Question

In which chemical equation is the number of atoms in the reactants the same as
the number of atoms in the products? (1 point)
Li2CO3 → LiO + CO2
CO2 + H2O → CH2OH + O2
CH4 + O2 → CO2 + 2H2O
Zn + 2HCl → H + ZnCl 2 2

Answer 1

To determine which chemical equation has the same number of atoms in the reactants as in the products, we need to count the total number of atoms for each equation provided.

1. **Li2CO3 → LiO + CO2**
- Reactants: 2 Li + 1 C + 3 O = 6 atoms
- Products: 1 Li + 1 O + 1 C + 2 O = 4 atoms
- **Not balanced (6 ≠ 4)**

2. **CO2 + H2O → CH2OH + O2**
- Reactants: 1 C + 2 O (from CO2) + 2 H + 1 O (from H2O) = 5 atoms
- Products: 1 C + 2 H + 1 O + 2 O = 6 atoms
- **Not balanced (5 ≠ 6)**

3. **CH4 + O2 → CO2 + 2H2O**
- Reactants: 1 C + 4 H + 2 O = 7 atoms
- Products: 1 C + 2 O + 4 H = 7 atoms
- **Balanced (7 = 7)**

4. **Zn + 2HCl → H2 + ZnCl2**
- Reactants: 1 Zn + 2 H + 2 Cl = 5 atoms
- Products: 1 Zn + 2 H + 2 Cl = 5 atoms
- **Balanced (5 = 5)**

From the analysis, both the third equation (CH4 + O2 → CO2 + 2H2O) and the fourth equation (Zn + 2HCl → H2 + ZnCl2) have the same number of atoms in the reactants and products.

However, since the question typically asks for a single answer, if we choose the first equation that shows balance clearly:

**Answer: CH4 + O2 → CO2 + 2H2O (3rd option)**