chemical equation?

Question

What is the balanced chemical equation for the reaction that occurs when HCl is added to Zn metal? And what is the chem equation when a lighted match comes in contact with the same reaction?

Answer 1

HCl and Zn go through a single replacement reaction, an oxidation-reduction reaction where the Zn will replace the H:

2H+ +2 Cl- +Zn(s) --> Zn2+ +2Cl- +H2(g)

Zn2+ and 2Cl- could be written as ZnCl2, but it's easier to see the movement of electrons how I wrote it. The 2 H's go from +1 to neutral

2H+ +2e- --> H2(g)

To balance it, the Zn goes from neutral to Zn2+ cation:

Zn(s) --> Zn2+ +2e-

Chlorine is a spectator, it stays -1 charge the whole time

Answer 2

To answer the second half of your ?,

2H2 (From reaction above) + O2 (in air) ----> 2H2O + heat