What to Revise for GCSE Chemistry Paper 2

What to Revise for GCSE Chemistry Paper 2

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 2. (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. 

This article is an overview, for a more detailed list, refer to the exam board specification.

GCSE Chemistry Paper 2 (AQA Combined Scienced/Trilogy)

C8 Rates of Reaction

In this topic you will learn different techniques to measure the rate of reaction such as:

• Using a gas syringe
• Using an upturned measuring cylinder and water trough
• Using a balance to measure the decreasing mass
• The disappearing cross method

You need to know how to calculate the mean rate of reaction and also the rate of reaction at a certain point in time by calculating the gradient from a graph.

You should be able to use collision theory to explain how the following factors affect the rate of a reaction:

Temperature

Surface area

Concentration

Catalyst

You need to be able to explain what a reversible reaction is and what it means when the reaction reaches equilibrium. If you are studying for the higher tier you should be able to use Le Chatelier’s principle to predict and explain what would happen to the equilibrium if one of the conditions changes, for example, if the temperature is increased.

For revision videos on this topic click here.

C9 Organic Chemistry

This topic is all about molecules that contain carbon. You need to know how fossil fuels such as coal and oil are formed. You will then discover how fractional distillation can be used to get useful products from oil. You need to know what a hydrocarbon is and how the chemical properties of hydrocarbons changes as the length of the molecule increases. These properties include boiling point, viscosity, flammability and how cleanly they burn.

You need to know the difference between an alkane and an alkene and how bromine water can be used to distinguish an alkene from an alkane. Make sure you can draw the displayed formula for alkanes and alkenes as well as being able to write their molecular formulas and general formulas. You need to know why chemical companies carry out cracking on long chain hydrocarbons and how that process is performed. This is also a good time to revisit polymerisation from paper 1.

For revision videos on this topic click here.

C10 Chemical Analysis

In this short topic you need to know the difference between a pure substance and a mixture. You should be able to explain how the boiling point of a substance can be used to determine if it is a pure substance or a mixture. Also make sure you can describe how adding impurities to a substance changes its boiling point and melting point. It is important you can recall the definition of a formulation and give some examples of a formulation.

Make a point of learning how to test for the gases oxygen, carbon dioxide, hydrogen, and chlorine. For each one you need to describe the test and the result you would get.

Chromatography is the required practical for this topic. You need to describe how to carry out the practical including how to calculate Rf values. Also make sure you know how to analyse a chromatogram.

For revision videos on this topic click here.

C11 Chemistry of the Atmosphere

You are expected to know the percentage of gases in the atmosphere today as well as how that has changed from the early atmosphere when the Earth was formed 4500 million years ago. You need to know the main causes for the increase in oxygen levels and the decrease in the percentage of carbon dioxide.

You need to be able to state the main greenhouse gases in the Earth today and describe what human activities are causing their levels to increase. You should be able to explain how these gases contribute to the greenhouse effect and how this causes climate change. Make sure you know the consequences of climate change. It is important that you know what a carbon footprint is and how we can reduce this.

In this topic you are expected to learn about common air pollutants such as carbon dioxide, water vapour, carbon monoxide, soot, sulfur dioxide and nitrogen dioxides. You need to know how they are produced/released and the problems they cause in the environment. You also need to know all about complete and incomplete combustion.

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C12 Using Resources

In this topic you are expected to know how different sources of water such as fresh water and sea water can be treated to turn it into potable water. You need to know the difference between pure water and potable water and the test you can do in the lab to determine which is which. The required practical for this topic investigates the purity of different water samples and evaluates a method of treating the water. You are also expected  to describe how waste water from our homes (sewage), agriculture and industry is cleaned up before it can be released back into the environment.

As copper rich ores are becoming more scare, new ways have been devised to extract copper, and other metals from low grade ores. Ensure you know about phytomining and bioleaching. Both of these processes produce a solution of the metal. The metal itself is then obtained from the solution by electrolysis or displacement using scrap iron.

You must know how a life cycle assessment (LCA) can be used to assess the impact of a product. Make sure you can describe the stages of an LCA such as raw materials, manufacturing, packaging and distribution, use, and finally, disposal. You are expected to have some knowledge of how we can reduce, reuse and recycle products in order to lead a more sustainable lifestyle.

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.