1. Wednesday February 17, 2016
Identify one way to change the speed of a reaction.

2. Rates of Reaction and Collision Theory
A chemical reaction involves a collision between particles.

3. How do we make the reaction go faster?
There are four things that we can change to make the reaction go faster.
They are
Temperature
Surface area
Concentration
Using a catalyst

4. Inquiry Lab Activity
Test the affects of temperature, surface area, and concentration on the rate of reaction.

5. Using a catalyst
A catalyst is a chemical added to a reaction to make it go faster.
It gives the reaction the energy to get started

6. How do we make the reaction go faster?
There are four things that we can change to make the reaction go faster.
They are
Temperature
Surface area
Concentration
Using a catalyst

7. Thursday February 18, 2016 Answer this text:
No, a catalyst lowers activation energy. The reaction speeds up bc it takes less energy to start.

8. Thursday February 18, 2016 Sticky Note summarizing activity
EQ: What factors affect reaction rates?
Complete other two stations
Be sure to write information from the blue folders in the Notes/Discussion sections
Sticky Note summarizing activity
ANNOUNCEMENTS:

9. Sticky Note Summary
Write one thing you learned about your assigned factor on your sticky note.
Birthday!!
January-March: CATALYST
April-June: CONCENTRATION
July-September: SURFACE AREA
October-December: TEMPERATURE

10. Monday February 22, 2016
Explain how powdered pain medication is said to “work faster” than pill pain medication.

11. Surface area
Making the pieces of the reactants smaller increases the number of particles on the surface which can react.
This makes the reaction faster.
The particles on the surface can react
When cut into smaller pieces the particles on the inside can react

12. Writing Task Collision Theory Factors Affecting Rate: Temperature
Concentration
Surface area
Catalyst

13. Senior Level Science Course Options
Anatomy
Physics
AP Chemistry
AP Physics
AP Biology
AP Environmental Science

14. Concentration There are more particles in the same volume to react
So the reaction goes faster.
There are less red particles in the same volume so there is less chance of a collision
There are more red particles in the same volume so there is more chance of a collision so the reaction goes faster

15. Temperature
An increase in temperature gives the particles kinetic energy
This means they collide with other particles more often
So the reaction goes faster.

16. Tuesday February 23, 2016
Based on your previous lab experiences, would you expect the temperature of an
Endothermic reaction to increase/decrease
Exothermic reaction to increase/decrease
EQ: Which of today’s lab reactions is
Endothermic?
Exothermic?

17. Thermodynamics Lab Demonstration
Hot pack
Cool pack
Background
From this lab, you will develop an understanding of exothermic and endothermic reactions and how to use these two types of chemical reactions for a practical application.

18. Thermodynamics Lab Demonstration
Exothermic
Endothermic

19. Thermodynamics Lab Procedure (CaCl2): Repeat with the NH4Cl
Measure and crush 5 g of CaCl2
Measure 50.0 mL of water in a beaker.
Measure the initial temperature of the water
Pour in the crushed CaCl2 into the water and immediately begin timing.
Record the temperature of the water every 15 seconds for a total of 3 minutes or until the temperature stays the same for 5 trials.
Repeat with the NH4Cl
Pre Lab First!

20. Thermodynamics Lab Demonstration
DATA COLLECTION
For each reaction, record the temperature of the water every 15 seconds in the table below.
Graph your data.
Label the horizontal x-axis “time” and
The vertical y-axis “temperature”
Plot one line for calcium chloride (CaCl2) and one line for ammonium chloride (NH4Cl)
Make each line a different color
Title your graph and make a key

21. calcium chloride (CaCl2) ammonium chloride (NH4Cl)
Time (min:sec)
Temperature (˚C)
0:15
0:30
0:45
1:00
1:15
1:30
1:45
2:00
2:15
2:30
2:45
3:00

22. Wednesday February 24, 2016 EQ: What factors affect reaction rates?
Lab Discussion
Reaction Equilibrium
Le Chatelier’s Principle
ANNOUNCEMENTS:

23. Lab Conclusions
Which of the chemicals would be a good candidate for making a hot pack? Why?
Which of the chemicals would be a good candidate for making a cold pack? Why?
Which one is exothermic? Endothermic?

24. Chemical Equilibrium

25. Chemical Equilibrium
Some reactions are reversible:
N2O4 (g)
2 NO2 (g)

26. A System at Equilibrium
Once equilibrium is achieved, the amount of each reactant and product remains constant.
N2O4 (g)
2 NO2 (g)

27. The Equilibrium Constant

28. The Equilibrium Constant
For equation:
aA + bB
cC + dD
The equilibrium expression is:
Keq =
[C]c[D]d
[A]a[B]b

29. What Does the Value of K Mean?
If K > 1, the reaction is product-favored; product predominates at equilibrium.

30. What Does the Value of K Mean?
If K > 1, the reaction is product-favored; product predominates at equilibrium.
If K < 1, the reaction is reactant-favored; reactant predominates at equilibrium.

31. of the forward and reverse reactions are the same.
For a reversible reaction at chemical equilibrium:
The rate…
of the forward and reverse reactions are the same.
The concentration of the substances…
are not necessarily equal, but stay constant.

32. Le Chatelier’s Principle

33. A System at Equilibrium
Keq =
[C]c[D]d
[A]a[B]b
Once equilibrium is achieved, the amount of each reactant and product remains constant.
N2O4 (g)
2 NO2 (g)

34. Define Le Chatelier’s Principle.
Thursday February 25, 2016
Define Le Chatelier’s Principle.

35. Le Chatelier’s Principle and Stress
REACTIONS AT EQUILIBRIUM WILL SHIFT TO RELIEVE STRESS.
Examples of stress:
Changes in concentration
Changes in pressure (gases only)
Changes in temperature

36. Increase Pressure
A + 2B  C + D

37. N2(g) + 3H2 (g)  2NH3 (g) + heat
Temperature
N2(g) + 3H2 (g)  2NH3 (g) + heat
Increase temperature
Decrease temperature

38. Work Session Le Chatelier’s Principle Chart
Rates of Reactions packet/writing task (due tomorrow!)
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