Kc and Kp Conversions Hesss Law in Equilibrium

Kc and Kp Conversions Hess’s Law in Equilibrium Constants

• Today I will be able to: – Convert between Kp and Kc – Apply Hess’s Law to calculating equilibrium constants • Informal assessment – monitoring student interactions as they complete the practice problems • Formal assessment – analyzing responses to the practice prblems

Lesson Sequence • • • Evaluate: Warm Up Explain: Notes Explore: Webquest Elaborate: Practice Problems Evaluate: Closure

Warm Up

Objectives • Today I will be able to: – Convert between Kp and Kc – Apply Hess’s Law to calculating equilibrium constants

Homework • Continue working practice problems and reading chapter 5

Agenda • • • Warm Up Notes Webquest Practice Problems Closure

Equilibrium Constants and Hess’s Law Notes

Manipulating Equilibrium Constants The equilibrium constant of a reaction in the reverse reaction is the reciprocal of the equilibrium constant of the forward reaction.

Manipulating Equilibrium Constants The equilibrium constant of a reaction that has been multiplied by a number is the equilibrium constant raised to a power that is equal to that number.

Manipulating Equilibrium Constants The equilibrium constant for a net reaction made up of two or more steps can be found from the equilibrium constants for the individual steps. ` At 1565 K we have these equilibrium constants:

Example Problem 1

Answer Problem 1

Example Problem 2

Answer Problem 2

Relationship between Kp and Kc Visit the website below to find notes and examples http: //www. chem. purdue. edu/gchelp/ howtosolveit/

Relationship between Kc and Kp Substituting P=[A]RT into the expression for Kp for each substance, the relationship between Kc and Kp becomes Kp = Kc (RT) n Where: n = (moles of gaseous product) – (moles of gaseous reactant) Hint: ‘products–reactants’ and ‘products over reactants’ is a common theme in chemistry.

Practice Problems

Closure – Practice Problems • Using the 10 th edition of the textbook • Equilibrium; the Equilibrium Constant 14, 15, 19, 21, 22, 24 • Calculating Equilibrium Constants 30, 31 -33 • Applications of Equilibrium Constants 37 -38, 41 -44, 49 28 -

Closure – Practice Problems • Using the 15 th edition of the textbook • Equilibrium; the Equilibrium Constant 15, 17, 21, 23, 25, 27, 28 • Calculating Equilibrium Constants 33, 35 -37 • Applications of Equilibrium Constants 45, 41 -44, 47, 49, 51 3143 -