achieve question

[905934944]

I am confused as to how you would do this question (5.35 on achieve)

[Chem_Mod]

Hi!

Please see the solution manual for help.

First, you should identify which chemical species are increasing with time, versus which species are decreasing with time. If they are increasing with time, they are products. If they are decreasing with time, they are reactants. You can then compare the start time to the end time for each chemical species. You can see the partial pressure of A changes by 10, as well as C, but the partial pressure of B only changes by 5. Therefore, C is being produced as twice the amount of B. So, the stoichiometric coefficient in front of C is twice that in front of B, which is also the same as A. You can also look at the shape of the graphs; C is clearly twice the magnitude of B at equilibrium, and the A curve matches the C curve exactly, just reflected over an axis since one is a product and one is a reactant. You can think of this question as a graphical ICE table.
You then write the K as we have done from the balanced chemical equation.
Hope this helps!