1. Chemistry – May 13, 2019 P3 Challenge – H2SO4 + 2 OH-  2 H2O + SO42-
A) Identify acid, base, conjugate acid, conjugate base
B) Draw a bracket line connecting conjugate acid- base pairs
Get out Acid Base WS pg 1 for HMW check

2. Chemistry – May 13, 2017 Today’s Objective – pH Assignment: Agenda
Acid/Base pH Worksheet
Quest on Wednesday
Agenda
Homework Review
Self-ionization of water
pH, pOH
Classwork on pH table
Quest description
Review of pH table

3. Water Because water is amphoteric: can act as an acid or a base.
Water can react with itself, acting as both the acid and base:
H2O(l) + H2O(l)  H3O+ (aq) + OH- (aq)
This reaction is the self-ionization of water, and happens in very small amounts.
In pure water at 25◦C, [H+] = [OH-] = 1 x 10-7 M = M
Product of these two concentrations is called the ion product of water Kw = 1 x = [H+] [OH-]
The ion product of water is true for all acidic or basic solutions.
H3O+ = H+

4. Relative concentrations
[H+]
[OH-] Kw
1.E-01
1.E-13
1.E-14
1.E-02
1.E-12
1.E-03
1.E-11
1.E-04
1.E-10
1.E-05
1.E-09
1.E-06
1.E-08
1.E-07

5. pH pH = -log [H+] [H+] Opp of Exp pH 1.E-01 1 1.E-02 2 1.E-03 3 1.E-045
1.E-06 6
1.E-07 7
1.E-08 8
1.E-09 9
1.E-10 10
1.E-11 11
1.E-12 12
1.E-13 13
Easier to refer to [H+] based on the exponent.
More specifically the opposite of the exponent because they are negative.
We call this value pH.
Small pH values, have highest [H+]
Mathematically,
pH = -log [H+]

6. Acidic, Basic, or Neutral pH
pH is by far the most common way to describe the acidity/basicity of a solution
Always remember that pH is a log function: each increase by 1 is a factor of 10.
Ex: pH = 7 pH = pH = 8.2

7. pOH It is much less common than pH, but you can similarly define pOH
pOH = -log [OH-]
Low pOH values are basic, high pOH values are acidic, 7 is neutral.
pH +pOH = 14
Ex: If pOH = 4, pH =
Ex: If pOH = 10, pH =
Often easiest, to convert pOH to pH when identifying acidity.

8. pH Calculations Four related quantities: pH, pOH, [H+] and [OH-]
pH = -log [H+] , pOH = -log [OH-], Kw = [H+] [OH-] = 1 x , pOH + pH = 14
Note: the opposite of pH = -log [H+] is [H+] = 10 –pH
Calculate the other three quantities for the given information. Then indicate if it is an acidic or basic solution.
[H+] = 4.0 x 10-3 M
[OH-] = 1.5 x 10-5 M
pH = 2.1
pOH = 3.5

9. Quest Description 3 x 4 pts Balance and Write Keq
1 x 8 pts Calculation with Keq
7 x 2 pts Equilibrium L/R shifts
1 x 4 pts A/B/CA/CB equation
12 x 1 pt pH/pOH etc.. table

10. Exit Slip - Homework
Exit Slip: An acidic solution has [H+] = 4.5 x 10-4 M. What are a) the pH b) the pOH and c) [OH-]
What’s Due? (Pending assignments to complete.)
Acid/Base pH worksheet - Show me by end of class
What’s Next? (How to prepare for the next day)
Read p