How can I balance the equation ##Zn + HCl -> ZnCl_2 + H_2##?

##Zn +2HCl -> ZnCl_2 + H_2 ##

The method I find it useful when it comes to balancing a chemical equation is to draw a chart corresponding to the number of moles: (Split compounds into one unit of its own but, for polyatomic count them as one whole unit) Unbalanced chemical equation: Zn + HCl = ZnCl2 + H2Reactant side: Zn= 1 H=1 X 2 =2 moles of hydrogen Cl=1 X 2 = 2 moles of

Product side: Zn=1 H=2 Cl=2

The reason why you need to balance a chemical equation because energy is conserved throughout the chemical process.

Balanced chemical equation: Zn + 2HCl = ZnCl2 + H2

There are two hydrogens and two chlorines on the left and right sides.