Question

Ammonia gas combines with oxygen gas to produce liquid water and nitrogen gas. a) Write a balanced equation for the equilibrium reaction b) Write the expression for the equilibrium constant c)Calculate Keq if the equilibrium concentrations of the following components are: [NH3]=0.3M; [O2]=0.5M; [H2O]=55.6M; [N2]=2.0M d) Experiments show that this reaction is endothermic, what effect will raising the temperature have on the position of equilibrium? Explain. Explain why a reaction reaches equilibrium and why we refer to it as a dynamic equilibrium.

Answer 1

a)

The raction

2NH3 + 3/2O2 = 3H2O + N2

b)

the K eq

Ke = [H2O]^3[N2]/[NH3]^2[O2]^(3/2)

since activity of water = 1

Keq =  [N2]/[NH3]^2[O2]^(3/2)

c)

calculate if

Keq =  [2]/[0.3]^2[0.5]^(3/2)

Keq = 62.83

d)

if you increase T, then you will favour production of water and gas, since they require T to b eproduced, the shift goes to right

dyunamic equilibrium = the overall change is zero, but there is still movement of moleucles (i.e rate in = 2 and rate out = 2, the overal 2-2 = 0)