[NO]2 [NO2]2 [NO2]2 K1K2 = x = = K3 [N2] [O2] [NO]2 [O2] [N2] [O2] 2 N2 + O2 2NO K1 = 2.0 x 10-25 2NO + O2 2NO2 K2 = 6.4 x 109 N2 + 2O2 2NO2 K3 = ???? [NO]2 [NO2]2 [NO2]2 K1K2 = x = = K3 [N2] [O2] [NO]2 [O2] [N2] [O2] 2 2.0 x 10-25 x 6.4 x 109 = 1.28 x 10-15

2NO + O2 2NO2 Kc = 6.4 x 109 2NO2 2NO + O2 Kc = ? “K prime” 1 K’c = = 1.6 x 10-10 Kc

2NO + O2 2NO2 Kc = 6.4 x 109 4NO + 2O2 4NO2 Kc = ? “K double prime” 2 K’’c = = 4.1 x 1019 Kc

2NO + O2 2NO2 Kc = 6.4 x 109 NO + ½ O2 NO2 Kc = ? “K triple prime” K’’’c = = 8.0 x 104 Kc

[O2] [CO] [CO2] [O3] K = [CO2] [x] [O2] [x] = 16 K = [O3] [9] [CO] O3 + CO CO2 + O2 Rxn has K=16 Starts with 9 O3 & 12 CO [O2] [CO] [CO2] [O3] K = [CO2] [x] [O2] [x] = 16 K = [O3] [9] [CO] [12] Values NOT at equilibrium!!

Initially NO PRODUCTS… O3 + CO CO2 + O2 Reactants 9 12 + - Initially NO PRODUCTS… Rxn MUST move FORWARD Products 9-x 12-x +x +x (x) (x) = 16 (9-x) (12-x)

[x] [x] = 16 [9-x] [12-x] 0 = 15x2 - 336x + 1728 x = 8 or 14.4

If amount is not stated… assumed ZERO in most cases [NOCl]o = 1.0 M Kc = 1.6 x 10-5 If amount is not stated… assumed ZERO in most cases 2 NOCl 2NO + Cl2 Initial 1.0 M -2x +2x +x Change 1.0 – 2x 2x x Equilibrium [NO]2 [Cl2] (2x)2 (x) = = 1.6 x 10-5 K = [NOCl]2 (1.0 –2x)2

with small K values, you can cross x’s that are “+” or “-” = 1.6 x 10-5 [ ]o is 100 times larger… with small K values, you can cross x’s that are “+” or “-” (4x)3 1.0 = 1.6 x 10-5 x = 0.016 @ equilibrium [NO] = [Cl2] = [NOCl] = 2x = 2(0.016) = 0.032 M x = 0.016 M 1.0 – 2x = 1.0 – 2(0.016) = 0.97M

[NOCl]o = 2.0 M [Cl2]o = 1.0 M Kc = 1.6 x 10-5 2 NOCl 2NO + Cl2 2.0 M 1.0 M -2x +2x +x 2.0 – 2x 2x 1.0 + x [NO]2 [Cl2] (2x)2 (1.0 + x) = = K = 1.6 x 10-5 [NOCl]2 (2.0 –2x)2

(2x)2 (1.0 + x) = 1.6 x 10-5 (2.0 –2x)2 (1.0) (2x)2 (2.0)2 = @ equilibrium [NO] = [Cl2] = [NOCl] = 2x = 2(0.0040) = 0.0.0080 M 1.0 + x = 1.0 + 0.0040 ≈ 1.0 M 2.0 – 2x = 2.0 – 2(0.0040) = 1.992 M

REMOVES “STRESS” from the RXN can predict how certain changes in a reaction will affect the position of equilibrium REMOVES “STRESS” from the RXN Rxn will SHIFT AWAY from the ADDITION and SHIFT TOWARDS the SUBTRACTION

CuCl2(H2O)2 + 2H2O Cu(H2O)42+ + 2Cl- Rxn will SHIFT AWAY from the ADDITION and SHIFT TOWARDS the SUBTRACTION CuCl2(H2O)2 + 2H2O Cu(H2O)42+ + 2Cl-

system will shift away from the added component or towards a removed component Ex: N2 + 3H2  2NH3 if more N2 is added, then equilibrium position shifts to right if some NH3 is removed, then equilibrium position shifts to right

adding inert or uninvolved gas adding or removing gaseous reactant or product is same as changing conc. adding inert or uninvolved gas increase the total pressure doesn’t effect the equilibrium position

changing the volume decrease V decrease in # gas molecules shifts towards the side of the reaction with less gas molecules increase V increase in # of gas molecules shifts towards the side of the reaction with more gas molecules

all other changes alter the concentration at equilibrium position but don’t actually change value of K value of K does change with temperature

reactant: for endothermic reactions product: for exothermic reactions if energy is added, the reaction will shift in direction that consumes energy treat energy as a reactant: for endothermic reactions product: for exothermic reactions

N2(g) + 3H2(g) ↔ 2NH3(g) + Energy add NH3 to left add H2 to right remove N2 increase temp to left decrease volume to right add Ne gas no shift Increase P Must produce LESS gas

P4(s) + 6Cl2(g) ↔ 4PCl3(l) decrease volume to right increase volume to left add P4 remove Cl2 to left add Kr gas no shift add PCl3

energy + N2(g) + O2(g) ↔ 2NO(g) endo or exo? ∆H=181 kJ endothermic increase temp to right increase volume no shift decrease temp to left

N2(g) + 3H2(g)  2NH3(g)

2 NOCl 2NO + Cl2 9 12 -x -x +x +x 9-x 12-x x x

Video Quiz Did the lecturer have Glasses or a Mustache? There was a clipart object during a problem… House Explosion Plant Bonus Element Symbol of element that he pronounces really oddly….