Grade 10 · Theory
Physical and chemical change
Matter and classification · about 3 min
Visual overview: Physical and chemical change1 MIN READ
2 study sections · pause after each one and recall the key ideaA physical change alters form; a chemical change makes new substances. Telling them apart is a core skill.
Key points- Physical change: no new substance, easily reversed, mass and composition unchanged (melting, dissolving).
- Chemical change: new substances form, usually hard to reverse, energy is absorbed or released.
- Evidence of chemical change: gas produced, precipitate formed, colour change, temperature change.
- Mass is conserved in both — atoms are only rearranged.
- Precipitate — an insoluble solid formed in solution.
- Conservation of mass — total mass before equals total mass after.
EXAM TIP
dissolving salt is physical (the salt is recoverable); burning is chemical (the products are new substances).