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Science 9 – Unit C – Environmental Chemistry – FITB Notes

Section 1.1 – Chemicals in the Environment Changes in the Environment � Our environment may offer _____ for disease � Environmental chemistry studies the processes and activities that change ________ in the

natural environment (both natural and man-made) � Natural processes that change chemicals include forest fires, volcanoes, and the ________

______ � Man-made (______________) processes include fossil fuel combustion, smelting,

farming, etc. The Nitrogen Cycle � Animals need complex nitrogen compounds, which are obtained by consuming _____ � Plants make _______ nitrogen (N) compounds for growth & reproduction � Plants cannot use “free nitrogen” (N2 in air), but use simple nitrogen (“fixed nitrogen”)

compounds made by ____________ bacteria in the soil � Bacteria in the soil convert “free nitrogen” into ______ nitrogen compounds (“fixed

nitrogen”) � Sequence: 1) _______ combine “free nitrogen” with elements to make ________ nitrogen

compounds 2) _____ consume simple nitrogen compounds and produce ________ nitrogen

compounds 3) ______ consume complex nitrogen compounds and produce ______ nitrogen

compounds 4) Both animals and plants release nitrogen ____ compounds back into the environment 5) __________ in the soil consume nitrogen waste and change it into “free nitrogen”

(___) 6) ______ in the soil are able to begin the cycle all over again (steps 1 to 5) Fertilizers � Simple nitrogen compounds (ex. ______) are used by farmers to skip step __ of the

nitrogen cycle � Nitrates are simple nitrogen compounds (fixed nitrogen) that are sold in ____ fertilizers � Fertilizers are mixtures of compounds that are targeted at increasing the _____ of

certain parts of a plant � Too much fertilizer can harm the plant, or _____ into water systems to harm other

organisms � Fertilizer labels tell us the mass __________ of nitrogen, phosphorus and potassium in a

mixture � The order is as follows (MEMORIZE!):

Nitrogen – Phosphorus - Potassium ex. “15-30-15” on a pack of fertilizer would tell us the pack contains: 15% _______,

30% _________, and ___ potassium � More recent labels also include _______

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Pesticides and DDT � ____ are organisms that are considered harmful to humans, other organisms or structures � Pesticides are chemicals designed to kill ____, insects or fungi � Pesticides are divided into three areas: 1) __________ are used to eradicate weeds 2) __________ are used kill insect species 3) __________ are used to eliminate a fungus � Pesticides that are incorrectly used can stay in the environment too long, causing

_________ damage � Dichloro-Diphenyl-Trichloroethane (DDT) and ______ were both used as insecticides

against mosquitoes in the 20th century � Mosquitoes transmitted diseases such as ______ � DDT is harmless in _____ concentrations, but is considered a pollutant because it does

not easily decompose or go away � DDT was discontinued because it takes _________ to breakdown, so it remains in

organisms � As DDT accumulates up the food chain through _____________, its concentration

increases � At a high enough concentration, it begins to affect the _________ cycle of an organism � DDT is mostly _______, but some tropical countries still use it (it may also be in food

exports) Fossil Fuels � Fossil fuels are __________ substances made from dead plants and animals, millions of

years ago ex. coal, oil and natural gas � Fossil fuel hydrocarbons undergo combustion with ______ � The products are always ___________ (CO2) and _____ (H2O), both of which are

greenhouse gases � _______ (CH4) is a more powerful greenhouse gas � ______ gas is composed of several fossil fuel gases, including methane � If natural gas contains deadly ________________ (H2S) gas, it is called “sour” gas

� Sour gas kills workers every year because they do not use their ________ equipment Solid Waste Disposal � When we get rid of _______, we often introduce chemicals into the environment � Some waste is incinerated at high temperatures, which can cause greenhouse gas

_________ � Other waste may be reused or _______ � Any remaining waste is put into landfill sites, and buried to ________ biodegrade Sanitary Landfill � Sanitary landfill isolates hazardous chemicals using: 1) _________ (packed) clay 2) ______ liners (sheets) � This forms an underground ________

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Sewage � Sewage is wastewater that contains both: 1) ________ substances (cannot be filtered), and 2) _________ substances (can be filtered) � Sewage _________ plants remove both dissolved and undissolved harmful substances from wastewater � Septic tanks use bacteria to break down ______ molecules in wastewater � _______ is treated wastewater that is released back into streams and lakes (a.k.a. “grey

water”) � Storm sewers are large pipes that take ________ directly to rivers and lakes (without

treatment) � Future sewage treatment plants are likely to use bacteria to do the following: 1) Clean _________ 2) Produce ________

