15.2 NOTES Acid Rain and Concentration - PowerPoint Presentation

Slide1

15.2 NOTESAcid Rain and Concentration

Acid rain along with increased

carbon dioxide levels are a problem from

burning

fuel

C.1

Acid Rain

Acid rain

Any type of precipitation that is acidic

Fog

,

sleet

,

snow

, or

rain

with a pH lower than

5.6

, which is the average pH of natural precipitation in the absence of air pollution

Rain is normally acidic due to the reaction of carbon dioxide with water forming

carbonic

acid, H

2

CO

3This reaction is:H2 + CO

2



H

2

CO

3

There are several naturally occurring reasons for acid rain, including

Volcanoes

, forest fires, lightning

Various other gases such as

SO

2

, SO

3

, and

NO

2

react in similar ways to CO

2

The acidity of rain varies across the country

Higher acid content is found farther

east

, closer to

manufacturing

 Can be as low as pH of 4.5 or less 

Impact of Acid RainPower plants, industry, and

vehicles

produce CO

2

that lowers pH of rain

 Can kill fish eggs and other aquatic life Can remove

minerals from the soil 

Deterioration of buildings and monuments

Buildings contain metal,

limestone

, or concrete that are all affected by acid rain

Ancient monuments have damage due to recent industrial action reacting with the limestone (calcium carbonate, CaCO

3)H

2SO4 + CaCO

3



CaSO

4

+ H

2

O + CO2 CaSO4 is much more soluble than CaCO3

Addressing Acid Rain

It is very difficult to control acid rain because rain moves with weather patterns from

west

to

east

You can’t prevent weather from moving

Clean Air Act Amendments of 1990

Addresses acid rain

Allow maximum amount of

SO

2 released by plants Use lower sulfur

coal Scrubbers on smokestacks, but is more expensive than coal, currently

Nitrogen

oxides

cause almost as many problems as carbon products released in to the atmosphere

Nitrogen oxides are formed by reactions with atmospheric nitrogen with oxygen at high temps, ie combustion

enginesSO2 emissions are lower, but NOx aren’t as low 

ChemQuandry

Why is Maine’s precipitation pH so acidic when it has very little in the way of coal power plants and few residents per square mile?

Farthest east in the US and weather can dump all of its acid there

C.6 Acidity, Molar Concentration, and pH

Solutions

Made from two parts, the solute and the solvent

The

solute

is dissolved by the solvent

Molar Concentration

Also called

molarity

(M)

M = moles of solute Liters

of solution

What is the molarity of a solution made from dissolving 3.4 moles of

NaCl

in 1.7 L of water?

Can use different quantities to reach same concentration. Acids are typically sold in solutions with very

high

molarities, and can be diluted down to a

lower

molarity by adding water.

 The equations for this is M1V

1 = M2V2

How much concentrated 12 M carbonic acid is needed to make .25 L of acid with a concentration of 5.5 M?