Question

You start with a flask at 900 K containing only sulfur trioxide at an unknown pressure and allow the equilibrium below to be established. If the final sulfur trioxide pressure is 5.00 atm, what was its initial pressure?

2 SO₂ (g) + O₂ (g)   <-->   2 SO₃ (g)     K_p = 0.345

NOTE: It is possible to choose your variables so that you get a cubic equation that is easily solvable. However, if you wind up with a more complicated cubic equation, you can solve it using numberous web calculators, such as http://www.1728.org/cubic.htm

Answer 1