What is the rate expression for the disappearance of sulfur dioxide (SO2) in the reaction 2SO2(g) + O2(g) → 2SO3(g)?

• A. Rate = k[SO2]^2[O2]
• B. Rate = k[SO3]^2
• C. Rate = k[SO2][O2]
• D. Rate = k[SO2][O2]^2

Answer: (A)

Verified step by step guidance

1. Understand that the rate expression for a reaction is determined by the rate law, which is an equation that relates the rate of a reaction to the concentration of the reactants.
2. Identify the balanced chemical equation for the reaction: 2SO2(g) + O2(g) → 2SO3(g). This indicates that sulfur dioxide (SO2) and oxygen (O2) are reactants, and sulfur trioxide (SO3) is the product.
3. Recognize that the rate expression for the disappearance of a reactant is typically based on the concentrations of the reactants involved in the rate-determining step.
4. Consider the stoichiometry of the reaction: 2 moles of SO2 react with 1 mole of O2. This suggests that the rate of disappearance of SO2 might depend on its concentration squared, due to its stoichiometric coefficient.
5. Formulate the rate expression based on the stoichiometry and typical rate law form: Rate = k[SO2]^2[O2], where k is the rate constant, [SO2] is the concentration of sulfur dioxide, and [O2] is the concentration of oxygen.