Answer:
From a complete chemical equation, you can determine the reactants and products that were involved in the reaction. For each reactant and product, you will also know its physical state (like aqueous, liquid, solid or gas) before and after the reaction.
You can also determine the type of reaction that it was (like single/double displacement, neutralization, combustion, synthesis or decomposition).
In a balanced equation, you will also know how many atoms there were.