Question

How do you write an equation for the reaction between zinc metal and hydrochloric acid (aqueous) producing zinc chloride (aqueous) and hydrogen gas?

Answer 1

A chemical reaction is the reaction in which the bonds are broken within reactant molecules and new bonds are formed within product molecules which further form new substances. During these reactions heat is evolved.

Complete answer:
Chemical equation is a mathematical statement which symbolizes the product formation from reactants whereas reactants are those substances which are starting components i.e. present on the left hand side of an arrow and product are final substances that present on the right hand side of the arrow. Reactions are done under some certain conditions or in the presence of any catalyst which is different for different reactions.
To write an equation between zinc metal and hydrochloric acid we find first we have to write the symbolic representation of zinc and hydrochloric acid which are reactants of this reaction and then also write the symbolic representation of products which are zinc chloride and hydrogen gas. So the equation can be write as:
$Zn+HCl\to ZnC{{l}_{2}}+{{H}_{2}}$
Another step is to balance the equation i.e. atoms or molecules on the reactant side and product side remain the same. Now we can see that there are 2 hydrogen atoms and chlorine atoms on the product side but on the reactant it is only one. Hence we have balance this reaction and the balanced reaction can be shown as follows:
$Zn+2HCl\to ZnC{{l}_{2}}+{{H}_{2}}$

Note: Chemical reactions are of many types like combustion reaction, de combustion reaction, neutralization reaction, redox reaction and double displacement reaction. The main property of chemical reaction is it follows the law of conservation of mass.