1. What is equilibrium? What is equal at equilibrium? What is stable at equilibrium? What must be met for a system to be at equilibrium? Draw a rate vs. time graph for a reversible rxn

2. ICE and K eq When do you use it? Suppose 3.20 moles of O 2 and 2.10 moles of N 2 were placed in a 2.00L container. At equilibrium, it was found that 1.90 moles of NO 2 were present. a. Write the equilibrium expression for this system. b. Calculate the initial concentrations of O 2 and N 2 and the equilibrium concentration of NO 2. c. Calculate the equilibrium concentrations of O2 and N2. d. Calculate the value of the equilibrium constant, K. e. Are the reactants or products favored at equilibrium?

3. K sp, solubility, and Q (will a ppt form?) The K sp of lead (II) bromide, PbBr 2, is 6.60 x 10 -6 a. Write the equilibrium equation. b. Write the solubility product expression. c. Calculate the solubility in mol/L. d. Calculate the solubility in g/L.

4. Solubility The solubility of lithium phosphate, Li 3 PO 4, is 1.4 x 10 -8 g/L. a. Calculate the solubility in mol/L. b. Write the equilibrium equation. c. Write the solubility product expression. d. Calculate Ksp.

5. Q The K sp for calcium sulfate, CaSO 4, is 4.93 X 10 -5. Will a precipitate form if the [Ca +2 ] =.0075M and the [SO4 -2 ] =.0025M? http://phet.colorado.edu/en/simulation/reve rsible-reactionshttp://phet.colorado.edu/en/simulation/reve rsible-reactions –Equilibrium simulation

6. Le Chatelier http://www.mhhe.com/physsci/chemistry/essent ialchemistry/flash/lechv17.swfhttp://www.mhhe.com/physsci/chemistry/essent ialchemistry/flash/lechv17.swf –Le Chatelier simulation Le Chatelier’s Principle –A system at equilibrium that is disturbed will react to PARTIALLY COUNTERACT the disturbance. 3 H 2 (g) + N 2 (g) 2 NH 3 (g) + energy –Increase volume –Decrease temperature –Add NH 3