Final answer:
Molecular equations express compounds as if they are undissociated molecules, while total ionic equations accurately show dissolved ionic compounds as free ions, and net ionic equations eliminate spectator ions to highlight the actual chemical change.
Step-by-step explanation:
Understanding the differences between molecular equations, total ionic equations, and net ionic equations is crucial for studying reactions, especially those occurring in aqueous solutions. In a molecular equation, reactants and products are expressed as though they are molecules, while ionic compounds that are dissolved in solution are not shown as ions. This representation does not provide a clear picture of how substances exist in solution.
In contrast, a total ionic equation provides a more accurate representation by showing all strong electrolytes as they actually exist in solution, which is as separated ions. This type of equation can reveal different states of ionic species. Step-by-step, one would first write the molecular equation, ensuring all formulas are balanced, and then write the ionic equation with all aqueous substances as ions.
The net ionic equation is derived by removing spectator ions from the total ionic equation. Spectator ions are ions that do not participate in the reaction; they appear unchanged on both sides of the chemical equation. The net ionic equation thus demonstrates how many different combinations of reactants can lead to the same chemical transformation.