Question

Zn + HCl → ZnCl2 + H2 balance the equation

Answer 1

Start with one element, and work your way to the last element. There are 3 elements in this one, H, Cl, and Zn.

Answer 2

Easiest to start with is hydrogen. There is one H on the left side, in HCl. But there are 2 hydrogen on the right side, because of the dihydrogen.
So, you'd have to get 2 H on the left. What you'd do is now have 2 moles of HCl.
So, HCl becomes 2 HCl.

Answer 3

please you have to apply the conservation of mass principle, so number of atoms of all chemical species has to be equal in both sides of your chemical reaction

Answer 4

ZN + 2 HCl = ZNCl2 + H2