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Ms. Reynolds

MacArthur High School: (516) 434-7225

Ms. Reynolds

:

Kinetics and Equilibrium

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Kinetics and Equilibrium
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Chapter 8 Kinetics and Equilibrium Pages 136-151 in the text

 

Monday

Tuesday

Wednesday

Thursday

Friday

3/16

 

3/17

 

3/18

Lesson 1 

Collision Theory

1. Copy Notes 

2. Watch (2) videos

3. Complete Castle Learning Kinetics HW Lesson 1

 

 

3/19

Lesson 1 

Collision Theory - continued

1. Read pages 135-137

2. Complete questions 1-10

 

3/20

Lesson 2 

Potential Energy Diagrams

1. Copy Notes

2. Watch (1) video

3. Complete Castle Learning Kinetics HW Lesson 2

3/23

Lesson 2 

Potential Energy Diagrams -continued

1. Read pages 138-140

2. Complete questions 11-17

3/24

Lesson 3 

Equilibrium

1. Copy Notes 

2. Watch (1) video

3. Complete Castle Learning Equilibrium HW Lesson 3

 

3/25

Lesson 3 

Equilibrium - continued

1. Read pages 142-144 (top)

2. Complete questions 18-24

3/26

Lesson 4 

LeChatelier’s Principle 

1. Copy Notes

2. Watch (1) video

3. Complete Castle Learning Equilibrium HW Lesson 4

3/27

Lesson 4 

LeChatelier’s Principle -continued

1. Read pages 144-147

2. Complete questions 25 -30

3/30

Lesson 5 

Entropy & Enthalpy

1. Copy Notes 

2. Watch (1) video

3. Complete Castle Learning Entropy HW Lesson 5

3/31

Lesson 5

Entropy & Enthalpy continued

1. Read pages 148-149 

2. Complete questions 31-39 

 

 ***Q3 Castle Extra Credit due 3/25@ 11:59pm***

 

 


















Learning Targets

1. I can use the Collision Theory to explain how reactions occur. 
              To be an effective collision particles must collide with
                                          i.   Proper orientation
                                        ii.    Sufficient energy
2. I can identify factors that affect the rate of reaction as: nature of reactants (ionic faster), concentration (more of a substance, better chance for collisions), temperature (faster particles move the better the chance of collisions), surface area (powder always faster than block), catalyst (speeds up reaction without being used), pressure (only affects gases).

3. I can use Potential Energy diagrams to show energy and reactions (endothermic vs exothermic).

4. I can draw and identify
                                          i.   PE reactants
                                        ii.    PE products
                                       iii.    PE activated complex
                                       iv.    Activation Energy
                                        v.    Heat of Reaction
                                       vi.    Catalyst path

5. I can calculate the Heat of Reaction by subtracting the PE of the Products from the PE of the Reactants.
                 Negative value is exothermic
                 Positive value is endothermic

6. I can predict spontaneity of reactions using enthalpy (heat of reaction) and entropy (randomness or disorder in a system) because reactions tend to go toward LESS ENERGY and MORE DISORDER.

7. I can define an equilibrium reaction as one that takes place in a CLOSED system; one in which the Forward = Reverse RATES; one that has CONSTANT CONCENTRATIONS.

8. I can identify equilibrium reactions as PHASE, SOLUTION or CHEMICAL equilibrium.

9. I can identify stress in a system and use LeChatelier’s Principle to show how the system would adjust to the stress to reestablish equilibrium.  



Lesson 1

I:   Definitions

1)    Activation Energy:  the minimum amount of energy needed to produce an activated complex

2)    Heat of Reaction:  the amount of heat released or absorbed in a reaction  

3)    Exothermic Reaction:    a reaction that releases heat energy 

4)    Endothermic Reaction:   a reaction that absorbs heat energy 

5)    Activated Complex:        the temporary, unstable, intermediate union of reactants

6)    Equilibrium:   a dynamic chemical condition in which opposing reactions are proceeding at equal rates, producing an apparent constant condition.  

 

II:  Kinetics

A.   Chemical Kinetics deals with:

1)  The rates of chemical reactions   

2)  The pathway by which the reaction occurs (how the reaction occurs)  

 

Please watch the following video (~2 minutes):    https://www.youtube.com/watch?v=wbGgIfHsx-I​ 


B.   Collision Theoryin order for particles to react, they must collide with each other.  Each collision must have enough energy and hit in the right direction-they must be effective.​

Image result for rate of reaction

      A Reaction Rate depends on several factors: 

1)   The nature of the reactants: solutions of ionic solids react more quickly than non-ionic solids because ions are created.  Polar reacts more quickly than non-polar. 

