In which chemical equation is the number of atoms in the reactants the same as the number of atoms in the products?(1 point)

Question

Responses

CH4 + O2 → CO2 + 2H2O
CH 4 + O 2 → CO 2 + 2H 2 O

Li2CO3 → LiO + CO2
Li 2 CO 3 → LiO + CO 2

Zn + 2HCl → H2 + ZnCl2
Zn + 2HCl → H 2 + ZnCl 2

CO2 + H2O → CH2OH + O2
CO 2 + H 2 O → CH 2 OH + O 2

Answer 1

To determine which chemical equation has the same number of atoms in the reactants as in the products, we can count the total number of atoms on each side of the equations:

1. CH4 + O2 → CO2 + 2H2O

   • Reactants:
     • C: 1 (from CH4)
     • H: 4 (from CH4)
     • O: 2 (from O2)
     • Total: 1 + 4 + 2 = 7 atoms
   • Products:
     • C: 1 (from CO2)
     • H: 4 (from 2H2O)
     • O: 3 (2 from CO2 + 1 from 2H2O)
     • Total: 1 + 4 + 3 = 8 atoms
   • Not balanced.

2. Li2CO3 → LiO + CO2

   • Reactants:
     • Li: 2 (from Li2CO3)
     • C: 1 (from Li2CO3)
     • O: 3 (from Li2CO3)
     • Total: 2 + 1 + 3 = 6 atoms
   • Products:
     • Li: 1 (from LiO)
     • C: 1 (from CO2)
     • O: 3 (from LiO and CO2)
     • Total: 1 + 1 + 3 = 5 atoms
   • Not balanced.

3. Zn + 2HCl → H2 + ZnCl2

   • Reactants:
     • Zn: 1 (from Zn)
     • H: 2 (from 2HCl)
     • Cl: 2 (from 2HCl)
     • Total: 1 + 2 + 2 = 5 atoms
   • Products:
     • H: 2 (from H2)
     • Zn: 1 (from ZnCl2)
     • Cl: 2 (from ZnCl2)
     • Total: 2 + 1 + 2 = 5 atoms
   • Balanced.

4. CO2 + H2O → CH2OH + O2

   • Reactants:
     • C: 1 (from CO2)
     • O: 3 (2 from CO2 and 1 from H2O)
     • H: 2 (from H2O)
     • Total: 1 + 3 + 2 = 6 atoms
   • Products:
     • C: 1 (from CH2OH)
     • H: 2 (from CH2OH)
     • O: 3 (1 from CH2OH and 2 from O2)
     • Total: 1 + 2 + 3 = 6 atoms
   • Balanced.

The only equation where the number of atoms is the same in the reactants and products is:

Zn + 2HCl → H2 + ZnCl2

So the answer is: Zn + 2HCl → H2 + ZnCl2.