Section 1.2 – Acids and Bases

Acids, Bases and Neutrals � Acids and bases are pure substances that can _______ in water to form acidic or basic

solutions � Acids and bases are found in everyday life: ex. ACIDS: citric acid in orange juice, acetic acid in vinegar, carbonic acid and phosphoric

acid in pop, sulphuric acid in car batteries, etc. ex. BASES: sodium hydroxide in cleaners, ammonia in cleaners, calcium carbonate in

antacid � Neutral substances have __________ properties: ex. sodium chloride table salt, pure water, magnesium sulphate in epsom bath salts, sugar

(sucrose) Observable Acid-Base Properties � Acids taste ____, while bases taste ____ � Bases feel _______ to the touch (react with oils) � Since we rarely taste or feel chemicals, we rely on chemical ________ tests

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� A chemical indicator is a substance that changes ______ when exposed to an acid or base

� ______ paper is a simple yes/no test for acidic, basic and neutral compounds ($2 test) � Litmus mixture is made of plant and _____ extracts, in two different colours (red and

blue) � The three results when testing with both colours: 1) Acid – ____ paper stays ____; ____ turns ____ 2) Base – ____ paper stays ____; ____ turns ____ 3) Neutral – ____ stays ____; ____ stays ____ � Tip: an aciD is reD; a Base is Blue The pH Scale � The pH scale is logarithmic (101, 102, 103, etc.); it tells us the ___ ion concentration in

solution � A pH range of _______ is a strong acid ex. H2SO4 in a car battery

� A pH range of _______ is a strong base ex. NaOH in liquid drain cleaner � A pH of __ is a neutral substance ex. pure H2O

� A weak ____ has a pH of 0.6 to 6.9; a weak ____ has a pH of 7.1 to 13.4 � Litmus tells us only whether a substance or solution is acidic, basic or neutral � __________ or __________ indicator are mixtures of many indicators, telling us the

approximate pH � A pH meter will tell us the _____ pH to several decimal places (ex. pH of 1.26 is an acid) Acid Rain � ________ produces toxic chemical emissions such as SO2, SO3, NO2 and CO2 gases

� When these gases combine with water in the atmosphere, _________ may form � Acid rain could be sulphurous acid, sulphuric acid, nitrous acid, nitric acid or carbonic acid � pH of acid rain could be as low as __ (corrosive) � The production of acid rain from emissions and water is called ________________ � In colder environments, __________ is also possible, often leading to spring acid shock � Acid rain can kill organisms on land or in water, and destroys __________ structures � Acid rain weakens the _______ shell of unborn organisms, causing eggs to break before

hatching � The danger from acid rain and snow is so great that older structures are being protected

now, using metal plating, inert gases and ____________ Acid-Base Neutralization � Lakes in Canada are protected from acid rain and snow by crushed limestone leftover from

______ � The limestone (calcium carbonate) is a base that ________ acids in acid-base

neutralization � When an acid and base neutralize each other, the products are always an ________ and

______ � Both products are pH _______ (pH = 7) � When limestone is added by humans, the process is called _______ � Calcium hydroxide is used in the same way

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� Calcium hydroxide also neutralizes ___________ in lakes, to form calcium sulphate salt and water

� Neutralization also occurs in our stomachs when we add _______ to neutralize leftover acid

Catalytic Converters and Scrubbers � Catalytic converters in vehicles convert harmful _____ chemicals into less harmful

ones � They use a platinum _______ to do this conversion � __________ use a sorbent (substance to capture oxides) to reduce oxide gas emissions � Scrubbers were used in the Apollo space program (__________) � The captured oxides may be converted into other less harmful substances such as

________

Section 1.3 – Common Substances Essential to Living Things

Nutrients � An organism _______ (eats) food, mixing it with enzymes (______) and increasing its

surface area (_______) � In the stomach, ____ are then mixed with the food in order to help extract vital nutrients � The nutrients may be classified into two types: organic (___________) and inorganic

(_______) Organic Nutrients � _______ __________ are complex molecules of carbon (C) and hydrogen (H) � Oxygen (O) and nitrogen (N) are present in ____ ex. sugar, paraffin wax, methane, ethanol � NOTE: _________, __________and _________ are not organic! ex. CO2 and CaCO3 are inorganic!