Image result for collision theory nature of reactants ionic vs covalent                   Image result for collision theory nature of reactants ionic vs covalent​covalent


2)  The concentration of the reactants: the concentration ↑ the rate of the reactionFor gases, an increase in pressure brings the particles closer together and acts like an increase in concentration.

Image result for rate of reaction           Image result for rate of reaction


3)  Surface Area: ↑ surface area ↑the rate of the reaction.  A powdered substance will always react  faster than a solid of the same amount.

Image result for rate of reaction


4)  The temperature of the system: ↑ temperature ↑ the rate of a reaction.  Why?  Because more energy speeds up particles and increases the number of collisions.  The more collisions, the  more effective collisions, the faster the reaction. 

Image result for rate of reaction


5)    Presence of a Catalyst:  a substance that ↑ the rate of a reaction  without changing itself.  **Will not begin the reaction, it just lowers the required activation energy by providing a new pathway for reacting particles.    

Image result for rate of reaction


Please watch the following video (~5 minutes):   https://www.youtube.com/watch?v=OttRV5ykP7A&feature=emb_title​

HW:    1.  Please read pages 136-137 in the orange text book.

               2.  Please go to Castle Learning & complete 10 question Kinetics HW Lesson 1.  




Friday 3/20/2020 Assignment: 1.  Copy the notes (include diagrams) & watch video at bottom; 2. Complete Castle Learning 10 questions Kinetics Lesson 2 HW

Monday 3/23/2020 Assignment: 1. Read pages 138-140; 2. Complete questions 11-17 and submit a picture of your answers on remind.


Lesson 2


C.   Roles of Energy in Reactions

1)    Activation Energy:  the minimum energy needed to cause a reaction to begin

2)    Heat of Reaction (Enthalpy):  the difference between the potential energy of products and of the reactants 

 Formula:  ∆H = H products – H reactants  

*Reference Table I  shows the energy released/absorbed during a reaction*

Potential Energy Diagrams: illustrates the potential energy change that occurs during a chemical reaction.

aEndothermic Reaction:  reactions that  absorb  energy.  The potential energy of the products is greater than the potential energy of the reactants.  The sign for the Heat of Reaction (∆H) is positive.

Image result for endothermic potential energy diagram


b)  Exothermic Reaction:  reactions that release energy.  The potential energy of the products is lower than the potential energy of the reactants.  The sign for the Heat of Reaction (∆H) is negative.

Image result for exothermic potential energy diagram

 

  

Potential Energy Diagram with a Catalyst: *remember that a catalyst is used to speed up the reaction without being used itself. A catalyst will ONLY change the activation energy, not the potential energy of the reactants or the potential energy of the products so a catalyst will not change the heat of reaction!


Image result for potential energy diagram with catalyst

**The red curve shows the addition of a catalyst. 

Please watch this video **only up to 2:50 ( the remaining is material we do not need to cover)    https://www.youtube.com/watch?v=fEXq_RvnYgI​


 



 

Tuesday 3/24/2020 Assignment: 1.  Copy the notes (do not include diagrams) & watch video at bottom
2. Complete Castle Learning 10 questions Equilibrium Lesson 3 HW

Wednesday 3/25/2020 Assignment: 1. Read pages 142-144 (top); 2. Complete questions 18-24 and submit a picture of your answers on remind.

Lesson 3

III:  Equilibrium (sometimes referred to as dynamic equilibrium)

     Equilibrium is a condition that can occur only in a closed system.
Equilibrium is when the reactants become products and the products can return to reactants.
Equlibrium occurs when the rate of the forward reaction = the rate of the reverse reaction.
During equilibrium, the concentrations of the reactants and the products remains constant.
Equilibrium can be either physical or chemical.


Types of equilibrium:

1.  Physical Equilibrium

          A.   Phase Equilibrium:  When the rate of melting is equal to the rate of freezing; or when the rate of evaporation is equal to the rate of condensation.     H2O(s) <--> H2O(l)   or    H2O(l) <-->  H2O(g) 


Image result for phase equilibrium


          B.   Solution Equilibrium:  In a saturated solution (in a closed container), when all that can be dissolved in liquid has been reached, the rate of dissolving and the rate of recrystallizing are equal. C12H22O11(s) <--> C12H22O11(aq) 


Image result for solution equilibrium


2.  Chemical Equilibrium:  In a forward reaction, the reactants form products.  After a period of time the reactants begin to decrease and the products begin to increase.  At this point the reaction will reverse itself so the products become reactants. This will continue until the rate of the forward reaction = the rate of the reverse reaction.  CO2(g) + H2(g)​ <-->  CO(g) + H2O(g) 


Image result for phase equilibrium


Please watch the following video (~4 min)     https://www.youtube.com/watch?v=dUMmoPdwBy4 







Thursday 3/26/2020 Assignment: 1.  Copy the notes & watch video at bottom; 2. Complete Castle Learning 10 questions Equilibrium Lesson 4 HW

Friday 3/27/2020 Assignment: 1. Read pages 144-147; 2. Complete questions 25-30 and submit a picture of your answers on remind.

