AcidsBases _amp; Organic Chemistry; KineticsEquilibrium by dffhrtcv3

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									Kinetics/Equilibrium;
Acids/Bases & Organic
      Chemistry

       Welcome
          To
    The GowerHour
       Unit 12 (Chapter 18): Chemical Kinetics

I. Chemical kinetics: The study of reaction ______( ________ of
                                              rates   Speed
     reaction).
A. Factors that influence the reaction ______.
                                       rate
1. _______________ of reactants.
   Concentration
2. Nature of the reaction (Amount of _________________).
                                       Activation energy
3. _________________
    Temperature
4. Reaction mechanism
5. Presence of a __________.
                  catalyst
B. Collision Theory
                                    collisions        reactants
1. Reactions occur when there are ________ between __________.
2. BUT...not all __________ lead to a reaction.
                  collisions
                                oriented            geometry
a. Molecules must be properly ________ (collision___________).
   Example: CO + NO2 → CO2 + NO
     O                                       O
      C           Ineffective                  C      Effective
           N O collision                          O collision
                                                 ON
           O
                                  kinetic energy KE
b. Only molecules with enough _____________(_____) to break the
    bonds                    reaction
   _______ will result in a __________. (KE > Ea)
                        KE                     bounce
c. Molecules with low _____ (KE < Ea) will _________ off of each
           No reaction
   other (____________).
C. Activation Energy (EA)
1. Always a _________quantity.
               positive
2. Depends on the ________ of the reaction.
                     nature
                    Low
a. Fast reaction = _____EA
                     High
b. Slow reaction = ______EA
3. Independent of ______________ and _____________.
                    concentration        temperature
4. Catalyst _________ EA without being __________ in the
                lowers                    consumed
     reaction.
5. Diagram of activation energy
                                     w/ catalyst (Lowers EA)

                                     products
            E                             Activation energy (EA)

                 react
    E = energy
                   rxn progress

   E = energy             *           * = Activated complex
                 react
                                      Activation energy (EA)
            E                         w/ catalyst (Lowers EA)
                                  products

                   rxn progress
                        intermediate
6. Activated complex = ____________ between reactants and
   products (________________)
              Pseudo-molecule
7. Example of activated complex: CO + NO2 → CO2 + NO
          Reactants
     O C + O N O

      Activated complex
     O C      O     N O
         = partial bond
        Very Unstable

               Products
     O    C    O+ N O
D. Reaction Rate and Temperature
                          
  As temperature __, rate __ (in general)


                                                 T2 > T1
                                                 Average KE increases w/
  # of                                           temperature
molecules                                        More molecules have
                                                 KE > EA at higher T
                                            T2
                                            T1
                              EA
                   KE

 **Activation Energy is a fixed amount, independent of temperature
E. Collision Theory--Qualitative effects:
1. particle size
size ; surface area ; collisions ; rate 
 As the size of the particle , the rate 
2. temperature
   T ; KE ; the # of molec. w/ min energy ; rate 
  As the temperature , the rate 
3. catalysts
 As the EA , the rate 

4. concentration
   concentration ; the # of molec.; the # of collisions ; rate 
  As the concentration , the rate 
F. Reaction rate: A positive quantity that expresses how the
                   Molarity
   concentration (_________) of a reactant or product changes with
   ______.
    time       [X] = concentration of X (M)
               X                                  mol/L·s
                                     Units of Rate: _____________
      Rate 
               time

1. Example:     2 N2O5 → 4 NO2 + O2
   Reactants decrease () over time, products increase (+) over
   time.
               N 2O5   NO2   O 2 
  rate =                          
                2  t      4  t   1  t
                                                        coefficients
2.   2 N2O5  4 NO2 + O2


                                  [NO2]
            4



Conc        2
(M)

            1                     [O2]


            0                     [N2O5]
                           Time
H. Reaction Mechanism: Sequence of steps by which a reaction
   occurs on the __________ level (like Hess’ Law)
                  molecular
1. Example: CO + NO2  CO2 + NO

      1.     NO2 + NO2  NO3 + NO          Elementary step
      2.     CO + NO3  CO2 + NO2          Elementary step

 Overall:    CO + NO2  CO2 + NO
2. Rate determining step:          slowest
                            The _________ step in the reaction
   mechanism.
a. Example:           AB         fast
                      BC         fast
                      CD         slow  Rate determining step!
       Overall rxn: A  D
                     
       Overall rate ______ Rate of the slowest step.