� Four main types of organic compounds: carbohydrates, proteins, lipids and nucleic acids Carbohydrates � Carbohydrates are organic molecules made of carbon, hydrogen and ______ ex. sugar (sucrose) � Carbohydrates are the ______ source for an organism’s metabolism (like fuel) � Found in ___, grains, potatoes and fruit � May be converted into more complex carbohydrates such as _____ and _______ Proteins from Amino Acids � Amino acids are small organic molecules made of carbon, hydrogen, oxygen and ______ � A protein is a larger organic compound made of connected ______ of amino acids (C, H,

O, and N) � Used by organisms for growth and repair of ________ � Found in meat, eggs, dairy products, nuts, beans Proteins as Enzymes � Some proteins have the purpose of speeding up chemical _______ in the body � These specific proteins are ________ (catalysts)

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� When an animal is too hot or too cold, an enzyme may change ________ and not work properly

Lipids � Lipids are organic compounds made of carbon, hydrogen and oxygen, in chains of

__________ ex. vegetable oils, nut oils, some dairy products, cooking oil, fat, lard � _______ and plants make different lipids � Carbohydrates are converted into lipids (___) when an animal has more carbohydrates

than needed Nucleic Acids and DNA � One last type of _______ molecule is a nucleic acid � Nucleic acids are made of sugars, _________, carbon, hydrogen, oxygen and nitrogen � The most __________ of organic molecules � Nucleic acids are the key building material of ____, so nucleic acids are found in all cells Vitamins � Vitamins are also organic nutrients, made of smaller ______ folded together � Many vitamins are _____-soluble, and are expelled from the body if too much is present in

the body � Some vitamins are fat-soluble and are toxic in _____ amounts � Some vitamins are ______ nutrients that an organism needs and cannot make for itself! Inorganic Nutrients � Inorganic compounds are substances ___ based on ______ � All _____ compounds are inorganic ex. ammonia, sodium bicarbonate (baking soda), quartz crystal, carbon dioxide (CO2)

� ________ are inorganic nutrients that are not destroyed by cooking or oxidation in the air Inorganic Nutrients: Minerals � There are two groups of minerals: 1) macronutrients or _____________ are needed in large amounts (>100 mg/day) 2) micronutrients or ___________ are needed in very small amounts (<100 mg/day) � It is important to understand the ideal amount of each mineral for proper ______ of an

organism � ________ amounts may harm an organism Optimum Amounts of Nutrients � Sometimes too much of one nutrient can interfere with the ________ of other nutrients ex. too much K can interfere with Mg in farmers’ crops � The optimum amount is the amount of nutrient that provides an organism with the

____ health ex. too much selenium is toxic for animals, and too little selenium causes poor immune

function � Selenium is a micromineral: _________ needed

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Section 1.4 – How Organisms Take in Substances

Digestion: Hydrolysis in Animals � _________ is the process of taking in food (“in”) � _________ is the process of breaking down food into smaller pieces, in the presence of

______ � “Hydro” means “___”; “lysis” means “______ ____” � Food is mixed with H2O, acid and enzymes

� A hydrolyzed substance is one that has been _______ by hydrolysis � In order for hydrolysis to occur properly, four things are needed (remember reaction

rate!): 1) _______ ___ (by chewing) 2) Digestive _______ (catalysts) 3) Correct acid __ 4) Correct __________ range � Animals can digest common ______ molecules: carbohydrates, lipids, protein and nucleic

acids Organisms and Substrates � A substrate is a material on which an organism: 1) ____ or moves (ex. barnacles on rocks) 2) ____ (ex. mould on cheese) � Some substrates are nutrient-___ (ex. loam soil) while others are nutrient-___ (ex. desert

sand) � Some species of red algae feed on nutrient-poor substrates, using ____________, for

most of their food

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Transport in Plants: Diffusion � Remember that concentration is the amount of a substance in a specific ______ of air,

water or soil � Three ways for plants to get water and nutrients: diffusion, osmosis and active transport � Diffusion is the movement of particles from an area of ____ concentration to an area of

