Question

In which chemical equation is the number of atoms in the reactants the same as the number of atoms in the products?

1:Li2CO3 → LiO + CO2
2:Zn + 2HCl → H2 + ZnCl2
3:CO2 + H2O → CH2OH + O2
4:CH4 + O2 → CO2 + 2H2O

Answer 1

To determine which chemical equation has the same number of atoms in the reactants and products, we need to balance the equations by counting the atoms of each element on both sides.

1. **Li2CO3 → LiO + CO2**
- Reactants: 2 Li, 1 C, 3 O (Total: 6 atoms)
- Products: 1 Li, 1 C, 3 O (Total: 5 atoms)
- Not balanced.

2. **Zn + 2HCl → H2 + ZnCl2**
- Reactants: 1 Zn, 2 H, 2 Cl (Total: 5 atoms)
- Products: 1 H, 1 Zn, 2 Cl (Total: 4 atoms)
- Not balanced.

3. **CO2 + H2O → CH2OH + O2**
- Reactants: 1 C, 2 O (from CO2), 2 H, 1 O (from H2O) = 1 C, 3 O, 2 H (Total: 6 atoms)
- Products: 1 C, 2 H, 1 O (from CH2OH), 2 O (from O2) = 1 C, 2 H, 3 O (Total: 6 atoms)
- Not balanced.

4. **CH4 + O2 → CO2 + 2H2O**
- Reactants: 1 C (from CH4), 4 H (from CH4), 2 O (from O2) = Total: 1 C, 4 H, 2 O (Total: 7 atoms)
- Products: 1 C (from CO2), 2 H (from 2 H2O), 2 O (from CO2) + 2 O (from 2 H2O) = 1 C, 4 H, 3 O (Total: 7 atoms)
- Not balanced.

None of the provided equations are balanced; therefore, the number of reactants does not equal the number of products.

Let me correct my assessment.
- The first equation is not balanced.
- The second equation is balanced.
- The third equation is not balanced.
- The fourth equation is balanced.

Therefore, the correct answer is that **the equation \( 2: Zn + 2HCl → H2 + ZnCl2 \) is properly balanced with 5 atoms on each side, making it the equation where the number of atoms in the reactants equals the number of atoms in the products**.

Let me know if you have additional questions!