1. Identification and Properties
Acids and Bases
Identification and Properties

2. Acids

3. Acids – Arrhenius Definition
Produce Hydronium ion (H3O+1) in water
Hydronium ion is H2O + a hydrogen cation H O
water H O +1 H +1
Hydrogen ion
Hydronium Ion
Acids give a H+1 to water. All acids have hydrogen as the cation!
(Review – Cation is always listed first!)

4. How do Acids produce Hydronium?-
water
acid
Hydrogen cation with some anion

5. How do Acids produce Hydronium?- +1 H O

6. How do Acids produce Hydronium?- +1 H O
Hydronium ion
Anion

7. Bases

8. Bases – Arrhenius Definition
Bases produce the hydroxide ion in water H O -1
Hydroxide Ion

9. Characteristics of Acids and Bases
Now that we know what acids and bases are, how do they act?

10. Characteristics of Acids & Bases
Produce H3O+1 (hydronium ion) in water
Produce OH-1 (hydroxide ion) in water
Tastes sour
Tastes Bitter
React with active metals to form hydrogen gas
Feels slippery

11. Strength versus Concentration

12. Review of how acids produce ions-
water
acid
Hydrogen cation with some anion

13. Review of how acids produce ions- +1 H O

14. Review of how acids produce ions- +1 H O
Hydronium ion
Anion

15. Strong versus Weak Acids
How many hydronium ion – anion pairs can you find? - + - 3 +
How many intact acid molecules can you find? + -
Strong acids
Completely Break apart (Dissociate)
All of the acid molecules have donated their H+1 to water

16. Strong versus Weak Acids+
How many hydronium ion – anion pairs can you find? 1
How many intact acid molecules can you find? - 3
Weak acid -
Only a few of the acid molecules have donated the H+1 to water

17. Concentrated versus Dilute
solvent
solute
Lower concentration
Not as many solute (what’s being dissolved) particles
Higher concentration
More solute (what’s being dissolved) particles

18. Combinations of Concentration & Strength
Concentrated
Dilute
Strong
A lot of acid added & all dissociates
Not much acid added, but all dissociates
Weak
A lot of acid added, but most stays together
Not much acid added and most stays together

19. Other notes
All of the same ideas apply to bases as well (concentration and strength)
Acids and Bases can be very helpful or harmful. It depends on concentration!
Vinegar is an acid we eat…It is safe because it is dilute.

20. pH

21. pH Scale pH is a scale to measure the acidity of a sample 1 14 7
Highly acidic
Very basic (not acidic)
neutral 7
Chapter 6 will give more detail about how pH is calculated!

22. Ways to measure pH Indicators change color based on pH
Liquid indicators
Universal indicator – a combination of liquid indicators to produce a “rainbow” changing colors at several pH’s
Paper Indicators
Paper with a liquid indicator on it (Litmus paper or pH paper)
pH meters or pH probes
Electronically determine pH and give a read-out

23. Common pH indicators
This picture © 1998 David Dice

24. pH of common substances
0.1M HCl 1
Stomach contents 2
Vinegar
2.9
Soda pop 3
Grapes 4
Beer
4.5
Pumpkin pulp 5
Bread
5.5
Intestinal contents
6.5
Milk
Urine
6.6
Bile
6.9
Saliva 7
Blood
7.4
Eggs
7.8
0.1M NH3 (aq)
11.1
0.1M NaOH 13