Mixtures vs Compounds Explorer
Look at each particle set, decide whether it is an element, a compound, or a mixture, then click a zone to classify it. Particle colours and bond lines show how atoms are connected. All computation runs in your browser.
Particle Sets — click one, then drop it into a zone
Atom colour legend
Reference Guide
Elements
An element is a pure substance made of only one type of atom. It cannot be broken down into simpler substances by chemical means.
- O₂ – oxygen gas, two oxygen atoms bonded together
- N₂ – nitrogen gas, two nitrogen atoms bonded together
- Fe – iron, all iron atoms in a lattice
- Cu – copper, all copper atoms
Even though O₂ has two atoms, it is still an element because both atoms are the same type.
Compounds
A compound is a pure substance formed when two or more different elements are chemically bonded in a fixed ratio. The properties of a compound are very different from its elements.
- H₂O – water, hydrogen and oxygen chemically bonded
- NaCl – table salt, sodium and chlorine bonded
- CO₂ – carbon dioxide, carbon and oxygen bonded
You need a chemical reaction to separate the elements in a compound. Boiling water does not split it into hydrogen and oxygen.
Mixtures
A mixture is formed when two or more substances are physically combined. Each substance keeps its own chemical identity and the mixture can be separated by physical means.
- Saltwater – homogeneous, separated by evaporation
- Sand and water – heterogeneous, separated by filtration
- Air – homogeneous mixture of N₂, O₂, and other gases
Homogeneous mixtures look uniform throughout. Heterogeneous mixtures have visible different parts.
How to Tell Them Apart
Use these questions to classify a substance:
- Is every particle the same type of atom? If yes, it is an element.
- Are different atoms chemically bonded in a fixed ratio? If yes, it is a compound.
- Are two or more substances mixed but not bonded? If yes, it is a mixture.
The key difference between a compound and a mixture is the chemical bond. Compounds require a chemical reaction to separate; mixtures do not.
Separating Mixtures
Because the substances in a mixture keep their own identities, you can use physical methods to pull them apart.
- Filtration – passes a mixture through a filter paper to remove an insoluble solid (sand from water)
- Evaporation – heats a solution so the liquid evaporates and leaves the dissolved solid behind (salt from saltwater)
- Distillation – heats a mixture and collects the vapour that condenses at different temperatures (separating gases in air)
- Magnetic separation – pulls magnetic materials from a mixture using a magnet (iron filings from sand)
