Acids and Bases

OAcids are compounds that add

(H+) ions to water when in a solution.

  In Water

OHCl: a very strong acid. In water it breaks up (dissociates) and adds H+ to the water.

Acids

H+

Cl- Cl-

H+

O Bases are compounds that add (OH-) ions

to water when in a solution.

In water

 

ONaOH: a very strong base. In water it breaks up (dissociates) and adds OH- to the water.

Bases

H+

O2-

Na+

H+

O2-

Na+

O Many foods are acidic: Tomatoes

Lemons

Oranges

Limes

Apples

vinegar

O Acids taste sour and feel

squeaky when you rub them between your fingers

Common Acids

O Many cleaners are basic:

Soap

Bleach

ammonia (Windex) 

O Bases taste bitter

and feel slippery when you rub them between your fingers

 

Common Bases

Question #1

O Are antacids acids or bases?

O Why?

SafetyO Acids are corrosive! They

can burn your skin or eyes.O Bases are caustic! They

can burn your skin or eyes. 

O Why do you think the safety sign for acids and bases is the same sign?

Other TermsO Strong acids and

bases—ionize (dissolve) completely in water, adding many ions to the water

 O Weak acids and

bases—do not ionize (dissolve) completely in water, adding fewer ions to the water.

 

The pH Scale

Litmus PaperO Acids are

indicated by a Red color.

O If Red litmus paper is dipped in an acid it will stay Red

O If Blue litmus paper is dipped in an acid it will turn Red

Litmus PaperO Bases are

indicated by a Blue color.

O If Blue litmus paper is dipped in a base it will stay blue

O If Red litmus paper is dipped in a base it will turn Blue

Question #2!O What is the difference between the pH scale

and litmus paper?

O Neutralization Reaction: When acids and bases are mixed together, they neutralize each other. If an equal concentration of acid and base are mixed, they make a neutral solution of a salt and water

 

HCl + NaOH —> H2O + NaCl

Acid Base Water Salt 

Acid-Base Reactions:

Neutralization

H+

O2-

H+

H+

H+O2-

Titration (Lab Process)OThe lab process where this is studied is called titration and it uses a piece of glassware called a buret.

Acid RainO Acid Rain: Plants and animals

need water close to neutral (pH 7) to survive.

O Due to pollution from industries and cars, rain in certain areas can be acidic. Rain less than pH 5.6 is called acid rain.

O Acid rain can kill plants, cause asthma, and other physical problems.

O Because statues and landmarks are made of limestone (a base), acid rain will also slowly destroy them.  

Acid Rain (cont)O The Roman ruins, the

pyramids of Egypt, and other treasures of the world are slowly being reacted away by acid rain.

O More damage has been done in the last century than in the last 2,000 years.

Acid Rain (cont)O Why do you think there has

been more damage from acid rain in the last 100 years?

Let’s See What You Know…Letter Matching

1. Acid A. To mix acids and bases to cancel each other out and make water and salt

2. Base B. A compound that adds H+ ions to water

3. Neutral C. Equal number of H+ and OH- ions; water is an example

4. Neutralize D. A compound that adds OH- ions to water.

5. Acid Rain E. When pollution causes rain to have a pH less than 5.6.

6. pH F. The measure of how acidic or basic a solution is

7. Salt Water G. A compound that adds a few OH- ions to water

8. Strong Acid H. The product of a neutralization reaction between an acid and a base

9. Weak Base I. A compound that adds a few H+ ions to water

10. Weak Acid J. A compound that adds a lot of H+ ions to water.

A

B

D

E

F

H

J

G

I

C

Part II….Is it an Acid or a Base?

Circle the acids and underline the bases 11. HCl

17. H2CO3

23. apple juice

12. Mg(OH)2

18. NaOH

24. lemonade

13. H3PO4

19. Al(OH)3

25. soap

14. KOH

20. HBr

26. laundry detergent

15. Ca(OH)2

21. H2SO4

27. soft drinks

16. LiOH

22. H2O

28. bathroom cleaner

Part IIIAcids or Bases? Identify the

following with an A for Acid or B for Base

29. pH of 1 to 7

30. Feels slippery

31. pH of 7 to 14

32. Has more OH- ions

33. Has more H+ ions

34. Tastes sour

A

B

B

B

A

A

TAKS Practice1 A student wearing goggles, gloves, and an apron begins a simple activity to determine the pH of corrosive solutions. Before the activity, what other safety measures should the student follow?

A Identify the locations of eye wash, shower, and fire equipment B Check and set clocks and record the beginning time C Review the proper method of fire-polishing glass tubing D Arrange the equipment in the work area alphabetically

TAKS Practice2 Hard water has a pH higher than 7 and an abundance of calcium and magnesium salts. Which of the following would be the best cleaning solution for removing hard-water residue from drinking glasses?

A A mild acid such as vinegar B A strong solution such as ammonia C A hot solution such as baking soda in boiling water D A strong base such as sodium hydroxide

TAKS Practice 3 Two clear solutions are placed in separate beakers. The first solution has a pH of 4, and the pH of the second solution is unknown. If the two solutions are mixed and the resulting pH is 5, the second solution must have –

A fewer suspended solids B a lower temperature C more dissolved salt (NaCl) particles D a higher concentration of OH-ions

TAKS PracticeProperties of Some Solutions

Solution Electrical

Conductivity of Solution

Original Color of Litmus Paper

Color of Litmus Paper After Dipping in Solution

pH

1 Very high Red Blue 10.0 2 Low Blue Red 6.5 3 Moderate Red Red 5.4 4 Very high Blue Red 2.0

4 The table shows data from an investigation designed to find a liquid solution that is both an acid and a strong electrolyte. Based on the data, a solution that is both an acid and a strong electrolyte is –

A Solution 1 B Solution 2 C Solution 3 D Solution 4

Venn Diagram of Acids and Bases

O At least 3 points about Acids and Bases

O At least 2 points about what they have in common