[Isomer]

In a class of 30, 10 of us think B is correct. The rest think C. What do you think?

At 900 K, the equilibrium constant for reaction this reaction

2 SO2 + O2 <----> 2 SO3 is 13.0.

The equilibrium concentrations are [SO2] = 0.361 mol/L
                                                [SO3] = 0.840 mol/L

Given the above values, the calculated equilibrium concentration of O2 is

B. 0.416 mol/L

C. 2.40 mol/L

Here is the equation I used.. 13 = (0.840) squared divided by unknown x (0.361) squared.

I hope you guys can understand that. Are the 10 of us right?

[Dan]

13 = (0.840) squared divided by unknown x (0.361) squared.

Yeah,

K = [SO₃]² / [SO₂]²[O₂]

[sdekivit]

yeah, B is correct

[Isomer]

My teacher still says C is correct! So we took it to another chem teacher who agreed with us!

[sdekivit]

tell your teacher that in general for a homogenous sytem mA + nB <--> qC + rD the equilibruim fraction will be

Q_c = ( [C]^q[D]^r ) / ( [A]^mn ) = K_c

and let him read a good chemistry book. (omg what a n00b)

[stoneburner]

Easy enough error to make - the question is, is the equilibrium constant products over reactants, or reactant over products? The teacher just confused, and got it backward, is all. (But should have recognized the error as soon as you questioned him about it).