   E
          A      B       C   D

                     Rxn
II. Equilibrium
A. Reversible Reactions: Reactions that do not go to ___________.
                                                     completion
Example: 1. H + I → 2 HI
               2  2
                                      pink        clear
          2. Phenolphthalein (ph) ph+ + H+ → ph-H+
                                                   exothermic
Example: Rechargeable battery

  Pb + PbO2 + 2 H2SO4 → 2 PbSO4 + 2 H2O + energy
                                      Add electricity & the
                                      rxn will reverse
B. Equilibrium system: The ________ and _______ reactions occur
                             forward       reverse
                                   _____________
  at the same ____(______) and the concentrations of reactants and
              rate speed
  products remain _________.
                  constant
                      Rateforward = Ratereverse
C. Equilibrium is a dynamic process: At equilibrium the
   _________ and _______ reactions are still occurring
    forward        reverse
    dynamic                                            constant
   (_________), even though the concentrations remain _________.
   Example: changing classrooms

   Concentration of reactants + products do not need to be
   equal ….. only the rates!

                                                       equilibrium
D. Stresses alter equilibrium: When a system is at ____________,
                                          changes
    it will stay that way until something ________ this condition.
    Stresses: (1) temperature
                (2) concentration
                (3) pressure
E. Le Chatelier’s Principle: When a system at equilibrium is
   disturbed by applying a ______, a new ____________ position is
                            stress        equilibrium
                relieve
   attained to _______ the stress.
1. Temperature effects on equilibrium
   Example:
        2 NO2 → N2O4 + 58.8 kJ          (exothermic)

                                              heat
  (a) STRESS: Raise temperature (addition of ______)

       Equilibrium is shifted ____.
                               left

  (b) STRESS: Lower temperature (removal of ______)
                                             heat

                               right
       Equilibrium is shifted ______.
2. Pressure effects on equilibrium: When pressure is
    __________, the stress is relieved by favoring the reaction
     increased
    with _______ gas molecules (fewer gas molecules = ______
         fewer                                            lower
    pressure).
    Example:
             2 NO2 (g) → N2O4 (g)

(a) STRESS: Increase pressure
    2 molecules on left, 1 molecule on the right (lower pressure)
    Equilibrium is shifted _______.
                            right       (fewer gas molecules)

(b) STRESS: Decrease pressure
     Equilibrium is shifted ______. (greater # of gas molecules)
                             left
3. Concentration effects on equilibrium:
Example: Acid/Base indicator
[Ni(H2O)6]2+ + 6 NH3 → [Ni(NH3)6]2+ + 6 H2O
  green                   blue
(a) STRESS: Add NH3
    Need to remove NH3
                        Right (blue)
Equilibrium is shifted _____________.

(b) STRESS: Add H2O
    Need to remove H2O
Equilibrium is shifted _____________.
                        Left (green)
F. Applications of Le Chatelier’s Principle
1. Glasses / Sunglasses
       Reaction:      AgCl + energy → Ag + Cl
                      clear             dark
STRESS: Add sunlight  energy, shifts right, glasses become dark.
STRESS: Remove sunlight energy, shifts left, glasses become clear.
2. Biochemical Equilibrium System (Respiration)
       Reactions: CO2 + H2O → H2CO3
 CO2 formed                    H2O
 during respiration     H2CO3 → H+ + HCO3-
                              More CO2 produced
STRESS: Exercise vigorously __________________)
Both rxns shift right. [H+]  (Acid) causing pH  (acidic) 
the brain sends a message to exhale more rapidly.
                         exhale CO2
STRESS: Breathe faster (___________)
 Less CO2, Rxns shift left, [H+] , & pH returns to normal.
3. Hyperventilating (See above reactions)
                              exhale a lot of CO2
   STRESS: Exhale rapidly (_________________)
    Rxn shifts left, pH  (alkaline), body responds by
    constricting blood vessels (dizziness).
                               Breathe in exhaled CO2
   STRESS: Breathe into bag (_______________________)
     Rxn shifts back to the right.
4. Altitude Sickness
   Reaction:    Hb + O2 → Hb–O2
            (Hemoglobin)          (Oxygen circulates in blood)

  STRESS: Lower pressure (________________________)
                                Lower concentration of O2
   Rxn shifts left (less O2 to brain/body, which leads to dizziness,
   nausea, & headache)
   STRESS: Increase hemoglobin production (Acclimation)
 Body adjust by producing hemoglobin, shifting the rxn back to
 the right, more O2 circulates in body.
G. How is equilibrium measured? Equilibrium Expression
1. Keq = Equilibrium constant (No Units)
           Concentration
   (a) Kc (_____________); Used for solutions (aq) or gases. (b)
   (b) Kp (________); Used for gases only.
           Pressure
2. Equilibrium Expression
   Reaction: aA + bB  cC + dD
                                                   c      d
            [products]                       [C] [D]
     K eq                            K eq     a    b
            [reactants]                      [A] [B]
                                                   Kc
                           equilibrium
(a) Concentrations are at____________. (Not _____ concentration)
                                               initial
(b) Concentration =             mol / L container
                             Some books call this Molarity!
                      L     S                           negligible
(c) Amount of pure __ or __ consumed in a reaction is _________, so
                                Equilibrium expression
   they are not included in the ____________________.
   Example: Calculate the molarity of 1.00 L of water.
Intensive                            1000 g x 1 mol
                   1.00 L = 1000 g                         = 55.5 mol
property: depends                                 18.02 g
                                                             55.5 mol
upon density!                              Large!         M
 (d) Meaning of equilibrium constant:                           L
                                       forward
 1. Keq > 1 : Products are favored. (________ reaction)
              ________
2. Keq < 1 : _________ are favored. (_______ reaction)
              Reactants                reverse
(e) What does a Keq of 1.0 x 1030 mean? 1.0 x 10-30?
      Products >> Reactants                Reactants >> Products
        (Almost complete)
3. Example: (a) Write the equilibrium expressions,
   Kc, for the following reaction:

