A 10.0 L flask at 500 K is filled with 0.30 mol of hydrogen and 0.30 mol of iodine. They react as indicated below. The equilibrium constant K_c = 45.0. What are the equilibrium concentrations of the three gases?
H₂(g) + I₂(g) $\leftrightarrows$ 2HI(g)

Question

A 10.0 L flask at 500 K is filled with 0.30 mol of hydrogen and 0.30 mol of iodine. They react as indicated below. The equilibrium constant K_c = 45.0. What are the equilibrium concentrations of the three gases?
H₂(g) + I₂(g)

\leftrightarrows

2HI(g)

Quizplus · Accepted Answer

To find the equilibrium concentrations, we set up an ICE table and use the equilibrium constant expression. Initially, [H2] = [I2] = 0.03 M. At equilibrium, let x be the change in concentration for H2 and I2, so [HI] = 2x. The equilibrium expression is Kc = [HI]^2 / ([H2][I2]). Solving for x using Kc = 45.0, we find [H2] = [I2] = 0.0069 M and [HI] = 0.046 M.

A 100 L Flask at 500 K Is Filled with 0