____ concentration, without adding ______ ex. food colouring drops in H2O spread out quickly

Transport in Plants: Osmosis � Osmosis is the movement of water molecules (____) from wet soil into a plant’s dry roots � Osmosis is a form of diffusion, because it happens from an area of ____ water

concentration to an area of ____ water concentration � No other substances are involved, only water! � No ______ is required (since this is diffusion!) Transport in Plants: Active Transport � Active transport is the movement of substances from an area of ____ concentration to

an area of ____ concentration (low to high) � “Active” means requiring energy, so _____ must be added! � ______ molecules are transported into a cell this way (ex. carbohydrates)

Section 2.1 – Monitoring Water Quality Non-Persistent vs. Persistent Waste � All waste is potentially harmful, but some may be more harmful than others: 1) Non-Persistent – wastes that may be broken down into simple ___________

compounds by naturally-occurring chemical reactions (or by bacteria and other microorganisms)

ex. organic compounds, biological waste compounds, wood, paper, etc. 2) Persistent – wastes that __________ in the environment, breaking down over a

_____ period of time (slowly) or ___ breaking down at all ex. plastics, radioactive compounds, heavy metals like lead and mercury � The term “____________” refers to non-persistent wastes, which decompose quickly � Traditional _______ take thousands of years to decompose, so they are persistent � Newer container plastics are being made of cornstarch, and therefore ___________ waste � Some plastics are even “photodegradable,” able to be broken down by __________ � The escalating use of corn to make plastics and _______ is causing an increase in the price

of corn Monitoring of Water Quality � Remember that ________ may be dissolved or undissolved � So water that appears “____” may not be clean! � _____ means an amount harmful to organisms � There are lots of toxic substances ________ in H2O

� Regular _________ of water quality is an accurate way of keeping track of what is in water systems

� Any changes could indicate ____ water quality

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Two Indicators of Water Quality � Two indicators of water quality are: 1) Biological – changes in the _________ living in or near a water system (_____) ex. dead fish in a lake 2) Chemical – changes in the levels of _________ in a water system measured directly (_____) ex. low dissolved oxygen in the same lake Biological Indicators � Biological indicators are often the early ________ signs of a major environmental crisis ex. Dead fish may indicate low dissolved oxygen levels in a lake. What caused it? � There are two key types of organisms we monitor: 1) ____________ (ex. bacteria, fungi, etc.) 2) Aquatic invertebrates or ______________ � Invertebrates are animals without ________ � Macroinvertebrates are of five different types: 1) ____________ (ex. Crayfish, lobsters) 2) _________ (ex. clams, mussels) 3) __________ (ex. Snails, slugs) 4) ___________ (ex. worms) 5) _______ (ex. nymphs, beetles, mosquito larvae) � The levels of these may indicate aquatic health Chemical Indicators � There are six main types of chemical indicators: 1) _______________ (high O2 = healthy)

2) _______ (if pH < 5.0, fish could die) 3) ____________ (ex. lead, mercury, etc.) 4) ____________ (ex. K, N, P, Mg, etc.) 5) _________ (ex. DDT) 6) _____ (ex. NaCl, MgSO4, etc.)

Chemical Indicator: Dissolved O2 � Dissolved oxygen levels depend on four factors: __________, wind/water _________,

amount of ___________, and the _______ of organisms � Oxygen dissolves in water by ________ from the air (high concentration) to water (low

concentration) � Dissolved oxygen is removed by: 1) ____________ of organic material (rotting) 2) Cellular _________ (O2 used, CO2 produced)

� Dissolved oxygen levels may be compared with the presence of different macroinvertebrates:

� High dissolved oxygen means a ____ diversity of microorganisms and macroinvertebrates � Low dissolved oxygen content means a _____ diversity, favouring worms, snails and

insects

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Chemical Indicator: Acidity � Normal rain has a pH=___; ____ rain has a pH<5.6 � As acid concentration in a water system goes up, it reduces both plant and animal