​Lesson 4

​​IV: LeChatelier's Principle ​​

 Le Chatelier’s Principle:  changes to concentration, pressure or temperature are known as  applied stresses.  This principle describes what happens to a system under such stresses.


Image result for seesaw

1)  Concentration Changes:  If there is an increase in concentration, the system will want to use up what has been increased, therefore the reaction will shift away from the increase.  If there is a decrease in concentration the system will want to create more of what was removed, therefore the reaction will shift towards the decrease.  At equilibrium, if you add more reactants, equilibrium is upset and must return to the value so equilibrium will shift to  the product side of the reaction

*put in more = shift to the other side       Add Away

*take out = remain on the same side      ​Remove Remain

 

​​2Temperature Changes

*look to see which side the heat is on, then follow the rule above: Add Away, Remove Remain  if heat is added on one side, shift away ​​from it;  if heat is removed from a side, remain on the same side


​​3Pressure Changes: **effects GASES** 

a)  Increase the pressure, the system will move to the side with  the fewest # of moles of gas (count the coefficients).

b)  Decrease pressure, the system will move to the side with the most # of molesof gas (count the coefficients).


4)  Effect of a Catalyst:  since catalysts will increase both the forward and the reverse reaction, there is  no change in equilibrium


What happens to everything else in the reaction?

​Everything on the same side of the equation does the opposite of the initial change.

Everything on the opposite side of the equation does the same as the initial change.​


Ex:   CO2(g) + H2(g)​ <-->  CO(g) + H2O(g) 

If there was an increase in the concentration of H2(g)​ then the equilibrium would shift to the right (ADD AWAY).

The concentrations of the other substances would change according to everything on the same side does the opposite (so CO2(g)  ​will decrease) and everything on the opposite side does the same (so CO(g) + H2O(g) will both increase)

***Click on this link to listen/watch as I go through a sample problem explaining how a system adjusts to stress. It will open as Power Point & you will have to play the slideshow (only 1 slide).  

record lechat example.pptxrecord lechat example.pptx

Please watch the following video (~4 min)    https://www.youtube.com/watch?v=XmgRRmxS3is​ ​​



DO NOT COPY THIS CHART

Image result for lechatelier's principle


Please watch the following video (~4 min)    https://www.youtube.com/watch?v=XmgRRmxS3is​ ​


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Monday 3/30/2020 Assignment: 1.  Copy the notes (include diagrams) & watch video at bottom; 2. Complete Castle Learning 10 questions Entropy Lesson 5 HW

Tuesday 3/31/2020 Assignment: 1. Read pages 148-149; 2. Complete questions 31-39 and submit a picture of your answers on remind.


Lesson 5 

V: Entropy and Enthalpy 

 

Entropy: (∆Srandomness or disorder in a system  ∆S solid > ∆S liquid > ∆S gas​

Image result for entropy



Enthalpy: (∆H) heat of reaction

Image result for enthalpy


Spontaneous Reactions:  one that occurs naturally under a given set of conditions. 

Gibbs Free Energy Change:  ∆G  tendency of a reaction to proceed to a minimum energy and a maximum entropy.   Least energy, greatest disorder. Whether or not reactions proceed seems to depend on the balance of two basic principles:

1)    The drive toward greater stability (reduced potential energy) -∆H  

2)    The drive toward less organization (increased entropy)  +∆S  

Image result for entropy vs enthalpy​  Naturally the ice cube will melt and the solid will become liquid

 

            Gibbs Free Energy Change Reaction:  ∆G = ∆H - T∆S

-∆G is Spontaneous

For a reaction to occur spontaneouslymore likely exothermic reactions with an increase in entropy

 

           Please watch the following video (up to 4:02 min - we do not need to do the calculations; watch the whole video if you are going to take AP or College Bio as you will be doing the calculations)  

           https://www.youtube.com/watch?v=8N1BxHgsoOw   

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