Chemical Systems and Equilibrium

1. Chemical Systems and Equilibrium - Dynamic Equilibrium -

2. Learning Goals • I will be able to explain the concept of chemical equilibrium and its relationship to the concentrations of reactants and products in a reaction

3. Success Criteria • key vocabulary: chemical equilibrium, dynamic equilibrium, equilibrium position, reversible reaction • explain factors that affect equilibria • list types of equilibrium - solubility, phase, and chemical equilibrium • identify the 5 experimental conditions that must be met for dynamic equilibria to occur

4. explain what it means if the percent yield is <1%, >99% or between 1%-99% • identify classes of chemical reactions at equilibrium • define reversible reaction • use ice tables and reaction progress graphs to determine equilibrium concentrations of reactants and products

5. Key Vocabulary • Dynamic • a force of action, movement, and change • Static • stationary, not acting or changing

6. Equilibrium You Tube Videos • http://www.youtube.com/watch?v=mmB-mIG1cEw • http://www.youtube.com/watch?v=DjEGZF_5F6s • http://www.youtube.com/watch?v=ENOKzMvvXt4

7. Factors that affect equilibria • Temperature • Pressure • Addition of product or reactant to the reaction vessel

8. Types of Equilibria

9. FIVE Experimental Conditions • The system must be closed • The reaction must be reversible • The rate of the forward reaction must be equal to the rate of the backward • The concentration of the reactants and products must be constant but not necessarily equal • The macroscopic properties must be equal

10. Percent Reaction Concentration at Equilibrium x 100 % Theoretical yield

11. If Percent Reaction is < 1% • Reaction favours the reactants very strongly • Mixing reactants has no observable result

12. If Percent Reaction is > 99% • Reaction favours the products very strongly • Reactions are observed to be complete (quantitative) “usually” written with a single arrow – reverse reaction is negligible

13. If Percent Reaction is 1% - 99% • Reaction favours reactants (closer to 1%) or products (closer to 99%) • If in a closed system, these reactions can achieve equilibrium