Answer to Question #347456 in General Chemistry for Ashter

Question

Sulfur trioxide decomposes at high temperature in a sealed container according to the reaction 2SO₃(g) ⇆ 2SO₂(g) + O₂(g)

Initially, the vessel is charged at 1000 K with SO₃(g) at a partial pressure of 0.500 atm. At equilibrium the SO₃ partial pressure is 0.200 atm. At equilibrium the SO₃ partial pressure is 0.200 atm. Calculate the value of Kp at 1000 K.

Strategy:

Using the equilibrium table, tabulate the given intial and equilibrium partial pressures. Denote the changes in partial pressure using a variable as guided by stoichiometric coefficients in the balanced chemical equation. Solve for the unknown to calculate for the equilibrium partial pressures of SO₂ and O₂ and then solve for Kp.

Answer 1

0,5-0,2=0,3 reacted

2SO₃ = 2SO₂ + O₂

2 SO₃ —> 2 SO₂ — 1 O₂

0,3 SO₃ —> X — Y

X= 0,3*2/2= 0,3 SO₂

Y= 0,3*1/2= 0,15 O₂

$K_p = \frac{[SO_2]²[O_2]} {[SO_3]²}$

$K_p = \frac{[0,3]²[0,15]} {[0,2]²}= 0,3375$

Answer: K_p = 0,3375