The document provides an outline and notes on the topics of rate of reaction, collision theory, factors affecting reaction rates, activation energy, endothermic and exothermic reactions, equilibrium, and Le Chatelier's principle. Key points include: - Reaction rates can be determined by measuring how quickly reactants are used up or products are formed. Temperature, catalysts, surface area, and concentration can impact reaction rates. - Collision theory states that reactants must collide with sufficient energy and correct orientation for a reaction to occur, forming an intermediate activated complex. - Equilibrium is reached when the rates of the forward and reverse reactions are equal, though concentrations of reactants and products may not be equal. -

1. Rate & equilibrium

2. Outline:
•Rate
•Reactions & collision theory
•Graphs w/ activation energy of endo & exo
•4 factors that affect rates of reaction
•Read chapter 17
•Students should take notes & copy
diagrams (might have space after vocab)

3. Sample notes
• What is rate?
• What factors affect rate?
• What is collision theory?
• Samples of exothermic and endothermic
graphs of reaction rate

4. Lab/demos
Zinc in HCl, 2 concentrations, Zn,
different surface areas, matches
WHEN is it done?
Catalyst demo (shows activity complex*)
Heat 300 ml ofA to 80C then add 100 mlH202 observe then add 30 ml of catalyst CoCl2
Surface area bottle

5. What is rate?
• Describe these rates:
– When we light a match
– We put zinc in HCl (2 different concentrations)
• How do we know when the reaction is
done?

6. Rate of reaction
• can be determined by
measuring the rate at which
reactants are used up or the rate
at which products are formed.

7. • A would be increasing rate: likeexplosive (gun powder)
• B is a constant rate (like how soaps work)
• C is slowing down, like what refrigerators would do
• KEY: Chemists work on controlling rates.
Discuss rates at
various points.

8. Collision theory
• Reactants have to strike each other with
sufficient energy and in the correct
configuration in order for the reaction to
occur.
• Kicker will share an example of students at a dance.
• Reactants must hit with:
– 1. sufficient energy
– 2 correct config. Or orientation
• In order for a reaction to progress.

9. Consider a simple reaction involving a collision
between two molecules - ethene, CH2=CH2, and
hydrogen chloride, HCl.
These react to give
chloroethane.
As a result of the
collision between
the two molecules,
the double bond
between the two
carbons is
converted into a
single bond. A
hydrogen atom
gets attached to
one of the carbons
and a chlorine
atom to the other.

10. During a reaction
• An intermediate particle is formed. It is
neither reactants nor products. This
happens when there is enough energy &
proper orientation of the reactants. This is
called an activated complex. This is an
intermediate that does not stick around
long.
See catalyst demo & color change!

11. Discuss activation
energy
See page 597 graph.
What causes paper to
burn?
Kicker will burn some paper
and discuss the graph it
would make.
Wave it in the air, rub it like
two sticks, then use a
heat source

12. Activation energy

13. The activation barrier must be crossed before reactants
are converted to products. The activated complex is a
temporary arrangement of particles that has sufficient
energy to become either reactant or products.

14. ∆T
∆T

15. Class Question

16. This is an exothermic reaction. The products have
less energy than the reactants. But it took a lot of
activation energy to get it going. Most of these
reactions are self sustaining as they have enough
energy to keep going.

17. This is an endothermic reaction. The products have more energy than the
reactants. These reactions are not self-sustaining because not enough
energy is released to keep the reaction going. Endothermic reactions need a
constant supply of energy to keep going.
Some examples are ice melting, evaporation, photosynthesis

18. Photosynthesis
• CO2 + H20 + light --> C6H12O6 + O2

19. SAMPLE QUIZ ?s
What do you have at A,
B, & C. What is D? Is
this exo or endo?

20. I get this, but how
can we control the
rate of the reaction?

21. 4 methods of increasing the rate
of reaction.
• Temperature
• Catalyst
• Surface area
• Concentration.

