Lecture 41/28/05

Quiz 2 1. Given the following reaction: 2 H 2 S (g) ↔ 2 H 2 (g) + S 2 (g) Calculate K c and K p at 1400 K if at equilibrium a flask contains 1 M H 2 S, 0.06 M H 2, and 0.06 M S 2.

For the reaction: CO (g) + H 2 O (g) ↔ CO 2 (g) + H 2 (g) If a reaction vessel at 673 K is charged with an equimolar mixture of CO and steam such that P CO =P H2O =2.00 atm. What are the partial pressures at equilibrium? K p = 10 at 673 K

For the reaction: CO (g) + H 2 O (g) ↔ CO 2 (g) + H 2 (g) If a reaction vessel at 673 K is charged with an equimolar mixture of CO and steam such that P CO =P H2O =2.00 atm and H 2 is added so that P H2 =0.15 atm. What are the partial pressures at equilibrium? K p = 10 at 673 K

Le Chatelier’s Principle If a system is at equilibrium and is disturbed, it will shift the equilibrium to counteract the disturbance. Ways to disturb equilibrium: Add or remove product or reactant Change the pressure or volume Change the temperature Consider Q vs. K

Add or Remove Product or reactant Add a substance and system will shift to reduce it Remove substance and system will try and replenish it

Haber Process N 2 (g) + 3 H 2 (g) ⇄ 2 NH 3 (g)

Volume or pressure change Reducing volume  shifts system to lower number of moles (affects partial pressure) Increasing volume  shifts system to increase number of moles (affects partial pressure) If you increase total pressure without increasing partial pressures (by adding an inert gas), then it does