Lecture Acids and Bases

How did you get to school today?

Do you drink sodas/how often?

Do you use a cell phone, computer, flashlight, ipod?

Do you think its ok to take medicine?

What do all these questions have to do with acids and bases?

How do acids and bases relate to the use of a coin?

1. Introduction: Acids and bases are a characteristic propertyA. define and draw

1. water2. proton3. ion4. H+

5. acid6. pH

B. what part of your body is acidic?C. what do you put on your body which is a base?D. what do you eat which is an acid?

2. Acids

A. made of substances which have loose or free hydrogen ions: H+ (also known as protons: lacks the electron), thus

act as proton donators to other substances

H30+ is what water becomes w/ extra H+ (hydronium)

B. have a pH of <7 (coin?)

C. sour taste in your mouth: ?

D. turns litmus paper from blue to red

E. reacts with metals to produce hydrogen gas: Mg and HCl lab?

F. food acids: vinegar (acidic acid), citric acid (?), sodas (CO2 reacts with the water to make carbonic acid: H2CO3)

G. common science acids: HCl (hydrochloric acid, stomach acid!), H2SO4 (sulfuric acid: car batteries)

H. strong acids

1. easily release their H+

2. conduct electricity very well: e- flow

3. measured by concentration of H+: called molarity

4. HCl is strong, vinegar is not

3. Bases

A. made of substances which easily release hydroxide ions: OH-

B. act as proton acceptors

C. have a pH >7 (coin?)

D. have a bitter taste in the mouth and a soapy feel:?

E. turn red litmus paper blue

F. household bases: milk, soap, deodorants, ammonia, bleach, baking soda

G. science bases: sodium hydroxide (NaOH)

H. dissolves fats/oils to produce soap:?

4. Indicators: substances used to determine both the type of chemical (acid, base neutral) and sometimes its strength

A. litmus paper: blue and red (strength?)

B. bromothymal blue: blow into water with it: tells carbonic acid created and how strong by the color change intensity: blue to yellow

C. phenolthalyine

D. congo red

E. pH paper

E. pH (parts of hydrogen) (coin?)

1. measures the (inverse log) amount of H+ (thus also the relationship to amount of

OH-)

2. range of 014

3. <7 = acid (lots of H+, little OH-)

4. >7 = base (lots of OH-, little H+)

5. =7 = neutral (equal H+ and OH-)

6. difference between each pH is a measure of 10 times in strength!:

pH 8 to 11 is 10x10x10= 1,000 times stronger

Lye

Stomach acid

Pure water: H2O

Lemon juice

Acid rain

blood

soap

bleach

14

0

7

5.6

1

2

7.4

10

13

OH-

H+

H2O

Base

Acid

Neutral

pH:

5. Salts

A. acids and bases combined form salt

B. a second product is often a metal

C. when they neutralize each other the product is water

NaOH + HCl H2O + NaCl

D. salts are corrosive(?), but acids and bases are even more corrosive

6. Blood

A. is filled with CO2 from cellular respiration: it’s what you breathe out

B. this forms carbonic acid in the blood (sodas?)

C. but, the body buffers this by adding baking soda to the blood, making blood basic (7.4 pH)

What is this all about?

7. Acid rain

A. pH < 5.6 (rain is acid already from dissolving atmospheric CO2, but it’s not this acidic)

B. burning fossil fuels are the primary cause

1. transportation and industry two main sources (human induced!!!)

2. produce sulfur and nitrogen oxides

3. these combine with atmospheric water to form sulfuric acid and nitric acid rains.

4. produced around big cities, but travels in the air: global issue.

5. some regions are dead: void of life, esp. some lakes in NE USA and eastern

Europe

8. Sink

A. atmosphere has CO2 build-up

B. rain falling through it produces carbonic acid (not acid rain: not a strong acid)

C. oceans act as an acid absorber: sink

D. oceans can counteract the carbonic acid input for only so long, then what?