Initially a vessel is charged at 1000K with SO3 at a partial pressure of 0.5atm. At equilibrium the SO3 partial pressure is 0.2atm. Calculate the value of Kp at 1000K. 2SO3->2SO2+O2
My answer:
0.5-0.2=0.3atm
SO2=0.3atm*2/2mol= 0.3
O2=0.3atm*1/2mol=0.8
Therefore 0.8-0.3=0.5
Tbook answer: 0.338
You should have set up an ICE chart.
.........2SO3 ==> 2SO2 + O2
I.........0.5.....0.......0
C.........-2x.....2x......x
E......0.5-2x.....2x.......x
The problem tells you that 0.5-2x = 0.2
Solve for x and evaluate SO2 and O2, substitute into Keq and solve for K.
I get 0.3375 which rounds to 0.338.
To calculate the value of Kp at 1000K for the reaction 2SO3 -> 2SO2 + O2, you need to use the equilibrium expression for Kp. The equilibrium expression is given by:
Kp = (P(SO2)² * P(O2)) / (P(SO3)²)
Where P(SO2), P(O2), and P(SO3) represent the partial pressures of SO2, O2, and SO3, respectively.
Given that at equilibrium the SO3 partial pressure is 0.2 atm, and initially it was 0.5 atm, you can calculate the change in the SO3 partial pressure:
Change in SO3 partial pressure = 0.5 atm - 0.2 atm = 0.3 atm
Since the stoichiometry of the reaction is 2SO3 -> 2SO2 + O2, the change in partial pressure of SO2 will be equal to half the change in SO3 partial pressure:
Change in SO2 partial pressure = (0.3 atm) / 2 = 0.15 atm
Similarly, the change in partial pressure of O2 will be equal to half the change in SO3 partial pressure:
Change in O2 partial pressure = (0.3 atm) / 2 = 0.15 atm
Now, you can calculate the partial pressures of SO2 and O2 at equilibrium:
Partial pressure of SO2 at equilibrium = Initial partial pressure of SO2 - Change in SO2 partial pressure
= 0.5 atm - 0.15 atm = 0.35 atm
Partial pressure of O2 at equilibrium = Initial partial pressure of O2 - Change in O2 partial pressure
= 0.5 atm - 0.15 atm = 0.35 atm
Plugging the partial pressure values into the equilibrium expression for Kp:
Kp = (0.35 atm)² * (0.35 atm) / (0.2 atm)²
= 0.1225 * 0.35 / 0.04
= 0.042875 / 0.04
= 1.071875
Therefore, the value of Kp at 1000K is approximately 1.071875, which can be rounded to 1.072.