1. Introduction to ACIDS and BASES

2. What are Acids and Bases?
Warm Up
Title your CB-
What are Acids and Bases?
Write everything you know about the properties of acids and bases.
Why are they important?

3. Acids and Bases are part of your everyday lives!
Acids Bases

4. Definition
An acid is a compound that produces hydrogen ions (H+) when dissolved in water.
A base is a compound that produces hydroxide ions (OH-) when dissolved in water.

5. Properties of Acids and Bases
Sour taste
Neutralize bases
Release hydrogen gas when added to an active metal
Aqueous solutions of acids are electrolytes (conduct electricity)
Bases
Bitter taste
Feels slippery
Neutralize acids
Aqueous solutions of bases are electrolytes (conduct electricity)

6. What do you think?
1. Based on the properties of the following, predict if the product is an acid or base.
Shampoo
Lemonade
Windex
Gatorade
2. Do you think Draino is an acid or a base? Why?

7. Warm Up
Things I am collecting: Article Analysis Chapt 12.1 Notes Molarity Packet Review
Things I have already collected: KNO3 Lab Solubility Rule Lab Solubility Curve WS (not the one with water)

8. What is happening in the tube?
Rainbow Tube Demo
What is happening in the tube?

9. WATER
Water molecules are highly polar and are in continuous motion when at room temperature. When collisions between water molecules occur, a hydrogen ion can transfer from one water molecule to another. This is called the self-ionization of water.

10. Self Ionization of Water
Water molecules collide with one another to cause the self-ionization reaction represented by this equation:
2H2O H3O+ + OH-
It is a reversible reaction so the equation is usually written with the arrows going in both directions:
2H2O H3O+ + OH-

11. Self Ionization of Water
In pure water the H+ and OH- are produced in a 1:1 ratio.
[H+] = [OH-]
A neutral solution is when [H+] = [OH-]
Water is a Neutral Solution!

12. Self Ionization of Water
In any aqueous solution [H+] and [OH-] are interdependent.
[H+] increases then [OH-] decreases.
[H+] decreases then [OH-] increases.
This is an example of Le Chatelier’s Principle.

13. Le Chatelier’s Principle
Equilibrium
H2O H+ + OH-
If a stress is applied to a system in a dynamic equilibrium, the system changes to relieve the stress.

14. Le Chatelier’s Principle
If we add more reactants the system looks like this:
However, the system will correct itself and make more products to balance the system.

15. Le Chatelier’s Principle
Similarly, if we add more products to the system, it will look like this:
But a system that is in equilibrium will shift again to relieve stress:

16. Where X are the coefficients in the
Equilibrium Constant
For every reaction there is a mathematical relationship between the reactants and products.
Keq = [Products]x
[Reactants]x
Where X are the coefficients in the
balanced equation.

17. Example Write the equilibrium constant for the following reaction.
H2SO4 + 2NaOH Na2SO4 + 2HOH

18. 4/19 Warm Up- Look through Acid/Base Notes!
What are the properties of acids?
What are properties of bases?
We know that there was some crazy equilibrium crap (did I just say that?)…
We also know that there is a relationship between [H+] and [OH-] ions.
Last-- we know that there is a pH scale.
Hmmmmmm……. How does it all fit together?

19. Lets start with the pH scale
pH is a logarithmic function based on the [H+]

20. KW = [H+] [OH-] = 1.0 X 10-14 (mol/L)2
The first step in pulling it all together is knowing the Ion-Product Constant for Water KW
The product of the concentrations of the hydrogen ions and hydroxide ions in water is KW and equals 1.0 X (mol/L)2
KW = [H+] [OH-] = 1.0 X (mol/L)2
[H+] = 1.0 X 10-7 mol/L [OH-] = 1.0 X 10-7 mol/L

21. Knowing Kw and the concentration of one of the variables, we can determine the other!
Go to the WS

22. Calculating pH
Keeping in mind that pH is a logarithmic function, we can calculate the pH using the following equation.
pH = -log [H+]

23. Try these! Determine the pH. Get your calculators out!!
[H+]= 1.0 x 10-7
[H+]= 1.0 x 10-5
[H+]= 1.0 x 10-9
[H+]= 2.5 x 10-9
[H+]= 1.6 x 10-5
[H+]= 3.7 x 10-9

24. How did you do?
[H+]= 1.0 x pH= 7
[H+]= 1.0 x pH= 5
[H+]= 1.0 x pH= 9
[H+]= 2.5 x pH= 8.6
[H+]= 1.6 x pH= 4.8
[H+]= 3.7 x pH= 8.4

25. What is pOH pOH is a logarithmic function of the [OH-].
It works exactly the same as pH.
pOH = -log[OH-]

26. What is the relationship between pH and pOH??
pH + pOH = 14
Yea!

27. Calculations Columns 7-8 are the calculations we learned on Friday.
Columns 9 and 10- Concentration is in mol/L. Calculate how many moles in 2L of solution.

29. Adding Acid to Water HCl  H+ (aq) + Cl- (aq)
The acid adds more H+ increasing the [H+] in the water. Therefore in any acid solution the [H+] will be greater than the [OH-].
[H+] > 1.0 X mol/L
[H+] > mol/L

30. NaOH  Na+ (aq) + OH- (aq)
Adding Base to Water
NaOH  Na+ (aq) + OH- (aq)
The base adds more OH- increasing the [OH-] in the water. Therefore in any basic solution the [OH-] will be greater than the [H+].
[H+] < 1.0 X mol/L
[H+] < mol/L

31. pH Scale
The pH of a solution is the negative logarithm of the hydrogen-ion concentration.
pH = -log [H+]
Neutral pH = 7 [H+] = 1.0 X mol/L
Acidic pH < 7 [H+] > 1.0 X mol/L
Basic pH > 7 [H+] < 1.0 X mol/L

32. pH Scale
Explain that pH scale is an exponential model.

34. Indicator
A substance that “indicates” the pH of a solution by changing color. Red Litmus Paper Blue Litmus Paper Universal Indicator Paper Red Cabbage Juice

35. Household pH Lab
You will be testing the pH of many solutions that you use every day.
1. What do you think?
2. Cabbage Juice- 10 mL juice, add a few drops of sample.
2. Litmus Paper– Use blue and red!
(example: Red turns Blue)
3. Universal pH paper- record color and approximate pH.
4. Actual pH- from meter (I will give you these).

36. Arrhenius Definition
An acid is a compound that produces hydrogen ions (H+) when dissolved in water.
A base is a compound that produces hydroxide ions (OH-) when dissolved in water.