1. 15.2 NOTES Acid Rain and Concentration

2. 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

4. Rain is normally acidic due to the reaction of carbon dioxide with water forming carbonic acid, H2CO3
This reaction is:
H2 + CO2  H2CO3
There are several naturally occurring reasons for acid rain, including
Volcanoes, forest fires, lightning
Various other gases such as SO2, SO3, and NO2 react in similar ways to CO2

6. 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

7. Impact of Acid Rain
Power plants, industry, and vehicles produce CO2 that lowers pH of rain
Can kill fish eggs and other aquatic life
Can remove minerals from the soil

8. 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, CaCO3)
H2SO4 + CaCO3  CaSO4 + H2O + CO2
CaSO4 is much more soluble than CaCO3

9. 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

10. Clean Air Act Amendments of 1990
Addresses acid rain
Allow maximum amount of SO2 released by plants
Use lower sulfur coal
Scrubbers on smokestacks, but is more expensive than coal, currently

12. 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 engines
SO2 emissions are lower, but NOx aren’t as low

13. 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

14. C.6 Acidity, Molar Concentration, and pH
Solutions
Made from two parts, the solute and the solvent
The solute is dissolved by the solvent

15. Molar Concentration
Also called molarity (M)
M = moles of solute
Liters of solution

16. What is the molarity of a solution made from dissolving 3
What is the molarity of a solution made from dissolving 3.4 moles of NaCl in 1.7 L of water?

17. The equations for this is M1V1 = M2V2
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 M1V1 = M2V2

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