1. REVIEW QUIZ What does UBIQUITOUS mean?
How does High Specific Heat relate to your swimming pool?
What is surface tension?
Draw the water molecule , add the charges.
What is adhesion, cohesion and how do they relate to capillary action?
What does UNIVERSAL SOLVENT mean?

2. Directions: Take notes Do Lab Review
pH Notes
Directions:
Take notes
Do Lab
Review

3. pH PRE Quiz What does pH stand for? What is neutral on the scale?
What liquid represents neutral?
What is the highest rating on the scale?
Is the highest rating an acid or base?
What is the lowest rating?
Is the lowest rating an acid or base?

5. pH Defined pH stands for “potential for Hydrogen”
pH is defined as the negative logarithm of the hydrogen ion concentration:
pH = - log [H+]
pH stands for “potential for Hydrogen”

6. What is pH? The pH scale measures how acidic or basic a substance is.
The pH scale ranges from 0 to 14.
A pH less than 7 is acidic.
A pH of 7 is neutral.
A pH greater than 7 is basic.

7. ? Logarithms ?
Logarithms of numbers that are multiples of ten are merely the exponents of the number including the sign.
NUMBER
EXPONENT
LOG
1000
10³ 3
100
10² 2 10
10¹ 1
10⁰
0.1
10-¹ -1
 0.01
 10-2
 -2
 0.001
 10-3
 -3

8. Soo…
The pH scale is logarithmic and as a result, each whole pH value ten times more or less concentrated.
For example, pH 4 is ten times more acidic than pH 5 and 100 times (10 times 10) more acidic than pH 6.
For example, pH 10 is ten times more alkaline than pH 9 and 100 times (10 times 10) more alkaline than pH 8.

10. How it works
In pure water (H2O), there are an equal number of hydrogen ions (H) and hydroxyl ions (OH). The solution is neither acidic or basic.

11. Dissociation
It all has to do with hydrogen ions (H+). In water (H2O), a small number of the molecules dissociate (split up).

12. Some of the water molecules lose a hydrogen and become hydroxyl ions (OH−) or bases.
The "lost" hydrogen ions join up with water molecules to form hydronium ions (H3O+) or acids.

13. So as the H+ conc. ↑ the OH- ↓ and visa versa

14. RCC Draw and label a HYDRONIUM molecule.
Draw and label HYDROXIDE molecule.
Why is water neutral?
What does dissociate mean?
If you add acid to a pH 3 does the pH increase or decrease?
If you add acid to a pH 10 does the pH increase or decrease?
If you remove base from a pH 9 does the pH increase or decrease?
If you remove acid from a pH 6 does the pH increase or decrease?

15. Household items
pH is measured with a pH meter or with Litmus paper – which you used in your lab.

16. Properties of Acids (H+)
Sour taste (do not taste!)
Change indicator to red
React with active metals to form hydrogen gas and a metal compound
contains hydrogen
Proton donors

17. Properties of Bases (OH-)
bitter taste (Do not taste!)
slippery to the touch (DO not Touch!)
change indicator to blue
Emulsify (combine) fats and oils (thereby making them useful cleaning agents)
contain the OH- ion
proton acceptors.

18. When acids and bases mix…
A salt is any compound which can be derived from the neutralization of an acid and a base.
The word "neutralization" is used because the acid and base properties of H+ and OH- are destroyed or neutralized.
In the reaction, H+ and OH- combine to form HOH or H2O or water molecules.
See demo
(A salt and water are produced)

19. Danger!
Acids and bases are examples of corrosive poisons which react locally on tissue cells.
Chemicals that are very basic or very acidic are reactive.
These chemicals can cause severe burns, causing ultimate disintegration of the tissue.
The eyes and lungs are particularly sensitive to corrosive poisons.

20. Life Biological systems operate within a narrow pH
range and can be negatively impacted by a change of pH.
- Blood
- Salt water fish 8.0 and higher
- Fresh water fish 5.5 – 7.5
- Swimming pool

21. Conclusion…pH is good to know
pH AND YOU – REVIEW
CRASH COURSE
Get HW sheet
DO HW sheet
Tomorrow we will CHECK HW sheet
Monday we will have an assessment