_________! � Fish die if the pH gets as low as ___ to ___ � Acid can build up in snow and ice during ______, and then release all at once during

springtime � When this happens, ________________ can weaken the eggs of organisms, killing their

young Chemical Indicator: Heavy Metals

� Heavy metals are metals or metal substances with a density of at least __ g/cm3 or g/mL

ex. lead, copper, cadmium, mercury, etc. � Heavy metals found in large concentrations are usually due to _______ (ex. farming,

industry) � Heavy metals can disrupt normal development and proper function of the ______ system Other Chemical Indicators � If plant nutrients spill into a waterway, it causes: 1) stimulated _____ growth in the water system 2) stimulated bacteria around a plant’s _____ 3) low dissolved ___ because bacteria use it up � Pesticides are designed to be ________, remaining in the environment for a long period of

time � Addition of _________ threaten organisms that are adapted to a freshwater environment The Big Picture of Disaster � Imagine a water system full of ______ organisms � Plants in the water are stimulated by _______ nutrients such as phosphates and nitrates � Increased plant growth provides dead organic material for __________ microorganisms � This reduces the dissolved ______ in the water � The __________ population dwindles, leaving only worms, bacteria and mosquitoes and

______!

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The LD50 Dose � LD50 = the amount of a chemical

that may kill off ____ (half) of a population of organisms:

Chemical Concentration: ppm � Chemical concentration in the environment is usually measured in ______________

(ppm) � It is calculated as follows: ex. For 40 mL of solute in 40,000 mL solution:

Section 2.2 – Monitoring Air Quality Air Composition � Unpolluted dry air at sea-level (standard pressure) has the following gas composition: � _____ Nitrogen (N2)

� _____ Oxygen (O2)

� _____ Argon (Ar) � _____ Carbon dioxide (CO2)

� __________ of Ne, He, CH4 (methane), N2O, H2, CO and other gases, including H2O

gas � H and He are light enough elements to escape Earth’s gravity and _____ into space � The __________ (0 to 15 km up) is the part of the atmosphere near ground-level � The __________ (15 to 50 km up) is where large air currents and aircraft travel � In this unit, we discuss: 1) ____ rain, troposphere (Section 1.2) 2) Smoke and ___________, troposphere (here) 3) Photochemical ____, troposphere (here) 4) _________ effect, troposphere (Section 2.3) 5) Ozone _________, stratosphere (Section 2.3) Measuring Air Quality � Air quality can be measured in two different ways: 1) ______ __________ of air samples ex. analysis of bagged air samples using a gas chromatograph (GC)

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2) Determination of emissions by measurement at the source over a period of time and _________

ex. sensors in the stacks of industrial plants � _____ air measurement is a good measure of air quality in a geographic area � Different samples taken over time may allow us to see trends in air pollution � ________ may allow us to predict the amount of pollution produced by an industrial plant � This is used by governments to determine the greatest polluters

Acid Rain � Remember that in Section 1.2, we already said that the following chemicals transform into

acid rain: � ____, ____, ____, ____ � NOTE: NOx means ____ or ____ � SO2 and SO3 may each be formed by _______ reacting with oxygen

Smoke and Particulates � Solid particles in the air may include: � smoke from ______ fires, industrial activity and home heating � ____ from the ground (dust from erosion) � pollen, _______, sea salt � ___ ash (containing Hg) from coal power plants � ice ___ � Solid particles make it difficult for _______ to breath, causing respiratory distress (ex.

asthma) � Particulates also act as _______ for the different chemical reactions that cause

photochemical smog and ozone depletion (ex. dust, ice fog, etc.) � This is why the ozone layer is weakest over the South Pole (______ = catalyst)! Photochemical Smog � “Photochemical” means __________ chemical reaction � Photochemical smog further reduces air quality by producing ____ and irritating

chemicals � Reactants: _______ + ________ + _________+ __________ � Products: various smog chemicals (mostly ___) � NOTE: here, O3 refers to ground-level ozone, and “____” means a temperature of >18°C � Two areas where it can form: 1) _______ communities with lots of cars 2) _______ communities next to industrial areas � It does not take a large city to get smog pollution! � In any city, smog pollutants (NOx, CO and hydrocarbons) build up in the air before

______ � At sunrise, light and heat are introduced (which starts smog production!) � Consequences: 1) The resulting poor air quality (O3) has caused a ______ rate of respiratory illness!

2) Unused ___ means less O2 in your blood!

3) Unused ___ and ____ molecules form acid rain!

