5/6/14 no QOTD today Today’s Learning Target: You should be able to define the term “dynamic equilibrium” and be able to give an example of what it means.
Activity Today we are going to do an activity involving the concept of chemical equilibrium. Hopefully you read the “reversible reactions and dynamic equilibrium” handout that was homework last night! It will help you with today’s activity so please take it out! Also send a group member to pick up today’s activity. We will debrief the activity in about 30 minutes. If you finish early, please ask me for the homework. HW = review WS (quiz on Friday)
Activity 1 Answers Equilibrium constant = 27/13 = 2.07 (about 2)
Activity 2 Answers Equilibrium constant = 40/20 = 2 (same as before)
Activity 3 Answers Equilibrium constant = 35/5 = 7 (higher forward transfer rate = higher equilibrium constant = more products)
Definitions • Reversible reaction A reaction that can go forward or backward. So reactants form products, but the products also decompose to remake reactants. • Dynamic equilibrium When the amounts of reactants and products do NOT change over time. The forward and reverse reactions STILL HAPPEN (but at the same rate) so overall there is no change in amount of reactants or products. • Le Chatelier’s Principle If a reaction is NOT at equilibrium, it will move toward equilibrium (but BOTH forward and reverse reactions will continue to happen)
Questions • Describe what it means when a reaction is in a state of chemical equilibrium. Both the forward and reverse reactions keep happening. But they occur at the same speed so there is no change in the amount of product or reactant. • How do the rates of forward and reverse reactions change throughout the reaction? One slows down and the other speeds up until they reach the same rate • How does a reaction with a large equilibrium constant compare to a reaction with a smaller equilibrium constant? Support your answer using the data you obtained above. With a small equilibrium constant, you end up with a smaller amount of products than you would with a higher equilibrium constant (so you keep more of the reactants than you would with a higher equilibrium constant)
Homework • review WS (due tomorrow) • Unit quiz on Friday!