Which of the following chemical equations correctly demonstrates the conservation of atoms?

• A. 2H_2 + O_2 ightarrow 2H_2O
• B. C + O_2 ightarrow CO
• C. N_2 + 2H_2 ightarrow NH_3
• D. Na + Cl_2 ightarrow NaCl

Answer: (A)

Verified step by step guidance

1. Identify the number of atoms of each element on both sides of each chemical equation to check if atoms are conserved.
2. For the equation \$2H_2 + O_2 \rightarrow 2H_2O$, count atoms on the reactant side: 4 hydrogen atoms and 2 oxygen atoms; on the product side: 4 hydrogen atoms and 2 oxygen atoms. This shows conservation of atoms.
3. For the equation \(C + O_2 \rightarrow CO\), count atoms on the reactant side: 1 carbon atom and 2 oxygen atoms; on the product side: 1 carbon atom and 1 oxygen atom. Oxygen atoms are not balanced, so atoms are not conserved.
4. For the equation \(N_2 + 2H_2 \rightarrow NH_3\), count atoms on the reactant side: 2 nitrogen atoms and 4 hydrogen atoms; on the product side: 1 nitrogen atom and 3 hydrogen atoms. Both nitrogen and hydrogen atoms are not balanced, so atoms are not conserved.
5. For the equation \(Na + Cl_2 \rightarrow NaCl\), count atoms on the reactant side: 1 sodium atom and 2 chlorine atoms; on the product side: 1 sodium atom and 1 chlorine atom. Chlorine atoms are not balanced, so atoms are not conserved.