When silver nitrate (AgNO₃) reacts with hydrochloric acid (HCl), a chemical change occurs. The reaction produces silver chloride (AgCl), which is a white precipitate, and nitric acid (HNO₃).
The chemical equation for the reaction is:
\[ \text{AgNO}_3 (aq) + \text{HCl} (aq) \rightarrow \text{AgCl} (s) + \text{HNO}_3 (aq) \]
In this reaction, the formation of a new substance (silver chloride) and the change in the composition of the reactants indicate that a chemical change has taken place. Physical changes involve changes in the state or appearance of a substance without altering its chemical composition, while chemical changes result in the formation of new substances.