5.35 finding partial pressure

[Sarah Blake-2I]

In question 5.35, you are given a graph for A, B, and C. You are asked to write an equation and calculate the k value. I am just confused as to how I would find the exact partial pressure values for the K equation just by looking at the graph. I am unsure how to add the graph onto this post but the question I am referring is on pg. 438 and any explanation or help would be appreciated! Thank you!

[JasonLiu_2J]

The y-axis on the graph gives the partial pressures in terms of kPa. Since 1pKA is equal to 0.01 bar, you can convert the equilibrium partial pressures in the graph from pKa to bars and use those partial pressures for the equilibrium constant equation.

[Renee Grange 1I]

We are given the partial pressure in pKa on the y axis. We can use the fact that 1 pKa = .01 bar when setting up the equilibrium constant.
Kp = (Pb)(Pc)^2/ (Pa)^2
Kp = (5/100)(10/100)^2/(18/100)^2
This gives up the equilibrium constant for the reaction.