Sample Problems:

1. A mixture of 0.500 mol H₂ and 0.500 mol I₂ was placed in a 1.00-L stainless-steel flask at 430 ^oC. The equilibrium constant K_c for the reaction

H_{2 (g)} + I_{2 (g)} ←→2 HI _(g)

is 54.3 at this temperature. Calculate the concentrations of H₂,I₂ and HI

at equilibrium.

2. For the reaction H_{2 (g)} + I_{2 (g)} ←→2 HI _(g) at 430 ^oC, suppose that the

Initial concentrations of H₂,I₂ and HI are 0.00623 M, 0.00414 M and 0.0224 M, respectively. Calculate the concentrations of these species at equilibrium.

3. Consider the reaction H_{2 (g)} + I_{2 (g)} ←→ 2HI _(g) . Starting with the reaction of 0.040 M for HI, calculate the concentrations of H₂,I₂ and HI.

4. At 1280 ^oC the equilibrium constant (Kc) for the reaction Br_{2 (g)} ←→2 Br _(g)

is 1.1 x 10 ^-3. If the initial concentrations are [Br₂] = 6.3 x 10 ^-2 M and [Br] = 1.2 x 10 ^-2 M. Calculate the concentrations of these species at equilibrium.

5. In the reation: cis-stilbene←→trans-stilbene. The equilibrium constant for this system is 24 at 200 ^oC. Suppose that initially only cis-stilbene is present at a concentration of 0.850 mol/L. Calculate the concentrations of these species at equilibrium.

Labels: Chemistry Lecture, Sample Problems