A sample of gaseous SO 3 was introduced into anevacuated flask so that the press
ID: 679231 • Letter: A
Question
A sample of gaseous SO3 was introduced into anevacuated flask so that the pressure of pure SO3 wouldbe 0.5800 atm at 522 K.But, SO3 decomposes to gaseous SO2 andO2.
At equilibrium the TOTAL pressure in the flask wasmeasured at 0.7308 atm. CalculateKp at this temperature for thereaction SO3(g) SO2(g) + 1/2 O2(g) Base your calculationson the reaction as written above A sample of gaseous SO3 was introduced into anevacuated flask so that the pressure of pure SO3 wouldbe 0.5800 atm at 522 K.
But, SO3 decomposes to gaseous SO2 andO2.
At equilibrium the TOTAL pressure in the flask wasmeasured at 0.7308 atm. CalculateKp at this temperature for thereaction Base your calculationson the reaction as written above
Explanation / Answer
Using the balanced equation, you are going to lose x atm ofpressure for SO3, SO2 is going to gain x atm, and O2 will gain .5 xatm. The equilibrium pressure will therefore be: SO3 = .5800 - x SO2 = x O2 = .5x The total pressure will be equal to the sum of the partialpressures of all products and reactants. Therefore: .7308 atm = .58 -x + x +.5x x = .3016 atm Plugging the x value back into the equations from above, theequilbrium pressures are: SO3 = .5800 - .3016 = .2784 atm SO2 = .3016 atm O2 = (.5)(.3016) = .1508 atm Using the coefficients from the balanced equation: Kp = Pso2 P1/2o2 /Pso3 = (.3016)(.1508)1/2/ .2784 = .4207