Reaction Quotient: Calculate

Question

Consider the following reaction where K_c = 55.6 at 698 K.

H₂(g) + I₂(g) 2HI(g)

A reaction mixture was found to contain 4.49×10^-2 moles of H₂(g), 4.26×10^-2 moles of I₂(g) and 0.289 moles of HI(g), in a 1.00 liter container.

Is the reaction at equilibrium?

If not, what direction must it run in order to reach equilibrium?

The reaction quotient, Q_c, equals ____.

The reaction___

A. must run in the forward direction to reach equilibrium.

B. must run in the reverse direction to reach equilibrium.

C. is at equilibrium.

Answer 1

H₂(g) + I₂(g) <==> 2HI(g)

Kc = 55.6

Q = [HI]² / [H₂][I₂] = (0.289)² / (4.49x10^-2)(4.26x10^-2) = 43.7 = Qc

The reaction IS NOT at equilibrium because Q does not equal Kc

The reaction A. must run in the forward direction to reach equilibrium (because Q < Kc)