IB Chemistry on Le Chatelier's Principle, Equilibrium Constant and Dynamic Equilibrium
Chem 2 - Chemical Equilibrium IV: The Properties of the Equilibrium Constant K plus Examples
-
Upload
lumen-learning -
Category
Science
-
view
150 -
download
2
Transcript of Chem 2 - Chemical Equilibrium IV: The Properties of the Equilibrium Constant K plus Examples
Chemical Equilibrium (Pt. 4)
The Properties of the Equilibrium Constant K
plus ExamplesBy Shawn P. Shields, Ph.D.
This work is licensed by Dr. Shawn P. Shields under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
Recall: The Law of Mass Action
Consider the generalized reaction
Reactants A and B
Products C and D
coefficients
Recall: The Law of Mass Action
For the reaction
The relationship between the value of the equilibrium constant K and the concentrations of reactants and products is
𝐩𝐫𝐨𝐝𝐮𝐜𝐭𝐬𝐫𝐞𝐚𝐜𝐭𝐚𝐧𝐭𝐬
Property 1: Reversing the Reaction and the Value of K
For the reaction
Reverse the reaction:
or or K-1
Property 1: Reversing the Reaction and the Value of K
If we reverse a reaction, the new K for the reversed reaction is the inverse of the original value.
or K-1
Property 2: Adding Two Reactions and the Equilibrium Constant
If we add two or more reactions together to get a new reaction, multiply the equilibrium constants together.
Reaction 1: Reaction 2:
K1K2
Property 2: Adding Two Reactions and the Equilibrium Constant
If we add two or more reactions together to get a new reaction, multiply the equilibrium constants together.Reaction 1: Reaction 2:
The new equilibrium constant K3 = K1 K2
K1K2K3
Property 3: Multiplying Coefficients by a Factor and the Equilibrium Constant
If we multiply the coefficients in a reaction by a factor, the new equilibrium constant K is the original value raised to the power equal to that factor.
Original rxn:
Mult by factor of 4: K
K4
Property 3: Multiplying Coefficients by a Factor and the Equilibrium Constant
We do the same thing if the factor is a fraction… the new equilibrium constant K is still the original value raised to the power equal to that factor.
Original rxn:
Divide coeff by 4:
K
Example 1: Reversing the Reaction and the Value of K
For the reaction below at a certain temperature,
What is the value for K for the reaction below?
Example 1 Solution
Original Reaction:
What is the value for K for the reaction or K-1
Example 2: Adding Two Reactions and the Equilibrium Constant
Add the two reactions below to get a new reaction. Determine the value for the equilibrium constant for the new reaction.Reaction 1: Reaction 2:
K1= 5.1K2 = 0.15
Example 2 Solution
Add the two reactions below to get a new reaction. Determine the value for the equilibrium constant for the new reaction.Reaction 1: Reaction 2: 2
K1= 5.11K2 = 0.150
K3 = K1 K2 = 5.11 0.150 = 0.767
Example 3: Multiplying Coefficients by a Factor and the Equilibrium Constant
For the reaction below at a certain temperature,
What is the value for K for the reaction below?
Example 3: Multiplying Coefficients by a Factor and the Equilibrium Constant
The coefficients were multiplied by
Next up, ICE Tables and Equilibrium
Calculations (Pt 5)