Here's how to figure out the correct reaction:
* Standard states: Nitrogen (N₂) is a gas at standard conditions, and oxygen (O₂) is also a gas.
* Enthalpy of formation: This is a positive value (+33.1 kJ/mol), indicating that the reaction is endothermic (requires energy input).
The correct reaction is:
1/2 N₂(g) + O₂(g) → NO₂(g) ΔH = +33.1 kJ/mol
Explanation:
* 1/2 N₂(g): This represents half a mole of nitrogen gas, ensuring we produce one mole of NO₂.
* O₂(g): This represents one mole of oxygen gas.
* NO₂(g): This represents one mole of nitrogen dioxide gas, the product.
* ΔH = +33.1 kJ/mol: This indicates that the reaction requires 33.1 kJ of energy to form one mole of NO₂.
Why other options are incorrect:
* Any reaction not involving N₂ and O₂ as reactants would be incorrect.
* Any reaction with a negative ΔH would represent an exothermic process, not the formation of NO₂.
* Any reaction producing a different amount of NO₂ would not reflect the standard enthalpy of formation.
