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
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•
•
•
•
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/h
owtosolveit/
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 10th 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 15th 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-