Week 2 Sapling #9

[Tanya Bearson 2K]

In this question, why do we use K = [NO]^2/[N2][O2] instead of its reciprocal with NO as a reactant? I'm confused because I thought that since we are adding NO which makes the reaction shift left we would need to use the K for the reverse reaction.

[Adalia 3E]

I don't think we need to use the reverse reaction to calculate concentrations when adding the product, you only need to use ICE to account for the change in concentrations of both sides of the equations.

[HannahRobinson3L]

Hello, just to add on, in this case, just because the reaction favors the left, we don't need to use the reverse reaction's K. We simply are increasing the concentration of product, which will result in a greater concentration of the reactant.

[Pranav Daggubati 3C]

The direction you do it in results in reciprocal values of Kc. This is because Kc would be flipped if reversed. However, the question asks for the Kc related to the forward reaction.

[kateraelDis1L]

Hi, this one confused me also. I guess even after the addition you don't have to use the reverse reaction, all you have to do it account for the change in your ice table and solve for x like normal. Iv'e been looking for more practice like this one.