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Chemical Reactions
A free video lesson on chemical reactions — how to spot one, the main types, whether they give out or take in heat, and the rule that mass is always conserved. Followed by real quiz questions, marked instantly. No account needed.
A chemical reaction turns one set of substances into new ones. This lesson covers reactants and products, the signs of a reaction, types like combustion and neutralisation, exothermic and endothermic changes, and the important rule that mass is always conserved. It is part of Learning Hub, a UK-curriculum learning site built by a home-educating family.
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Questions parents ask
- What are the signs of a chemical reaction?
- A colour change, a gas being given off, a temperature change, or a new solid forming. If a substance has turned into something new, a reaction has happened.
- What is conservation of mass?
- In any reaction the total mass of the products equals the total mass of the reactants, because atoms are only rearranged, never created or destroyed. Magnesium oxide weighs more than the magnesium because it gained oxygen.
- Is this suitable for KS3 and GCSE?
- Yes. Chemical reactions is a core chemistry topic for Years 9 to 11 (KS3 and GCSE), and this lesson and quiz work as a clear introduction.
- Is it really free?
- The video and these questions are free with no account. The full site is £6.99 a month for the whole family, with a 14-day free trial and no card needed to start.