          2 NO2(g)  2 NO(g) + O2(g)
                        2
                  [NO] [O2 ]
             KC         2
                   [NO2 ]
4. Example:            PCl5(g)  PCl3(g) + Cl2(g)
   For the above reaction, the equilibrium constant is 35. If the
   concentrations of PCl5 and PCl3 are 0.015 M and 0.78 M
   respectively. What is the concentration of Cl2?
         [PCl 3 ][Cl 2 ]
  K eq 
           [PCl 5 ]

        (0.78)[Cl2 ]
   35                               [Cl2] = 0.67 M
           0.015
H. Calculating equilibrium concentrations from initial concentrations:
Steps in calculating equilibrium concentrations:
(1) Write equilibrium expression
(2) Calculate change in concentration of each substance
(3) Calculate equilibrium concentrations

Example #1: Given the following reaction: A  B + C. The initial
    concentration of A is 0.260 M and at equilibrium, [C] is 0.160 M.
    Calculate the Kc.
     Kc = ?                   A                B       +       C
Initial (M)                0.260                0               0
Change (M)                  x                + x            + x
                          0.160             + 0.160        + 0.160
Equilibrium (M)             0.100              0.160          0.160
                                   2
          [B][C]        (0.160)
     Kc                                = 0.256
            [A]           0.100
Example #2: Given the following reaction:
        H2(g) + I2(g) ↔ 2 HI(g).
  At 25°C, 0.100 mol of H2 and 0.100 mol of I2 react in a 1.00 L
  container. At equilibrium, the [H2] is 0.080 M. Calculate Kc at
  this temperature.
                           M = mol / L
                          H2          +      I2         2 HI
   Initial (M)            0.100             0.100           0
   Change (M)            x                  x           + 2x
                        0.020              0.020       + 0.040
   Equilibrium (M)        0.080              0.080         0.040

                 2
        [HI]            (0.040)   2
  Kc                                    = 0.25
       [H2 ][I2 ]       (0.080)   2
                          I. Polymers
I. Polymers: A polymer is a compound with a repeating unit, called a
      ___________, and contains a ______ molar mass.
       monomers                    high
A. Types of Polymers
1. Natural polymers:
                polyisoprene
(a) Rubber (______________)
(b) Biological compounds:
(i) Proteins
(ii) Nucleic acids (DNA & RNA)
(iii) Cellulose
(iv) Starch
2. Synthetic polymers:
(a) Nylon
(b) Polyester
(c) PVC
(d) Plexiglass
                      B. Reaction Types
1.   Addition reaction: One molecule _____ to another molecule.
                                     adds
     Monomer: _________
                ethylene
     H                    H
            C      C
     H                    H
     Example:         Polyethylene

     C      C     C      C      C     C      C     C

     C      C     C      C     C      C     C     C
                      Addition Reaction

         Vinyl chloride
Monomer: _____________
   H                    H
          C     C
   H                       Cl
  Example:                        PVC
              Polyvinyl chloride (____)

   C     C      C      C        C    C    C    C
         Cl           Cl            Cl         Cl

   C     C      C      C        C   C     C   C
         Cl           Cl            Cl        Cl
The simple repeating unit of a polymer is the monomer.




