Kc ques - confused

Confused on ques 2.c)
So i worked out thre units to be mol-1dm3 which is wrong. You have one product at the top and 2 reactants at the bottom so you gwt 1 over moldm-3 which i reversed to get mol-1dm3

For part c i got 0.036^2 divided by [SO2]^2 × 0.18 = 15
Rearranging i got sq root of 0.18 x 15 al divided by 0.036^2 which is wrong. In the answer they have the fraction reversed. Help please

I thought Kc was constant regardless of concentration of products or reactants as the position of equilibrium shifts to counteract any change in concentration? I'll give you a free bump as i'm equally as puzzled.

Kw is always constant, Kc doesnt have to be

Whats kw

Ionic product of water, basically its the equilibrium constant for 2 H2O <-> h3o+ + oh-

I thought Kc only changed with temperature. Changes in concentration doesn't affect it. At least that's what my A level ocr text book states.

looking for unknown SO2 concentration so rearrange equation to get [SO2]² = [SO3]² / Kc x [O2]

sub in known values [SO2]² = [0.36]² / 15 x [0.18]
[SO2]² = 0.048
[SO2] = 0.219 or 0.22

looking for unknown SO2 concentration so rearrange equation to get [SO2]² = [SO3]² / Kc x [O2]

sub in known values [SO2]² = [0.36]² / 15 x [0.18]
[SO2]² = 0.048
[SO2] = 0.219 or 0.22

What about the units i got 1/moldm-3 which is mol-1dm3 but in the book it says moldm-3 ???

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