Unit 2, Lesson 9: Equilibrium Calculations – Part I These calculations are extremely difficult. During this section of the unit, it will especially important to pay close attention to the examples given, and to do the assigned practice problems.

The Equilibrium Constant The equilibrium constant, Keq, is an experimentally determined value and cannot be derived from theory. Using experimental data and the equilibrium expression, various types of calculations can be made... 5 min

Example A A 2.0 L bulb contains 6.00 mol of NO2(g), 3.0 mol of NO(g) and 0.20 mol of O2(g) at equilibrium. What is Keq for 2 NO(g) + O2(g) 2 NO2(g)? *Note: you can ignore the units of Keq since they are somewhat complicated and have little significance for you at this point in time. Write expression, find concentrations, then sub in values. – 5 min

Brain Break! Brain break! – 5 min

Example B 4.00 mol of NO2(g) is introduced into a 2.00 L bulb. After a while, equilibrium is attained according to the equation 2 NO(g) + O2(g) 2 NO2(g). At equilibrium, 0.500 mol of NO(g) is found. What is the Keq value? *Note: We cannot treat this question in the same way as the previous one, because now there is a factor of time to be considered. ICE table, fill in known values, find changes based on stoichiometry. – 10 min

Practice Time! Pg. 70 #47-49 25 min