Science · Chemistry foundations
Properties and Changes of Matter
Estimated time includes reading and one quiz. Take the time you need.
Start here: key ideas
- An element contains one kind of atom.
- A compound has elements chemically joined in a fixed ratio.
- Mixtures can be separated by physical methods.
- A physical change keeps the substance’s identity.
- A chemical change forms new substances.
- Heating usually increases particle motion.
What you’ll be able to do
- Classify elements, compounds, and mixtures.
- Tell physical properties and changes from chemical ones.
- Explain solid, liquid, and gas behavior with particles.
Classify matter, tell physical changes from chemical changes, and connect phases to particle motion.
Optional review
If you’d like to review the basics, visit Atoms, Elements, Ions, and the Periodic Table. You can start this lesson without completing those first.
Pure substances and mixtures
A pure substance has a fixed composition. An element contains one kind of atom. A compound contains two or more elements chemically joined in a fixed ratio.
A mixture has substances physically combined in a variable ratio. A homogeneous mixture looks uniform, like salt water. A heterogeneous mixture has visibly different parts, like oil and water.
A compound cannot be separated into its elements by filtering or boiling because its atoms are chemically joined. A mixture can often be separated by physical properties. Filtration separates by particle size; distillation separates by boiling point.
You've used your 1 free study guide
Your free topic allowance is shared across Reading, Math, Science and English. This first section is a preview. Unlock every study-guide
topic — full lessons, inline checks, the complete practice bank +
timed exam simulation — with a free trial.
Your one free topic stays free, always.
$0 today — card required to start your trial. Cancel anytime before day 3.
Already subscribed? Log in.