Question

) In the Haber process for ammonia, K = 0.036 for the reaction N2(g) + 3H2(g) ⇔ 2NH3(g) at 50K. If a reactor is charged with partial pressures of 0.020 bar of N2 and 0.020 bar of H2, what will be the equilibrium partial pressure of (a) N2; (b) H2; and (c) NH3? Enter the answers in bar to two significant figures and do not enter the units.

Answer 1

N2(g) + 3H2(g) ⇔ 2NH3(g)

I       0.02         0.02         0

C       -x           -3x           2x

E       0.02-x   0.02-3x      2x

KP   = PNH3^2/PN2PH2^3

0.036   = (2x)^2/(0.02-x)(0.02-3x)

0.036*(0.02-x)(0.02-3x)   = 4x²

   x = 0.0016

PH2 = 0.02-3x    = 0.02-3*0.0016 = 0.0152bar

PN2   = 0.02-x   = 0.02-0.0016        = 0.0184bar

PNH3   = 2x         = 2*0.0016bar    = 0.0032bar