CHEMISTRY COMMUNITY

For 8.99, why do we have to calculate the limiting reagent? The problem is as follows:
Hydrochloric acid oxidizes zinc metal in a reaction that produces hydrogen gas and chloride ions. A piece of zinc metal of mass 8.5 g is dropped into an apparatus containing 800.0 mL of 0.500 m HCl(aq). If the initial temperature
of the hydrochloric acid solution is 25 C, what is the final temperature of this solution? Assume that the density and molar heat capacity of the hydrochloric acid solution are the same as those of water and that all the heat is used to raise the temperature of the solution.

because we need the amount of mol of product, which would depend on the limiting reagent of the reaction

By finding the limiting regent you can calculate the energy released by the reaction and therefore find temperature