Question

The reaction below was observed in a 4.0 L flask at 100oC.

N2O4 (g) ↔ 2 NO2(g)

Initially, 0.2 mol of N2O4 and 0.2 mol of NO2 were placed in the flask. If the kp = 11 atm , will the reaction proceed toward products or reactants?

Toward reactants

Toward products

It's at equilibrium

Answer 1

I tried towards reactants and that was wrong... Maybe it's equilibrium?

Answer 2

@Photon336

Answer 3

You can calculate molar concentrations of each of them and then find \(\sf Q_c\). Compare it with \(\sf K_c\). If \(\sf Q_c>K_c\) then reaction will be backwards or forward otherwise. You can find \(\sf K_c\) by using the equation

\(\sf K_p = K_c \times (RT)^{\Delta n}\)

Answer 4

agree with abhisar, you can figure out Qc which is relatively easy


\[Qc = \frac{ [NO_{2}]^{2} }{ [N_{2}O_{4}] } = [0.05M]^{2}/[0.05] = 1 \]

However as abhisar said you would need to convert Kp and compare it to Kc then this would tell you what direction the reaction is going.

Answer 5

Qc=1
Kc=0.359
1>0.359 so backwards.
Wouldn't that mean more reactants are formed? :/ @Abhisar @Photon336

Answer 6

So technically we know that Qc = 1
so 0.359 is the value of Kc right?

Right away because Qc and Kc are not equal you know that the reaction has not reached equilibrium or should I say at equilibrium.

so if Q>K that means that there are too many products, so the equilibrium will shift to form more reactants until the Q = K and equilibrium is established.

Answer 7

Thank you! @Photon336

Answer 8

No problem