1. Acids, Bases and pH
Chapter 9
Section 1

2. D12
Explain the chemical composition of acids and bases, and explain the change of pH in neutralization reactions.

3. Learning Target
I can differentiate between acids and bases.

4. Acids When dissolved in water, they ionize (form ions)
Form H+ (Hydrogen) ions, which attach to water molecules to form hydronium ions, H3O+
Properties:
Taste sour
Blue litmus paper turns red
Are able to conduct electric current
Corrosive

5. Strong and Weak Acids

6. Strong Acids HNO3 + H2O H3O+ + NO3- Reactants
Chemical Equation
HNO3 + H2O H3O NO3-
Reactants
Products
Complete ionization in water
High concentration of hydronium ions in the liquid
Strong acid
Strong electrolyte
Conducts electricity
Electrolyte: substance that conducts electricity when dissolved in water

7. Weak Acids CH3COOH + H2O H3O+ + CH3COO- Weak acids
Does not completely ionize
Low concentration of hydronium ions in the liquid
Weak electrolyte
Does not conduct electricity well
Double headed arrow
Few ions in a solution of acetic acid

8. Acid Safety Corrosive Can damage living tissues
Vapors can be harmful to eyes, mouth and lungs
Wear safety goggles, gloves, lab apron

9. Bases When dissolved in water form OH- (hydroxide ions) Properties
Tastes bitter
Solution feels slippery
Turn red litmus paper blue
Are able to conduct electric current
Like acids, bases can also damage the skin

10. Strong and Weak Bases

11. Bases When bases dissolve in water, they ionize. NaOH Na+ + OH-
Not all bases contain OH-
Some will react with water to form hydroxide ion
NH H2O NH OH-

12. Strong Bases High concentration of OH- in the solution
Ba(OH) Ba OH-
Complete ionization in water
Strong electrolyte
Good conductor of electricity

13. Weak Bases Low concentration of OH- in solution NH3 + H2O NH4+ + OH-
Does not ionize completely
Weak electrolyte
Not a good conductor of electricity

14. Base Safety Bases are corrosive and can damage living tissue
Wear safety goggles, gloves and a lab apron!!

15. Let’s Review What ions do acids produce? What ions do bases produce?
What is the difference between a strong acid and a weak acid?
What is the difference between a strong base and a weak base?
Why should we observe lab safety rules when working with acids and bases?
Learning Target Checkpoint
How do you differentiate between acids and bases?

16. Learning Target
I can explain pH.

17. Detecting Acids and Bases
You can determine if a substance is an acid or a base by using an indicator.
An indicator is a substance that changes color in the presence of an acid or base.
Indicators measure the level of hydronium ions. The level determines if a substance is acidic or basic.

18. Indicators Cabbage juice can be used as an indicator
Litmus paper is a common indicator
Acids turn blue litmus paper red
Bases turn red litmus paper blue
Only indicates if a substance is an acid or a base
To determine strength or weakness, pH values are used
catalog.flatworldknowledge.com
profmarsolais.com

19. pH A measure of the concentration of H3O+ ions in solution
Acidity or basicity of a solution can be critical
Enzymes in your body will not function properly if your blood is too basic or acidic
Fish cannot survive in waters that are too acidic or basic
ck12.org
hapnotes.wikidot.com

21. pH Small differences in pH mean large differences in acidity Example:
pH of coke = 3
pH of coffee = 5
Coke is 102 , or 100, times more acidic than coffee.
ch302.cm.utexas.edu

22. gizmodo.com

23. Let’s Review
Lemon juice has a pH of 2.2. Is it an acid or a base?

24. Detergents such as Tide have a pH of about 10
Detergents such as Tide have a pH of about 10. Is Tide an acid or a base?

25. Seawater has a pH of 8.2. Is seawater an acid or a base?

26. The inside of your mouth has a pH of 7. Is it an acid or a base?

27. 409 cleaner contains ammonia that has a pH of 12
409 cleaner contains ammonia that has a pH of 12. What will 409 do to red litmus paper?

28. A soft drink has a pH of 3.2. What will it do to a piece of red litmus paper?

29. Learning Target Checkpoint
What is pH?
How do you determine the pH of a substance?