Chemical Reactions Key terms CIE Checkpoint

Chemical reaction

A process where substances change into new substances because bonds are rearranged.

Solution

A mixture where a substance is fully dissolved in a liquid.

Solute

The substance that is dissolved in a solution.

Reactant

A substance that starts a chemical reaction.

Product

A substance made during a chemical reaction.

Conservation of Mass and Energy

The idea that matter and energy are not created or destroyed in a reaction.

Displacement reaction

A reaction where a more reactive element replaces a less reactive element in a compound.

Physical change

A change in appearance, not in the substance itself (e.g. melting).

Residue

The solid left behind after filtering a mixture.

Filtrate

The liquid that passes through a filter.

Filtration

A method to separate solids from liquids using a filter.

Evaporation

A method to separate a dissolved solid from a liquid by heating.

Reactivity series

A list of metals ranked by how reactive they are.

Word equation

A way to show a chemical reaction using words (e.g. hydrogen + oxygen → water).

Symbol equation

A way to show a chemical reaction using chemical symbols (e.g. H₂ + O₂ → H₂O).

Carbonate

A compound containing carbon and oxygen, often found in rocks.

Surface area

The amount of exposed area of a substance that can react.

Concentration

How much solute is dissolved in a solution.

Reaction rate

How fast a chemical reaction happens.

Collision theory / particle theory

The idea that reactions happen when particles collide with enough energy.