Final answer:
Chemical equations use symbols to represent the physical states of substances, such as solids, liquids, gases, and aqueous solutions.
Step-by-step explanation:
In chemical equations, the physical state of matter is often indicated using symbols such as (s) for solid, (l) for liquid, (g) for gas, and (aq) for aqueous (dissolved in water). For example, 2 NaHCO3(s) → Na2CO3(s)+CO2(g)+H2O(1).