Science · KS3 · Chemical Reactions
KS3 Chemical Reactions Practice for Years 7–9
A chemical reaction forms new substances. At KS3, pupils learn to describe reactions using evidence, represent them with word equations and apply conservation ideas while meeting patterns such as combustion and acid reactions.
What to understand in this topic
- distinguish a chemical reaction from a simple change of state
- identify reactants and products in a word equation
- apply conservation of mass to a closed-system model
- recognise common evidence for reaction while understanding that observations must be interpreted carefully
A common point of confusion
Bubbles do not prove that every change is chemical; boiling water also produces gas bubbles. Evidence must be considered alongside what substances are present and whether new substances are formed.
Try a quick example
Question: In the word equation magnesium + oxygen → magnesium oxide, which substances are the reactants?
Answer: Magnesium and oxygen.
Reactants are the starting substances written on the left side of the reaction arrow.
This is a fixed educational example on the page, not a customer result and not a live tutor response.
What a parent can try at home
Use word equations from school notes and cover either the reactants or products. Ask the child to identify which side contains starting substances and which contains substances formed. Do not conduct unsupervised chemical reactions at home.
How NexEdu practises this
NexEdu can practise reaction vocabulary, word equations and conservation reasoning. It does not conduct chemistry experiments or provide chemical-safety supervision; practical chemistry belongs in an appropriately supervised setting.
NexEdu provides guided questions throughout the child’s available daily tutoring time. A hint can follow an incorrect answer, and two consecutive incorrect answers trigger a brief reteach before practice continues. Same-day topic progress can resume where the child left off.
Related learning
About the information on this page
The educational summary helps parents understand the science topic and its place in the National Curriculum in England. Online practice does not replace supervised practical work, safety instruction or professional health advice where relevant.