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

O Li,CO3 → LiO + CO2
O CH4+02 → C02 + 2H20
0 002 + H20 → CH20H + 02
• Zn + 2HCl → H2 + ZnCl

Answer 1

To check if the number of atoms in the reactants is the same as in the products, we will analyze each equation:

1. Li2CO3 → LiO + CO2

   • Reactants: 2 Li, 1 C, 3 O (total = 6 atoms)
   • Products: 1 Li, 1 O, 1 C, 2 O (total = 5 atoms)
   • Not balanced.

2. CH4 + O2 → CO2 + 2H2O

   • Reactants: 1 C, 4 H, 2 O (total = 7 atoms)
   • Products: 1 C, 2 O, 4 H (total = 7 atoms)
   • Balanced.

3. 2O2 + H2O → CH3OH + O2

   • Reactants: 4 O, 2 H (total = 6 atoms)
   • Products: 1 C, 3 H, 5 O (total = 9 atoms)
   • Not balanced.

4. Zn + 2HCl → H2 + ZnCl2

   • Reactants: 1 Zn, 2 H, 2 Cl (total = 5 atoms)
   • Products: 1 Zn, 2 H, 2 Cl (total = 5 atoms)
   • Balanced.

From the analysis above, the equations that have the same number of atoms in the reactants and products are:

• CH4 + O2 → CO2 + 2H2O
• Zn + 2HCl → H2 + ZnCl2

Thus, the correct answer is the second equation (CH4 + O2 → CO2 + 2H2O).

Answer 2

Which statement is true regarding a chemical reaction? (1 point)
The total number of atoms does not change, so mass is conserved in the reaction.
Even if the total number of atoms changes, mass may not be conserved in the reaction.
Even if the total number of atoms does not change, mass may not be conserved in the reaction.
• The total number of atoms changes, so mass is conserved in the reaction.

Answer 3

The true statement regarding a chemical reaction is:

The total number of atoms does not change, so mass is conserved in the reaction.

This statement reflects the law of conservation of mass, which states that in a closed system, the total mass of reactants must equal the total mass of products. Since atoms are neither created nor destroyed in a chemical reaction, the total number of atoms remains the same, thus conserving mass.