E2: Acid Deposition (UNMODIFIED)

Acids VS BasesAcids:|| The group of chemicals that donates hydrogen ions (aka protons) to another substance|| Formula = only show the donation of H+ ions by the acid Common Acids: HCl (strong) , H2SO4(strong) , HNO3 (strong), H2CO3 (weak), H2SO3 (weak),  HNO2 (weak) Bases:|| The group of chemicals that accepts hydrogen ions (aka protons) to another substance.||Common Bases: NaOH (strong), NH3 (weak), Ca(OH)2 (weak), CaO (weak), CaCO3 (weak)

Neutralization Reactions Occurs when acids react with base General equation: acids + base --> water + salt Salt = another name for ionic compound

p

pH Scale pH = measurement of the acidity of a solution  Related to the concentration of H+ ions (sometimes HNO3+) The lower the pH, the more acidic the substance is (since pH = power of H [e.g. 1.0 x 10ˆ7]) Therefore: one "unit" of pH change = 10 folds difference in acidity

Some DefinitionsAcid Deposition:|| The process by which acidic gases and precipitation leave the atmosphere.|| Dry Deposition:|| When particulates and gases = absorbed by surfaces (of plants, buildings, etc.) Wet Deposition:|| The precipitation of acid compounds from the atmosphere.||

Origins of Acid Deposition

Rain is naturally acidic Clean rain pH = 5.6 CO2 (produced via cellular respiration) reacts with water vapor in the atmosphere  CO2(g) + H2O(l) --> H2CO3(aq) Carbonic Acid = weak acid NOT CONSIDERED ACID RAIN (since it's naturally occurring)

Acid Rain caused by Environmentally Pollutants pH range = 4 - 5 Significant because of the 10 fold differences

Sulfur Oxides (SOx)How it's formed (REVIEW from Air Pollution): S(s) + O2(g) -->  SO2(g) (from combustion of fossil fuels containing sulfur impurities) SO2 + 1/2 O2 --> SO3 (oxidation of SO2) How the acid is formed:Sulfur Oxides = React with water to form acid SO2(g) + H2O(l) --> H2SO3(aq) [weak] SO3(g) + H2O(l) --> H2SO4(aq) [strong]

Nitrogen Oxides (NOx)How it's formed (REVIEW from AIR POLLUTION) N2(g) + O2(g) --> 2NO (g) (from combustion of fossil fuels in internal combustion engines within vehicles) NO + 1/2 O2--> NO2 (oxidation of NO)  How the acid is formed:ONLY NO2 REACT WITH WATER 2NO2(g) + H2O(l) --> HNO2(aq) [weak]+ HNO3(aq) [strong] 4NO2(g) + O2(g) + 2H2O(l) --> 4HNO3(aq)

Building and MaterialsErosion of Calcium Carbonate Source of CaCo3 = Marbles, Limestone (of statues, buildings, etc.) Can potentially react to form Calcium Sulfates Since calcium sulfates = soluble in water, it can be washed away (therefore erosion) Formula involved 2CaCO3(s) + 2SO2(g) + O2(g) --> 2CaSO4(aq) + 2 CO2(g) CaCO3(s) + H2SO4(aq) --> CaSO4(aq) + CO2(g) + H2O(l) Corrosion of Iron/ SteelFormula: 4Fe(s) +3O2(g) +x H2O(l) --> 2 Fe2O3•xH2O(s)

Aquatic Life Affect hatching eggs Affect gills via Al3+ (Acidic compounds from rocks = "washed away" via acid deposition) Al(OH)3(s) +3H+(aq) --> Al3+(aq) + 3 H2O Depends on tolerance levels (e.g. trouts and salmon can not survive below pH 6) Cause eutrophication

Plant Life Change chemistry of soil Important nutrients are leached out by acid rain ( K+, Mg2+ and Ca2+) Disrupt chlorophyll formation (due to decreased Mg2+) Leaching of Al3+ (which prevents absorption of water and nutrients from soil)

H

Human 

Human 

Human Health

Human Health

Human Health

Human HealthBreathing Irritates mucous membranes in the nose and throat Damage lung tissues Risk Health Conditions: Asthma, Bronchitis, Emphysema  Eye IrritationOften associated with acidic compounds in air Drinking Water Toxin ions may leach into water system (e.g. Pb+, Cu2+, Al3+) High levels of Aluminum Ions = Alzheimer’s disease

Reducing SOx EmissionsReduce emissions from coal burning industriesAlkaline Scrubbers CaCO3(s) + SO2(g) --> CaSO3(s) + CO2(g) CaO(s) + SO2(g) --> CaSO3(s) 

Reducing NOx Emissions Reduce emissions from internal combustion engines 2CO(g) + 2NO(g) --> N2(s) + 2CO2(g)

Alternative Energy SourceNon-renewable sources ≠ combustion (e.g. solar, tidal, wind, fuel cells)

Reduce Energy ConsumptionsUsing alternative transportation options (e.g. public transportation, hybrid vehicles)

Liming of Water Source Type of neutralization reaction Calcium Oxide or Calcium Hydroxide (aka lime) added to water sources Powdered lime added to early  Formula: CaO(s) + H2SO4(aq) --> CaSO4(s) + H2O(l) Ca(OH)2(s) + H2SO4(aq) --> CaSO4(s) + 2H2O(l)

Background Information

Meaning + Origins of Acid Deposition

Formation of Acid Deposition

Effects of Acid Deposition

Control Strategies