1. WARM UP
2.00 moles of NOCl was placed in a 2.00 liter reaction vessel at 400°C. After equilibrium was established, it was found that 24% of the NOCl had dissociated according to the following equation: 2NOCl(g) NO(g) + Cl2(g). Calculate the equilibrium constant, K, for the reaction.

2. Predicting Equilibrium

3. Calculating Concentrations
Use K and initial concentrations to determine the concentrations at equilibrium
N2O NO2
K =
2.5 moles N2O4
1 L container

4. Calculating Concentrations
Set up an ICE table
Make x the change
N2O NO2
Initial
Change - x x
Equilibrium – x x

5. Calculating Concentrations
2. Write the equilibrium constant expression and solve for x
= [2x]2
[2.5 – x]

6. Calculating Concentrations
May need to create quadratic equation
ax2 + bx + c
Use formula to solve for x
-4x x
x = .053

7. Calculating Concentrations
3. Plug x into concentration values at equilibrium for all molecules
x = .053
N2O4 ( ) = 2.447
NO2 = 2(.053) = .106

8. WRAP UP
Calculate the concentration of OH- ions present after 2.7 M of the weak base, QOH (the reactant), is allowed to dissociate into its Q+ and OH- product ions. The Kb value for this process is 8.3 x 10-2.