Final answer:
To calculate the equilibrium concentration of oxygen gas when NO and NO2 concentrations are equal at equilibrium and K is 5.0 x 10^-5, we use the expression for the equilibrium constant. Since [NO]=[NO2], the concentration of O2 at equilibrium can be found as [O2] = 1/K, resulting in [O2] = 2.0 x 10^4 M.
Step-by-step explanation:
The student has asked to calculate the equilibrium concentration of oxygen gas (O₂) when the concentration of nitrogen monoxide (NO) and nitrogen dioxide (NO₂) are equal at equilibrium for the reaction 2 NO(g) + O₂(g) ⇌ 2 NO₂(g), given that the equilibrium constant K is 5.0 x 10-5. To calculate the equilibrium concentration of O₂, we can use the equilibrium constant expression:
K = [NO₂]2 / ([NO]2 * [O₂])
Since [NO] and [NO₂] are equal at equilibrium, we can substitute [NO] for [NO₂] in the equation, which simplifies to:
K = 1 / [O₂]
By rearranging for [O₂], we get:
[O₂] = 1 / K
Substitute K = 5.0 x 10-5:
[O₂] = 1 / (5.0 x 10-5)
[O₂] = 2.0 x 104 M
This calculation assumes that the reaction system is at equilibrium and that the concentrations of reactants and products don't change significantly from the start of the reaction to the point of equilibrium.