Acids and Acid Rain

Acids, Bases, Buffers and Acid Rain

VOCABULARY TERMS:IONIZATIONAtoms can gain or lose electrons in order to form ions

DISSOCIATION When ionic compounds dissolve in water, their ions separate from one another Steve Spangler Acids and Bases Youtube

Ionization of Water youtube (29 secs)

H+ will quickly attach to another water moleculeWhat determines if it is becoming an acid or a base?

Dissociation of Water Podcast (2:37) southern accent

reversible

EquilibriumconstantWhat is Kw?Kw is essentially just an equilibrium constant for the reactions shown. You may meet it in two forms:Based on the fully written equilibrium . . .

. . . or on the simplified equilibrium:

FYIA hydrogen ion is also just a proton.

Nice Nerdy ExplanationDissociation of Water (youtube 4:33)

Nice Nerdy Explanation

pH Indicates the acidity [H3O+] of the solution pH = - log [H3O+] From the French pouvoir hydrogene (hydrogen power or power of hydrogen)

LecturePLUS Timberlake18pHIn the expression for [H3O+] 1 x 10-exponent

the exponent = pH [H3O+] = 1 x 10-pH M

LecturePLUS Timberlake19pH Range: each number is 10 times more concentrated H+ than the number above it0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

Neutral[H+]>[OH-] [H+] = [OH-] [OH-]>[H+]

LecturePLUS Timberlake20AcidicBasicSome [H3O+] and pH[H3O+] pH1 x 10-5 M 51 x 10-9 M 9 1 x 10-11 M 11

LecturePLUS Timberlake21pH of Some Common Acidsgastric juice1.0lemon juice2.3vinegar2.8orange juice3.5coffee5.0milk6.6

LecturePLUS Timberlake22

pH of Some Common Basesblood 7.4tears 7.4seawater 8.4milk of magnesia10.6household ammonia11.0

LecturePLUS Timberlake23

Learning CheckA. The [H3O+] of tomato juice is 1 x 10-4 M. What is the pH of the solution?1) - 42)43)8B. The [OH-] of an ammonia solution is 1 x 10-3 M. What is the pH of the solution?1) 32)113)-11

LecturePLUS Timberlake24Learning CheckA. The [H3O+] of tomato juice is 1 x 10-4 M. What is the pH of the solution?1) - 42)43)8B. The [OH-] of an ammonia solution is 1 x 10-3 M. What is the pH of the solution?1) 32)113)-11

LecturePLUS Timberlake25Learning CheckThe pH of a soap is 10. What is the [H3O+] of the soap solution?1) 1 x 10 - 4 M2) 1 x 1010 M3) 1 x 10 - 10 M

LecturePLUS Timberlake26SolutionKw = [H3O+ ][OH-] = 1.0 x 10 14

A. [H3O+] = 1.0 x 10 -14 1.0 x 10-10 [OH- ] = 10-4 or pH 4

LecturePLUS Timberlake27Bufferssolution in which the pH of the solution is "resistant" to small additions of either a strong acid or strong base.

Buffer Animation

Carbonic acid is a good blood bufferBuffer exampls

Where are buffers used?chemical research, biological research industryYour body uses buffers to maintain a blood pH of 7.35-7.45, massive number of biochemical reactions involving enzymes.

Acid RainUnpolluted rain has a pH of 5.6 Rain with a pH below 5.6 is acid rainCO2 in the air forms carbonic acid CO2 + H2O H2CO3 Adds to H+ of rain H2CO3 H+ (aq) + HCO3-(aq)

LecturePLUS Timberlake32Formation of acid rain:1. Emission of sulfur and nitrogen oxides

SO2 26 million tons in 1980NO and NO2 22 million tons in 1980Mt. St Helens (1980) 400,000 tons SO2

Sources of Acid Rain

Power stationsOil refineriesCoal with high S contentCar and truck emissionsBacterial decomposition, and lighting hitting N2LecturePLUS Timberlake34

2. Reactions in the atmosphere form SO32SO2 + O2 2 SO3

3. Reactions with atmosphere water form acidsSO3 + H2O H2SO4 sulfuric acidNO + H2O NO2 nitrous acid HNO2 + H2O HNO3 nitric acid

Effects of Acid RainLeaches Al from soil, which kills fishFish kills in spring from runoff due to accumulation of large amounts of acid in snow Dissolves waxy coatings that protect leaves from bacteriaCorrodes metals, textiles, paper and leather

LecturePLUS Timberlake37Criteria Air Pollutants: NOx and SOx200+ now-fishless lakes in AdirondacksLittle Echo Pond, Franklin, NY pH = 4.2Thousands of lakes in Canada (Ontario, Quebec, New Brunswick) now-fishless

http://www.elmhurst.edu/~chm/vchembook/194acidraineffects.html38measure of the buffering capacity of water, or the capacity of bases to neutralize acids; the ability of water to resist change in pH pH Scale MatchingQuia - The pH ScaleWrite the order you think these are from pH 1-14.

1Stomach Fluids 7Pure Water 11Rolaids, Tums 13Bleach 2Lemon Juice 5Coffee 3Vinegar 8Blood 10Borax 14Lye 4Tomatoes 6Milk 9Baking Soda 12Household Ammonia

ACID RAIN MOVIEAcid Rain - Our Changing Planet UMAC

When precipitation goes below pH 5.6.

Comes from burning of fossil fuels (cars, factories, airplanes). Sulfur and nitric oxides form sulfuric acid and nitric acid.

Main Pollutant of Acid Rain

Forest Destroyed by Acid Rain

Canada U.S.

Not just in US.China Guangzhou Shajiao on the Pearl River India Korba

England

Effects on WildlifeGenerally, the young of most species are more sensitive to environmental conditions than adults. At pH 5, most fish eggs cannot hatch. At lower pH levels, some adult fish die. Some acid lakes have no fish.

Young fish

Wuhan dead fish (China)

Acid Rain Stream

Norilsk, in Russia's remote Artic region, is accused of being world's largest producer of acid rain.