22. Temperature
• If temp. increases, kinetic energy increases and
so do the number of collisions.
– If temperature decreases, the opposite is true
• A 10 C increase in temp will approximately
double the rate of reaction
• A 30 C increase will cause an increase in rate of 8
times faster. (note that it is exponential)

23. Catalyst• This is a substance
which changes the
rate, without
undergoing any
permanent chemical
change itself. It does
this by lowering the
activation energy by
allowing a a different
path for the reaction
to occur.

24. Write this reaction
• The rate of the decomposition of hydrogen
peroxide (dihydrogen dioxide) into water
and oxygen gas can be increased by adding
the catalyst manganese dioxide. (Put the catalyst
above the arrow)

25. Video of how this catalyst works.
H2O2 MnO2 u ruuuuuu H2O + O2

26. Kicker will draw another example

27. Which of these could use the
help of a catalyst?

28. Summary

29. Some reactions are simply faster
because of the nature of the
substances.
• Ions in solution can react faster
• AgNO3 + Cl- --> AgCl (s)
• Covalent with covalent are usually slow because
you have to break tough bonds before other bonds
can form.
• N2 + H2 -->NH3
• Br2(l) + C6H11 (aq) --> C6H11Br + HBr

30. Assignment
Do pg 3 NOW
Assign pg 4 & 5 in packet
Read pg 595-600 & 626
Read Iodine Clock Lab in packet pg 6
(get ONLY 80 ml each A & B)
WE will DEMO temp.

33. Assignment
• You need to read equilibrium pages in our
book
• Pg 601-604 & 612-619*ignore math for now, we’ll do that later
• DO pg 628 # 4, 5, 6, 8, 9 & study for a quiz

34. Reversible Reactions &
equilibrium
Lecture reversible reactions, equilibrium &
shifts.
BE SURE YOU HAVE READ PG 601-604

35. Use the worksheet as notes
Equilibrium Ch 17
Review rate… How is it measured?
2Zn + 2HCl --> H2 + 2ZnCl
Collision theory
Factors affecting rate

36. 1. gas given off -
Mg + 2HCl → McCl2 + H2(g)
2. insoluble product is formed -
AgNO3(aq) + KCl(aq) → KNO3(aq) + AgCl (s)
3. molecular product formed -
HCl(aq) + NaOH(aq) → NaCl(aq) + HOH (L)
DO YOU REMEMBER double displacement when there
was no reaction.
Most reactions are irreversible, that is, they go
to completion.

37. Equilibrium is the
• State at which the concentration of all
reactants and products remain constant.
– See pg 602

38. These equilibrium rxns. Are
reversible
A + B C + D
A + B C + D is forward rxn
C + D A + B is reverse rxn
If A + B is forming C + D as fast as C + D is
forming A + B, the reaction is at equilibrium.
The rate forward and backward is equal.
• NOTHING SAYS THAT THE
CONCENTRATIONS ARE EQUAL THOUGH!

39. Demo… shake clear--->blue
– WHAT AM I DOING TO MAKE IT GO?
– As we agitate it it becomes oxygenated. This shows reversibility

40. At equilibrium,
• it appears as if nothing is happening, but
reactants are still forming products and
products are forming reactants at the same
rate.
• NOTE: The concentration of P & R are not
necessarily equal. Long arrow points to
where you have more.

41. See diagram 603

42. See worksheet graphs
– Graphically. See pg.
– Look carefully at the axis.
– Why do some come down? (green & purple)?

43. Test Tube & Straw Device
• When are we at equilibrium?
• PG 602: EQUILIBRIUM: a dynamic state
where the concentrations of the R and P
remain constant over time, as long as
conditions are not changed. (such as
pressure, temp, # particles)

44. Which do we have more of?
• H20 + HC2H3O2 H3O +
+ C2H3O2
-1
• H20 + HClO4 H3O +
+ ClO4
-1

45. • Discuss INDUSTRY. This is only 78.2%
complete, What if I want to make more
• H2+ I2 2HI

46. Homo Vs Hetero
• Homogenous all the same state of matter
• Heterogeneous P & R are in different states
of matter.
• Just and FYI in case you hear about these in
your reading.

