Conservation in Chemical Reactions Quick Check

Question

3 of 53 of 5 Items
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)
Responses

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

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

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

Zn + 2HCl → H2 + ZnCl2

Answer 1

To determine which equation has the same number of atoms on both sides (reactants and products), we need to count the total number of atoms for each equation.

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.

2. CO2 + H2O → CH2OH + O2

   • Reactants: 1 C + 2 O (from CO2) + 2 H + 1 O (from H2O) = 5 atoms
   • Products: 1 C + 6 H + 3 O = 10 atoms
   • Not balanced.

3. CH4 + O2 → CO2 + 2H2O

   • Reactants: 1 C + 4 H + 2 O = 7 atoms
   • Products: 1 C + 2 O + 4 H = 7 atoms
   • Balanced.

4. Zn + 2HCl → H2 + ZnCl2

   • Reactants: 1 Zn + 2 H + 2 Cl = 5 atoms
   • Products: 1 H + 1 Zn + 2 Cl = 4 atoms
   • Not balanced.

Based on the counts, the equation CH4 + O2 → CO2 + 2H2O is the only one where the number of atoms in the reactants is the same as the number of atoms in the products.

Answer: CH4 + O2 → CO2 + 2H2O