Homopolymer is a polymer made up of only one type of
monomer
 ( CF2   CF2 )n       ( CH2    CH2 )n       ( CH2    CH )n

     Teflon             Polyethylene                 Cl
                                                 PVC
2.                             H2O
     Condensation reactions: A ____ molecule is formed in the
     reaction.
                                         · H
     Amine group (amino): NH2 or N H
                                         ·           O
    Carboxylic acid group (carboxyl):        COOH or     C    ·
                                                              O    H
                                                              ·
                                                              ·
Example:     Polyester                                        ·
      O          O
H    · C
     O                   C
                             ·
                             OH + H          O   CH2   CH2    OH
     ·
     ·                       ·
                             ·
     ·                       ·
                   H2O           Dehydration synthesis vs Hydrolysis

                   O             O
           H   · C
               O                    C    ·
                                         O   CH2   CH2   OH
               ·
               ·                        ·
                                        ·
               · ester                  ·
                                    ester
Example: Proteins (Alanine + Glycine)
    Alanine              Glycine
     H O                   H O
H2N C C OH + H2N C C OH
     CH3                   H
              R group           H2O     (Dehydration Synthesis)


               Peptide bond
           H O    H O
    H2N C C N C C OH + H2O
           CH3   H H
Amino acids are the basic structural units of proteins. An amino
acid is a compound that contains at least one amino group (-NH2)
and at least one carboxyl group (-COOH)

Peptide bond = _______ group : ______________
                  amide        carboxyl group
              2
dipeptide = ___ amino acids
tripeptide = ___ amino acids
               3
                 many              protein
polypeptide = ______ amino acids = _______
Example: Glycogen, cellulose, and starch (Polysaccharides)
Monomer: _________
          glucose
Complex carbohydrates
        CH2OH

         C      O

   C                 C          or
         OH
 HO      C      C     OH
                OH
Glycogen: Animals store energy in the form of glycogen & turn it
back into glucose as needed.
Cellulose: The most common organic compound on Earth (ie. cotton)




                  Hydrogen Bonds (Cross-linking)
 Plants use cellulose for strength. The cellulose chains are all
 stretched out, and like to stay right next to each other, like raw
 spaghetti that's all stuck together. That's why cellulose can hold up
 the tallest trees!
Starch:




                              Starch is a compact way to store a
                                 lot of glucose in a small space.
                                 Our bodies break the starch
                                 down into glucose, which can be
                                 used for energy.

Even though starch and cellulose are both made from the same sugar
(glucose), they act very differently (because the glucose molecules
are joined together differently). Starch will dissolve in water, but
cellulose won't. So we make food from starches and we build things
and make clothing out of cellulose.
                      Acids & Bases
A.    Properties of acids and bases:
1.    Acids                            2. Bases
(a)   Sour                             (a) Bitter
(b)   Changes the color of acid-       (b) Changes the color of acid-
      base indicator.                      base indicator.
(c) Some react w/metals                (c) Slippery
(d) React w/bases to form salts        (d) React w/acids to form salts
(e) Conducts electric current          (e) Conducts electric current


               Blue Litmus Paper: Blue to Red Acid
               Red Litmus Paper: Red to Blue Base
B. Bronsted-Lowry Acids and Bases
1.   Acids: H+ ________
                Donor
     Example:                                List of strong acids:
       HCl (aq)       H+    + Cl            HNO3, H2SO4, HCl,
       HCN (aq)       H+   + CN            HClO4, HBr, HI

2.   Bases: H+ ________
               Acceptor                      List of strong bases:
                                             LiOH, NaOH, KOH,
     Example:                                Ca(OH)2, Ba(OH)2,
       OH + H+             H2O              Sr(OH)2
        CN + H+           HCN
3.                                              acid       base
     Amphoteric substances: Can behave like an _____ and a _____.
     Example:                  H+
                  H+
        H2CO3  HCO3  H+ + CO32
        Contains both a H+ and  charge.
C. Acid-Base Reactions (Conjugate acid-base pairs)
                         (CA)                (Differ by only a H+)
1. HNO2 + ClO  HClO + NO2
                                    (CB)
     Acid     Base
                           (CA)
2.   H2SO3 + OH          H2O     + HSO3 
                                           (CB)
     Acid     Base
                           (CA)
3.   H2CO3 + BrO2  HBrO2 + HCO3
                                           (CB)
     Acid    Base
                                                  (CA)
4.   H3PO4 + C2O42       H2PO4      + HC2O4
                            (CB)

     Acid     Base
                             C. pH Scale:                              NaOH
                                      N                                 Lye
                                      e
H2SO4                                 u
                                      t
                                      r
                                      a
                                      l




        Acidic                                             Alkaline/Basic
0   1      2     3   4   5      6     7       8   9   10    11   12    13     14


                                     High
                                    quality
                                     H2O
                         Acid
                         Rain
D. In impure water (contains an acidic or basic substance):

       If [H+] > 1.0 x 10-7 M, solution is _______.
                                           acidic
       If [H+] < 1.0 x 10-7 M, solution is _________________.
                                           basic or alkaline
       If [H+] = 1.0 x 10-7 M, solution is _________.
                                           neutral
       1.0 x 10−7 = pH 7 
                                          1.0 x 10−2 = pH 2
       pH < 7 = acid
       pH > 7 = base
                                          1.0 x 10−5 = pH 5
       pH = 7 = neutral

                                          1.0 x 10−11 = pH 11
The End !!!!

								
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