What is it
Students learn to distinguish physical and chemical changes, write simple word equations for reactions, and understand that mass is conserved during a chemical reaction because atoms are rearranged, not created or destroyed.
Why it matters
Conservation of mass is one of chemistry's most important laws, and this topic sets up balancing chemical equations, a core GCSE chemistry skill.
Exam tip
Look for clue words distinguishing chemical from physical change — 'new substance formed' and 'not easily reversed' point to chemical; 'same substance, different state' points to physical.
Related topics
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