Question 11.75 (Sixth Edition)

[Steve Magana 2I]

Question: Consider the equilibrium 3 NH3(g) + 5 O2(g) <---> 4 NO(g) + 6 H2O(g). (a) What happens to the partial pressure of NH3 when the partial pressure of NO is increased? (b) Does the partial pressure of O2 decrease when the partial pressure of NH3 is decreased?

Can someone help me with this please, I'm a bit stuck. Thank you!

[Rachana Jayaraman 1H]

For a), the partial pressure of NH3 should increase. Since P = [conc]RT an increase in partial pressure signifies an increase in the concentration of NO, so the reaction will shift towards the reactants. As a result, more NH3 will be produced and the partial pressure of NH3 will increase. Another way to think about it is by considering the K expression K = (PNH3)^3(PO2)^5/(PNO)^4(PH2O)^6. Since K is constant, if the partial pressure of a reactant increases, the partial pressure of the products have to increase in order to keep the value of K the same.

For b), the partial pressure of NO should increase. If the partial pressure of NH3 decreases, the equilibrium will shift towards the reactants so more O2 is produced. This in turn increases the partial pressure of O2.

[404982241]

Firstly, that chemical equation is incorrect. I think the book messed up. But for part a) NO will increase
b)no, o2 will increase. think of it like a sew saw