Which of the following is the correctly balanced chemical equation for the reaction of sulfur dioxide with oxygen to form sulfur trioxide?

• A. 2 SO2(g) + O2(g) → 2 SO3(g)
• B. 2 SO2(g) + 3 O2(g) → 2 SO3(g)
• C. SO2(g) + 1/2 O2(g) → SO3(g)
• D. SO2(g) + O2(g) → SO3(g)

Answer: (A)

Verified step by step guidance

1. Identify the reactants and products in the chemical reaction. Here, the reactants are sulfur dioxide (SO2) and oxygen (O2), and the product is sulfur trioxide (SO3).
2. Write the unbalanced chemical equation using the chemical formulas of the reactants and products: SO2 + O2 → SO3.
3. Count the number of atoms of each element on both sides of the equation. Initially, there are 1 sulfur and 2 oxygen atoms on the reactant side, and 1 sulfur and 3 oxygen atoms on the product side.
4. Balance the equation by adjusting the coefficients to ensure the same number of each type of atom on both sides. Start by balancing the sulfur atoms, which are already balanced with 1 sulfur atom on each side.
5. Balance the oxygen atoms by adjusting the coefficients. To balance the oxygen atoms, place a coefficient of 2 in front of SO2 and SO3, and a coefficient of 1 in front of O2, resulting in the balanced equation: 2 SO2 + O2 → 2 SO3.