1. pH

2. How do acids and bases work?
In solution, acids RELEASE hydrogen ions
In solution, bases RECEIVE hydrogen ions

3. Acids… H+ React with metals Watery They burn!!!
HCl, H2NO3, H2SO4, HNO3

4. Bases…
OH-
Does not react with metals
Slimy
Burn!!!
NaOH
KOH

5. What happens if I mix a strong acid with a strong base?
Let’s mix HCl with NaOH….

6. What is pH? What does that mean?
0-14 scale used to specify acidity or alkalinity of an aqueous solution
Measure of the STRENGTH of the acid or base character of a substance
Mathematical definition? pH = -log[H+] Sometimes written as
pH= log [H3O+]

7. pH Calculation
Concentrations are small numbers! It’s only a measure of the concentration of hydrogen ions, and those are small
Ex: Let’s figure out the pH of a solution with the H+ concentration 1x10-3
What is that in standard form? 0.001
All you do is take the negative log of that number… -log(1x10-3) and you get a pH of 3!

8. Types of Acids and Bases
Strong Acids (about 0-2) battery acid, stomach acid, vinegar
Weak Acids (about 4-6) tea, coffee, sweat
Neutral Stuff (around 6-8) pure water, urine, saliva, blood, milk, tears
Weak Bases (about 8-10) sea water, baking soda, eggs, deodorant
Strong Bases (about 12-14) bleach, detergents, drain cleaner

9. Strong Acids vs Weak Acids
Strong acids ionize strongly and completely and release a lot of protons!
Weak acids disassociate incompletely and release a smaller amount of hydrogen ions

10. Strong Bases vs Weak Bases
Strong bases consume large amount of hydrogen ions, leaving the concentration low. Large pHs!
Weak bases do not consume as much hydrogen ions like their strong counterparts, so there will be more hydrogen ions left. Not as large pHs!

11. Flip Side! Yes, there’s a pOH –log[OH-]
How do you get it? Subtract the pH from 14!
pH + pOH = 14 ALWAYS, or 1.0x10-14 mol/L = [H+][OH-]
So, if the pH is 3.5, what’s the pOH?

12. YouTube Overview