Which of the following chemical equations best represents the law of conservation of mass?

• A. 2H_2 + O_2 \rightarrow H_2O
• B. H_2 + O_2 \rightarrow H_2O
• C. 2H_2 + O_2 \rightarrow 2H_2O
• D. H_2 + 2O_2 \rightarrow 2H_2O

Answer: (C)

Verified step by step guidance

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. Look at each chemical equation and count the number of atoms of each element on the reactant side and the product side.
3. For example, in the equation \$2H_2 + O_2 \rightarrow 2H_2O\(, count hydrogen atoms: on the left, \)2 \times 2 = 4\( hydrogens; on the right, \)2 \times 2 = 4\( hydrogens. For oxygen atoms: on the left, \)2\( oxygens; on the right, \)2 \times 1 = 2$ oxygens.
4. Compare this balanced equation to the others, which do not have equal numbers of atoms on both sides, indicating they do not obey the conservation of mass.
5. Conclude that the equation where the number of atoms for each element is equal on both sides best represents the law of conservation of mass.