Just check this out. Manipulative
this is a manipulative you can use to change the temperature/ volume/ concentration of a reaction at equilibrium. It automatically calculates for you what the changes in the amounts of products and reactants are.
Slide the bars around and have fun.
What do you see when you change each individual bar?
Pay attention to which side of the equation the numbers change.
What can you tell about which side of the equation changes based on which bar you choose to change?
Friday, March 13, 2009
Lesson #1 Le Chatlier's Principle and its applications in Dynamic Equillibrium
Welcome Students, this week's blog is designed to help you through the concepts we will cover in class for the next two weeks. Dynamic Equilibrium is a phenomenon that occurs when the rate of formation of products is equivalent to the rate of formation of reactants. In other words, the relative amounts of each compound do not change over time.
Le Chatlier's principle explains what occurs when this dynamic equilibrium is disrupted. For the purpose of our class we will discuss three different stresses that will alter this dynamic equilibrium. These are pressure changes, temperature changes, and changes in concentration.
To begin here is a gadget that may be useful as an addition to this introduction.
Le Chatlier's principle explains what occurs when this dynamic equilibrium is disrupted. For the purpose of our class we will discuss three different stresses that will alter this dynamic equilibrium. These are pressure changes, temperature changes, and changes in concentration.
To begin here is a gadget that may be useful as an addition to this introduction.
Let's Simplify: Temperature Changes
This is our Discussion on Temperature Changes.
Temperature:
If a reaction in Equilibrium is adjusted by changing the pressure the reaction will proceed depending on whether or not the temperatire is increased or decreased. So the first question you should ask yourself is... "Is the Temperature increasing or Decreasing?
If the temperature is Increasing, then the reaction will proceed in the direction that moves away from the heat in the reaction.
If the temperature Decreases, then the reaction will proceed in the direction that moves towards the heat.
One helpful way to think about it is like this: If the temperature decreases then you are cold and you want to move towards the heat. Conversely, if the temperature rises then you are really hot and you want to move away from the heat.
Temperature:
If a reaction in Equilibrium is adjusted by changing the pressure the reaction will proceed depending on whether or not the temperatire is increased or decreased. So the first question you should ask yourself is... "Is the Temperature increasing or Decreasing?
If the temperature is Increasing, then the reaction will proceed in the direction that moves away from the heat in the reaction.
If the temperature Decreases, then the reaction will proceed in the direction that moves towards the heat.
One helpful way to think about it is like this: If the temperature decreases then you are cold and you want to move towards the heat. Conversely, if the temperature rises then you are really hot and you want to move away from the heat.
Lets Simplify: Pressure and Volume Changes
Pressure is the inverse of Volume so If you understand how the dynamic equilibrium is altered by changes in pressure then you understand what occurs for changes in volume.
First thing you want to do here is remind yourself. Pressure only changes the amounts of the Gases in the reaction. Because of this only count the number of moles from the gases when following the next steps.
Step One: Count all of the moles of each of the gases in the reaction and add them up. Only add up what is on the left by itself and what is on the right by itself. When you get that answer, Identify which side of the equation has the higher number of moles of gases.
Step Two: Identify by looking at the question whether or not the pressure is increasing or decreasing.
Step Three: If the Pressure is increasing, the Dynamic Equillibrium will shift in the direction of the side of the reaction that has less moles.
Step Four: If the Pressure is decreasing, the Dynamic Equilibrium will shift in the direction of the side of the reaction that has more moles.
First thing you want to do here is remind yourself. Pressure only changes the amounts of the Gases in the reaction. Because of this only count the number of moles from the gases when following the next steps.
Step One: Count all of the moles of each of the gases in the reaction and add them up. Only add up what is on the left by itself and what is on the right by itself. When you get that answer, Identify which side of the equation has the higher number of moles of gases.
Step Two: Identify by looking at the question whether or not the pressure is increasing or decreasing.
Step Three: If the Pressure is increasing, the Dynamic Equillibrium will shift in the direction of the side of the reaction that has less moles.
Step Four: If the Pressure is decreasing, the Dynamic Equilibrium will shift in the direction of the side of the reaction that has more moles.
Let's Simplify: Concentrations
Finally let me help you solve problems based on what happens to the dynamic equillibrium when the concentrations of the products of reactants change.
For changes in concentration, the procedure is simple
First: Identify Whether or not the concentration is increasing or decreasing.
Second: The reaction will proceed in the direction opposite to the side at which the increase in concentration is on.
Third: The reaction will proceed in the same direction to the side at which the decrease in concentration is on.
Fourth: Remember that if the reaction proceeds in one direction or the other, all of the compounds on the side of the direction which the reaction will proceed goes up not just the one that changes.
For changes in concentration, the procedure is simple
First: Identify Whether or not the concentration is increasing or decreasing.
Second: The reaction will proceed in the direction opposite to the side at which the increase in concentration is on.
Third: The reaction will proceed in the same direction to the side at which the decrease in concentration is on.
Fourth: Remember that if the reaction proceeds in one direction or the other, all of the compounds on the side of the direction which the reaction will proceed goes up not just the one that changes.
Teacher Tube Video
Here's a great Video that might help you understand the explanations I just gave to you about
Le Chatlier's Principle:
Video
Sunday, March 8, 2009
Conclusion
Well thank you for visiting the Blog This week.
Tune in Next week for an examination of Kinetics.
Tune in Next week for an examination of Kinetics.
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