Chemical Equation
A symbolic representation of a chemical reaction showing reactants on the left and products on the right.
Formula / equation
aA + bB → cC + dD
Unit
Dimensionless
In depth
State symbols in brackets — (s), (l), (g) and (aq) — record the physical form of each species, while conditions such as heat, catalyst or pressure are written above or below the arrow. A double harpoon replaces the single arrow when the reaction is reversible.
Examples in the real world
CaCO₃(s) → CaO(s) + CO₂(g) written with Δ above the arrow to show that heating is required.