equilibrium homework help

Question

At equilibrium, a reaction vessel contains 4.50 atm of Br₂ and 1.10 atm of NBr₃. According to the reaction: 2 NBr₃ (g) ⇌ N₂ (g) + 3 Br₂ (g) Kp = 4.8 Determine the equilibrium partial pressure of N₂.

Answer 1

Let x be Partial Pressure change in N₂ as system goes to equilibrium (partial pressure can be used as a surrogate for moles if T and V_T constant.

At equilibrium K_P = P_N2P_Br2³/P_NBr3² = 4.8

Using an ICE chart you can determine the equilibrium partial pressures in terms of x and initial conditions:

P_N2 = x

P_Br2 = 4.5 + 3x

P_NBr3 = 1.10 - 2x

Insert these into the K expression and solve for x. (numerically, as you get a quartic equation - I get .0482 atm for x. If you make the assumption that x is small, which is not typical for this K, but you have a large amount of product initially, you get x(4.5)³/1.1² = 4.8, you get .063 - not acceptable)

Please consider a tutor. Take care.