47. Le Chateleir’s principle.
IF STRESS IS APPLIED TO A SYSTEM IN
DYNAMIC EQUILIBRIUM, THE SYSTEM
CHANGES TO RELIEVE THE STRESS.
“Things move in the direction that relieves the stress”
or
“the system rolls with the punches”

49. Shifts (see worksheet)
• Concentration (soln. &gases only)
• More, concentrated will shift to make more.
• See Pg 612-613
• Removing a product always pulls the
reaction toward the product.
• “Removing something, pulls it that way!”

50. Temperature (soln & gases)
A + B + heat C
endothermic in the forward direction
A + B C + heat
exothermic in the forward direction
Adding heat favors the endothermic reaction. WHY?

51. DEMO
• 2NO2 (g) N2O4 (g) + heat
• N2O4 is clear
• The reverse reaction is
endothermic.
• LET’S TRY COOLING IT, HEATING IT

52. Pressure and volume (for gases only)
2A(g) + B(g) 2C(g)
• A change in pressure affects only a system
that has an unequal number of moles of
gaseous reactants and products.
• If you have more pressure the system will
adjust to take up less space. (pg 617)

53. Increase pressure

54. In the Haber process (pg 612)
N2(g) + 3H2 (g) 2NH3 (g) + heat
1. Adding heat will do what?
2. Adding pressure?
3. Removing pressure?
4. Removing product?
5. Adding reactant?

55. Try worksheet examples

56. Try these
• Pg 615 ex 17.4 then exercise #17.4
• Pg 617 ex 17.5 pg 618 exercise 17.5
• Pg 619 ex 17.6 exercise 17.6

57. LAB
• This is on page 13 & 14 of your packet

58. Keq lecture pg 605-610, 620-
• Keq is a value the tells us which direction a
eversible reaction is favored. Toward
products or toward reactants.
• USE HANDOUT first in packet, then see ppt.)
– Book probs.pg 628… 18-21, 38-42, 65, 68, 59
– Know what Keq values mean!
– Be able to write expressions & do calculations
for Keq. (look ahead at Ksp)

61. Solids(s) & liquids(l) are NOT included.

63. • PRACTICE: 1. Calculate the Keq for
this reaction given the concentrations at a
constant temperature are as follows:
[NO2] = 8.8 M [NO] = 1.2 M [O2] = 1.6 M
2NO(g)+O2 (g) 2NO⇌ 2 (g)

64. • PRACTICE: 2. write the equilibrium
equation for this reaction:
2Na(s)+CuCl2 (aq) Cu⇌ (s)+ 2NaCl(aq)

65. • PRACTICE: 3. Calculate Keq for the
above reaction (practice 2) if the
concentrations are as follows:
[CuCl2] = 0.050M & [NaCl] = 0.50M
2Na(s)+CuCl2 (aq) Cu⇌ (s)+ 2NaCl(aq)

66. SO WHAT DO Keq VALUES MEAN?
• Recall that the equations for Keq is a fraction. So, if the value of Keq >
1 (greater than 1), then that means the numerator is larger than the
denominator. So which direction would be favored in the reaction?
___________ (product or reactant?)
• Keq >1 favors products of forward reaction
• Keq<1 favors reverse reaction (reactants)

68. YOU TRY THIS ONE

69. WORK THRU PRACTICES IN PACKET

72. How does as shift affect Keq
• Shifts in pressure or quantities do NOT
change Keq
• Shifts as a result of temp change do affect
Keq

73. Book probs.
• Pg 606 17.1
• Pg 610 17.3
• Pg 611 1, 2 & 5
• Pg 619 17.6

74. You may see this. . . Ksp
(pg 622)
• This the the constant of solubility we write
these the same way.

75. Assignment
Worksheets & BOOK QUESTIONS on your
own paper to turn in tomorrow!
Practices in packet
Pg 629..: 18-21, 29, 31,
32, 33, 34, 38-42, 65, 68,
(59 challenge)

76. Work on problems
• Remainder of Quick reviews by tomorrow
• Rate /equilibrium quiz
• Still: Nuclear information