources](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/10-4-11-end-of-topic-test-resources.md)
  - [10.4.12 Grade 9 - Using Resources](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/10-4-12-grade-9-using-resources.md)
  - [10.4.13 Exam-Style Questions - The Haber Process](https://senecalearning.com/en-gb/revision-notes/gcse/chemistry/aqa/higher/10-4-13-exam-style-questions-the-haber-process.md)