Use state symbols to distinguish pure liquids from aqueous solutions in equations.

State symbols are essential in chemical equations to indicate the physical state of substances involved in a reaction. For pure liquids, the state symbol (l) is used, while for aqueous solutions, where a substance is dissolved in water, the state symbol (aq) is applied. This distinction helps clarify the conditions under which reactions occur, as the properties and behaviors of pure liquids differ from those of substances in solution. Understanding these symbols is crucial for accurately interpreting and writing chemical equations.