Section 01
Balanced equations
Mass is conserved: atoms are neither created nor destroyed. Coefficients (numbers in front of formulas) balance the count of each element on both sides.
Section 02
Five reaction types
Synthesis (A + B → AB), decomposition (AB → A + B), single replacement (A + BC → AC + B), double replacement (AB + CD → AD + CB), and combustion (fuel + O₂ → CO₂ + H₂O).
Section 03
Signs of a reaction
A color change, a precipitate, gas bubbles, a temperature change, or light emission all suggest that a chemical change has occurred.