Le Chatelier’s Principle

Evaluation/Assessment: Objective: Today I will be able to: Apply Le Chatelier’s Principle to explaining how equilibrium systems adjust to stresses of concentration, temperature, pressure and volume Evaluation/Assessment: Informal assessment: Monitoring student interactions and questions as they complete the Le Chatelier’s Principle practice. Formal assessment: Analyzing student responses to practice and the exit ticket Common Core Connection Build Strong Content Knowledge Reason abstractly and quantitatively Make sense of problems and persevere in solving them

Lesson Sequence Evaluate: Warm – Up Explain: Le Chatelier’s Principle Notes Elaborate: Le Chatelier’s Principle Practice Evaluate: Exit Ticket

Warm - Up At equilibrium, the rate of the forward reaction ____________ the rate of the reverse reaction. Under the same conditions, at equilibrium the concentrations of both reactants and products remain _____________. Equilibrium may be approached from different starting points, but at equilibrium the ratio of products to reactants will be ______________.

Objective Today I will be able to: Apply Le Chatelier’s Principle to explaining how equilibrium systems adjust to stresses of concentration, temperature, pressure and volume

Homework Finish Le Chatelier’s Principle Practice

Agenda Warm – Up Le Chatelier’s Principle Notes Le Chatelier’s Principle Practice Exit Ticket

Equilibrium Expressions Guided Inquiry Lets look at the Inquiry together and draw some conclusions!

Le Chatelier’s Principle Notes

Le Chatelier’s Principle When an equilibrium system is subjected to a change, the system will “shift” to counteract the change Example reaction A (g) + B (g)  C (g) + X kJ

A (g) + B (g)  C (g) + X kJ Add a reactant – moves to product side to consume it Add a product – moves to reactant side to consume it Remove a reactant – moves to reactant side to produce more Remove a product – moves to product side to produce more

A (g) + B (g)  C (g) + X kJ Increase temperature – because it is an exothermic reaction, shift to the reactants side Decrease temperature – shift to the products The opposite would be true for an endothermic reaction

A (g) + B (g)  C (g) + X kJ Increase pressure – move to side with less moles of gas Decrease pressure – move to side with more moles of gas Increase volume – move to side with more moles of gas Decrease volume – move to side with less moles of gas

Le Chatelier’s Principle Practice

Exit Ticket Given the following reaction: Use Le Chatelier’s principle to determine what would happen if the following changes were made Increase the concentration of N2 Increase the concentration of NH3 Remove NH3 from the reaction after it is made