What to Revise for GCSE Chemistry Paper 1 

If you are studying for the AQA Combined Science exams, sometimes called Trilogy, here is a break down of what you need to revise for Chemistry Paper 1. (Some revision guides give the topics different numbers but the content is the same)

Remember if you are studying for Separate Science there will be extra topics and also some extra content in the topics I describe below.

GCSE Chemistry Paper 1 (AQA Combined Scienced/Trilogy)

C1 Atomic Structure and Separating Techniques

Make sure you know the following:

The charges and masses of the subatomic particles- protons, neutrons and electrons. How to draw electronic structures. How the atoms of isotopes are different from each other. You need to be able to draw dot and cross diagrams to show how atoms change into ions during a chemical reaction. You’re expected to know the different ideas about atoms or models of the atom that were developed by the ancient Greeks, John Dalton, J.J. Thomson, Ernest Rutherford, Neils Bohr and James Chadwick. Make sure you can describe Thomson’s plum pudding model. You also need to describe Rutherford’s gold foil experiment and explain what ideas it gave him about atoms.

Many students forget this topic also includes separation techniques such as filtration, evaporation, distillation (simple distillation and fractional distillation) as well as chromatography. 

This key topic also includes writing word equations and writing and balancing symbol equations. Very important skills in chemistry!

For revision videos on this topic click here.

C2 The Periodic Table

In this topic you will understand how the periodic table was developed from early ideas to classify chemical elements by different scientists such as Dalton, Newlands, Dobereiner and Dmitri Mendeleev. You should be able to explain how chemical elements are arranged in the modern day periodic table.

Make sure you know where the metals and non-metals are located on the periodic table and how their properties are different.

For this topic you need to revise how group 1 metals, the alkali metals, react with water, oxygen and chlorine. You should be able to describe the trend in chemical and physical properties as you do down group 1 of the periodic table. You also need to know how to explain the reactivity trend of the alkali metals by referring to their electronic structures.

You need to remember the chemical and physical properties of group 7, the halogens. How can their displacement reactions be explained in terms of the reactivity trend of halogens. Why do halogens get more reactive going up the group? (This is the opposite of alkali metals). This can be explained by referring to their electronic structures. Halogens form diatomic molecules. What does this mean?

Make sure you know the physical and chemical properties of the noble gases (group 0). Can you explain why they are inert (unreactive) by referring to their electronic structures?

For revision videos on this topic, click here.

C3 Structure and Bonding

In this very important topic, you need to make sure you can describe and explain:

• How metals and non-metals combine together by transferring electrons during ionic bonding.
• The structure and properties of giant ionic structures
• How non-metal atoms join together through sharing electrons in covalent bonding.
• The structure and properties of simple molecules such as water.
• The structure and properties of giant covalent structures such as diamond, graphite, graphene, and silicon dioxide.
• The structure and properties of fullerenes such as Buckminster Fullerene. You also need to know the structure and properties of nanotubes.
• How metal atoms are held together by metallic bonding.
• The structure and properties of metals. For example, what makes them good conductors of heat and electricity.
• What is an alloy and how is it different from a pure metal.
• Also make sure you can describe the process of polymerisation where many small monomer molecules are joined together to make very long polymer molecules. Be sure to know the properties of polymers.

For revision videos on this topic click here.

C4 Quantitative Chemistry (Calculations)

Higher and foundation tier students need to know how to calculate the following:

• Formula mass, also called, the relative molecular mass.
• Percentage by mass of an element in a compound.
• Conservation of mass calculations.
• The concentration of a solution in g/dm3.

If you are studying for the higher tier exam, you also need to know how to calculate:

• The number of moles of a substance.
• The concentration of a solution in moles/dm3.
• The mass of product made when you’re only given the mass of one of the reactants. (These are the long moles calculations)
• The mass of reactant needed when you are given the mass of product that you want to make. (These are the long moles calculations)
• Using the mass of reactants and products to write a balanced symbol equation.

For revision videos on this topic click here.

C5 Chemical Changes

This is a large topic packed full of content that you need to learn. The first half of the topic is about the reactivity of metals and how that is used to extract them from their ores. Make sure you are familiar with:

• The reactivity series of metals
• Displacement reactions of metals
• Extraction of metals from their ores by reducing them with carbon
• Reduction and oxidation in terms of oxygen
• Reduction and oxidation in terms of electrons.
• How to write ionic equations (higher tier only)

The second half of the topic is concerned with making salts from acids. Make sure you know how to make salts from:

• Acid and metal
• Acid and base
• Acid and alkali
• Acid and carbonate

Make sure you are also familiar with:

• The pH scale
• The difference between a strong and weak acid and alkali
• What the pH number means in terms of Hydrogen ion concentration (higher tier only)

The required practical for this topic is Making a Salt.

For revision videos about this topic click here.

C6 Electrolysis

You need to know how a compound can be split apart using electricity. Make sure you know the main features of an electrolysis cell such as the anode, cathode and electrolyte.

You should be able to explain what happens to the ions during the electrolysis of molten compounds and be able to predict what substance would be discharged (made) at each electrode. You should also be able to describe how electrolysis can be used to extract aluminium from its ore (aluminium oxide). If you are studying for the higher tier you should also be able to write half equations for each electrode.

You should be able to explain what happens during the electrolysis of solutions and be able to predict what substance would be discharged (made) at each electrode after taking account of the hydrogen ions and hydroxide ions that will also be present. You should also be able to describe how electrolysis can be used to produce Hydrogen, oxygen and sodium hydroxide from sea water (brine). If you are studying for the higher tier you should also be able to write half equations for each electrode.

The required practical for this topic involves the electrolysis of solutions.

For revision videos on this topic click here. 

C7 Energy

This is a short topic but you still need to know all of the following:

The difference between an endothermic and exothermic reaction.

Examples of endothermic and exothermic reactions.

Uses of exothermic and endothermic reactions.

How to draw a reaction profile for an exothermic and endothermic reaction.

Bond energy calculations.

The required practical involves measuring the temperature change of a chemical reaction.

For revision videos on this topic click here.

Disclaimer: This is just a brief overview of each topic to give you a flavour of what you need to learn. For the nitty gritty of each topic, consult a reputable revision guide or the AQA exam specification.