To determine which chemical equation has the same number of atoms in the reactants as in the products, let's analyze each equation provided:
-
Li₂CO₃ → LiO + CO₂
- Reactants:
- 2 Li
- 1 C
- 3 O
- Products:
- 1 Li
- 1 O
- 1 C
- 2 O (from CO₂)
- Total:
- Reactants: 2 + 1 + 3 = 6 atoms
- Products: 1 + 1 + 1 + 2 = 5 atoms
- Reactants:
-
Zn + 2HCl → H₂ + ZnCl₂
- Reactants:
- 1 Zn
- 2 H
- 2 Cl
- Products:
- 2 H
- 1 Zn
- 2 Cl
- Total:
- Reactants: 1 + 2 + 2 = 5 atoms
- Products: 2 + 1 + 2 = 5 atoms
- Reactants:
-
HOCO₂ + 2H₂O
- This appears to be incomplete and lacks a product. I'll assume it is meant to be a balanced equation. We need products to compare.
-
C₂H₅OH + O₂
- This is also incomplete without products. Assuming it is intended to indicate combustion which typically produces CO₂ and H₂O.
To summarize:
Analyzing the second equation, Zn + 2HCl → H₂ + ZnCl₂, both sides balance perfectly with 5 atoms in total (3 in the reactants: 1 Zn, 2 H, and 2 Cl; and 5 in the products: 2 H and 1 Zn and 2 Cl).
Therefore, the equation where the number of atoms in the reactants equals the number of atoms in the products is:
Zn + 2HCl → H₂ + ZnCl₂.