Which of the following chemical equations correctly models the law of conservation of mass?

• A. N_2 + 3H_2 ightarrow 2NH_3 + H_2
• B. C + O_2 ightarrow CO
• C. 2H_2 + O_2 ightarrow 2H_2O
• D. Na + Cl_2 ightarrow NaCl_2

Answer: (C)

Verified step by step guidance

1. Step 1: Understand the law of conservation of mass, which states that matter cannot be created or destroyed in a chemical reaction. This means the number of atoms of each element must be the same on both sides of the equation.
2. Step 2: For each given chemical equation, count the number of atoms of each element on the reactant side and compare it to the number on the product side.
3. Step 3: Check the first equation: \(N_2 + 3H_2 \rightarrow 2NH_3 + H_2\). Count nitrogen and hydrogen atoms on both sides to see if they balance.
4. Step 4: Check the second equation: \(C + O_2 \rightarrow CO\). Count carbon and oxygen atoms on both sides to verify if the equation is balanced.
5. Step 5: Check the third equation: \$2H_2 + O_2 \rightarrow 2H_2O$. Count hydrogen and oxygen atoms on both sides to confirm if the equation obeys the conservation of mass.