Zinc + Hydrochloric Acid

Zinc + Hydrochloric Acid ➜ Hydrogen + Zinc chloride
Zn + 2HCl ➜ H₂ + ZnCl₂

molecular weights:
Zn = 65.4 g/mol
2HCl = 72.91 g/mol
H₂ = 2.01 g/mol
ZnCl₂ = 136.3 g/mol

1 mole of Zn + 2 moles of HCl ➜ 1 mole of H₂ + 1 mole of ZnCl₂
65.4 g of Zn + 72.9 g of HCl ➜ 2.01 of H₂ + 136.3 g of ZnCl₂
check 65.4 + 72.9 = 138.3 = 136.3 + 2