1. Chemistry Jacqueline P. Hancock, B.S., M.Ed
Acids, Bases, & Salts
Chemistry
Jacqueline P. Hancock, B.S., M.Ed

2. What is expected of me today?
Lecture
Practice Problems
Progress Reports

3. Acid-Base Theories Type Acid Base Arrhenius H+ producer OH- producer
BrØnsted-Lowry
H+ donor
H+ acceptor
Lewis
Electron-pair acceptor
Electron-pair donor

4. Properties of Acids & Bases
Sour taste
Turn blue litmus RED
React with metals to produce hydrogen gas
React with carbonates to produce carbon dioxide
Bases
Bitter taste
Turn red litmus Blue
Slippery to touch
Do not react with metals or carbonates

5. Self- Ionization of Water (Dissociation)
H2O
Highly polar
Constant motion
Pure water contains small concentration of H+ & OH- as well as H2O molec
High energy collisions allows transfer of H+ ions from one H2O to another
Self-ionization-reaction of like molecules to produce ions

6. @ 25oC Equilibrium [H+] is 1x10-7 M Equilibrium [OH-] is 1x10-7 M
Therefore the ion concentrations in pure water are equal making it Neutral

7. Ion-Product Constant

8. Acid or Base?
To determine whether a solution is acidic or alkaline(basic)
Use the exponent value for the ion given
If the H+ is greater than -7 it is..
If the H+ is less than -7 it is…
If the H+ is equal to -7 it is…

9. Practice Problems Classify as acidic, basic, or neutral
[H+]= 6x10-12 M
[OH-] = 3.0x10-2 M
[H+] = 2.0x10-7 M
[OH-]= 1.0x10-7 M

10. Ion Concentration
To determine the ion concentration use the Ion-product constant for water
Rearrange the formula to isolate the unknown variable (solve for the missing variable)
Plug in the known values
Ion-Product Constant Formula g

11. Practice Problems
If the [H+] in a solution is 1.0x10-5M, what is the [OH-] of this solution?
If the hydroxide-ion concentration of an aqueous solution is 1x10-3M, what is the [H+] in the solution? Is the solution acidic, basic, or neutral?

12. pH
1909 Danish scientist SØren SØrensen developed pH scale of (acid to base)
pH is the negative logarithm of the hydrogen-ion concentration of a solution
pH= -log[H+]
pOH= -log[OH-]
pH + pOH = 14

13. Acid pH < 7.0 [H+] > 1x10-7M
Neutral pH= [H+] = 1x10-7M
Basic pH> [H+] < 1x10-7M

14. pH

15. Calculating pH Calculation pH from [H+] pH= -log[H+]
2nd -log[H+]
Find the pH of each solution
[H+] =1x10-4M
[H+] = M
What are the pH values of the following solutions, based on their hydrogen-ion concentrations?
[H+] = 1x10-12M
[H+]= 0.045M

16. Calculating pH Calculating [H+] from pH First rearrange equation
Use pH = -log[H+]
First rearrange equation
-log[H+] = pH
Change signs
log[H+] = -pH
Find anti-log of value
2nd log(-pH value)
Make sure in Sci mode
Calculating pH from [OH-]
Use Kw formula
Use pH= -log[H+]
First find [H+]
Second find –log[H+]
-log(H+ value)
Answer should be positive!!!

17. Practice Problems Calculate [H+] for each solution pH= 5.0 pH= 12.83
Calculate the pH of the solution
[OH-]= 4.3x10-5M
[OH-]= 4.5x10-11M
[H+] = 5.0x10-5M
[H+]= 8.3x10-10M

18. Acid-Base Indicators Know Figure 19.2
An indicator(Hln) undergoes dissociation in a known pH range
Changes colors in different solutions
Limits of liquid indicators
Optimal temp 250C
Color sol. Can distort
Dissolved salts can affect dissociation
Paper indicators
pH meters
Know Figure 19.2
Thymol Blue
Bromphenol Blue
Bromcresol green
Methyl Red
Alizarin
Bromthymol Blue
Phenol Red
Phenolphtalein
Alizarin yellow R