The oxidation of sulfur dioxide by oxygen to sulfur trioxide has been implicated as an important step in the formation of acid rain:

2 SO_{2}(g) + O_{2}(g) ⇌ 2 SO_{3}(g)

If the equilibrium partial pressures of SO_{2}, O_{2} and SO_{3} are 0.564 atm, 0.102 atm and 0.333 atm, respectively at 1000 K, what is K_{p} at this temperature?

A. 0.292

B. 3.42

C. 5.79

D. 8.11

E. 6.05

We’re being asked to **determine the equilibrium constant (K _{p})** at 1000 K for

2 SO_{2}(g) + O_{2}(g) ⇌ 2 SO_{3}(g)

Recall that the ** equilibrium constant** is the ratio of the products and reactants.

We use **K _{p}** when dealing with pressure and

$\overline{){{\mathbf{K}}}_{{\mathbf{p}}}{\mathbf{=}}\frac{{\mathbf{P}}_{\mathbf{products}}}{{\mathbf{P}}_{\mathbf{reactants}}}}$ $\overline{){{\mathbf{K}}}_{{\mathbf{c}}}{\mathbf{=}}\frac{\mathbf{\left[}\mathbf{products}\mathbf{\right]}}{\mathbf{\left[}\mathbf{reactants}\mathbf{\right]}}}$

*Note that solid and liquid compounds are ignored in the equilibrium expression.*

Equilibrium Expressions

Equilibrium Expressions

Equilibrium Expressions

Equilibrium Expressions