This topic explores the relationship between health and disease, covering the causes of communicable and non-communicable diseases and how they are spread. It also examines the body's natural defence mechanisms, the development and use of medicines, and the impact of lifestyle factors on human health.
This topic covers the language of chemistry: how we represent elements, compounds, and reactions using symbols and formulae. You'll learn to write and balance chemical equations, calculate relative formula masses, and use the mole concept to find amounts of substances. Mastering this is essential because it underpins all quantitative chemistry, from predicting reaction yields to understanding concentrations in solutions.
In WJEC GCSE Combined Science, this topic builds on your knowledge of atoms and bonding. You'll apply your skills to real-world contexts like calculating the mass of a product from a given reactant mass, or determining the volume of gas produced in a reaction. These calculations are fundamental for further study in chemistry and appear in many exam questions.
Why does it matter? Chemical equations are the shorthand of chemistry — they tell you exactly what happens in a reaction. The mole concept allows you to scale up from atoms to grams, making it possible to work with measurable amounts in the lab. Without these tools, chemistry would be a collection of observations with no way to predict outcomes.
Key skills and knowledge for this topic
Key points examiners look for in your answers
Expert advice for maximising your marks
Pitfalls to avoid in your exam answers
Common questions students ask about this topic
Comprehensive revision notes & examples
How questions on this topic are typically asked
Practice questions tailored to this topic