To determine which of the given chemical equations has the same number of atoms in the reactants as in the products, we can count the atoms on both sides of each equation.
-
CH₄ + O₂ → CO₂ + 2H₂O
- Reactants: C (1) + H (4) + O (2) = 1 + 4 + 2 = 7 atoms
- Products: C (1) + O (2) + H (4) = 1 + 2 + 4 = 7 atoms
- Total: 7 atoms on both sides.
-
Zn + 2HCl → H₂ + ZnCl₂
- Reactants: Zn (1) + H (2) + Cl (2) = 1 + 2 + 2 = 5 atoms
- Products: H (2) + Zn (1) + Cl (2) = 2 + 1 + 2 = 5 atoms
- Total: 5 atoms on both sides.
-
Li₂CO₃ → LiO + CO₂
- Reactants: Li (2) + C (1) + O (3) = 2 + 1 + 3 = 6 atoms
- Products: Li (1) + O (1) + C (1) + O (2) = 1 + 1 + 1 + 2 = 5 atoms
- Total: 6 atoms (reactants) vs 5 atoms (products).
-
CO₂ + H₂O → CH₂OH + O₂
- Reactants: C (1) + O (2) + H (2) + O (1) = 1 + 2 + 2 + 1 = 6 atoms
- Products: C (1) + H (2) + O (1) + O (2) = 1 + 2 + 1 + 2 = 6 atoms
- Total: 6 atoms on both sides.
Upon evaluating all the equations:
- The equations CH₄ + O₂ → CO₂ + 2H₂O, Zn + 2HCl → H₂ + ZnCl₂, and CO₂ + H₂O → CH₂OH + O₂ all have the same number of atoms in the reactants and products.
The equation Li₂CO₃ → LiO + CO₂ does not balance.
Thus, the equations with equal total atoms on both sides are 1, 2, and 4:
- CH₄ + O₂ → CO₂ + 2H₂O
- Zn + 2HCl → H₂ + ZnCl₂
- CO₂ + H₂O → CH₂OH + O₂