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Nitrogen oxides (NOx) � Nitrogen oxides (NO and NO2) are formed in high _____ reactions that use air (78% N2,

21% O2)

� Vehicle ______ are the highest producer of NOx

� ____-burning power plants also produce NOx � The only solution is to _______ all current vehicles with something not using high heat

reactions! ex. hydrogen fuel cells use H2 + O2 � H2O; more H2 and O2 may be made using _____

cells! Carbon monoxide (CO) � Carbon monoxide (CO) is already a concern in homes as the “_____ ______” (makes you

sleepy) � It is ________ and colourless � It forms from ___________ combustion of hydrocarbons, when there isn’t enough ___

to react to form CO2 � Well-maintained furnaces prevent this in homes � Carbon monoxide _________ warn you at home � More fuel-efficient vehicles produce ____ CO! Hydrocarbons � Vehicles use hydrocarbons (organic compounds of carbon and hydrogen) as chemical

____ � Volatile Organic Compounds (_____) are light hydrocarbons that can form

photochemical smog ex. methane, formaldehyde, benzene, etc. � VOCs are found in _____ amounts in fuel � Vehicles do not burn 100% of their fuel; ________ VOCs are released into the air via

vehicle exhaust Ground-level Ozone (O3) � Ozone (O3) is needed in the _____ stratosphere, where it makes up the ozone layer

� Ozone is the main ____ chemical at ground-level, _____ to life at high concentrations � Like CO, it is also _________ and colourless � It is detected by chemical sensors or by its ______ (asthmatics notice it first) � _________ is used in modern water treatment plants

Section 2.3 – Monitoring the Atmosphere Natural Greenhouse Effect � Greenhouse gases take some of the incoming solar radiation and re-emit it as ____

(thermal) � The heat gets _______, increasing air and water temperature � Before humanity, there was a “______ greenhouse effect” that made life for us possible on

Earth � Greenhouse gases were not meant to be a ________ � The main greenhouse gases in our atmosphere are ____ (water vapour), CO2 and CH4

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Atmospheric CO2 � Let’s look at the carbon dioxide (CO2) concentration

in the atmosphere in a ______ year: http://www.esrl.noaa.gov/gmd/ccgg/carbontracker/weather_movie.html � Pay close attention to the up-down _____ each year � In the fall and winter, CO2 is at ___ concentration

from decaying plants � In the spring and summer, CO2 is at ___

concentration from massive plant growth � Overall CO2 levels are ________ from year to year � Current CO2 data (from Mauna Loa Observatory)

http://www.esrl.noaa.gov/gmd/ccgg/trends/co2_data_mlo.html

Atmospheric Methane (CH4) � Up until recently, most of the focus has been on carbon dioxide (___)

� Late in the 20th century, methane (___) has become a large issue as well � CH4 is a powerful greenhouse gas, each molecule able to ______ more solar radiation

than CO2 � More solar radiation absorbed means ____ heat! � More heat means even more global _______! � Methane emissions are produced by the: 1) _________ industry

2) _________ industry � CH4 has been classified as “___________”,

since cattle are the largest source of methane on Earth

� Methane accounts for approximately __ to __% of current global warming

� Recent atmospheric data on CH4:

Enhanced Greenhouse Effect � Antarctic ice core samples tell us that temperature has risen sharply since the start of the

____ century � This has resulted mostly from: 1) a huge increase in CO2 from the burning of __________ hydrocarbons

2) ________ production of CH4 � This has caused the _________ greenhouse effect which will cause temperature to rise

this century! Weakening Our “Ozone Shield” � Ozone (O3) is the main product of photochemical smog at __________, harmful to life

� Ozone is produced and destroyed at the top of the Earth’s stratosphere by _________ (UV) light:

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3O2 + ___ � 2O3 2O3 + ___ � 3O2

� This happens back and forth, producing and destroying_________ tonnes of O3 a day! � Each time an O3 molecule is produced and destroyed, it absorbs ___ light!

� A type of chemical called a _______________ (CFC) releases _______ ions (Cl-) when hit by UV

� Humanity released so many CFC molecules into the upper stratosphere over the ___ 20th century

� Major CFC sources are old air conditioners, aerosol cans and _____

� Each chloride ion (Cl-) can destroy _______ ozone molecules before being neutralized, like a catalyst

� Most of this destruction occurs over the South Pole (Antarctica) because its ______ acts as a catalyst

� Most airborne chemicals travel ______ � Ozone destruction is a _______ _______ of ozone with CFC compounds � Less protective ozone means more UV light reaches us, increasing _____ rates! Global Warming vs. Ozone Depletion Q: Do greenhouse gases threaten the ozone layer? A: Greenhouse gases cause ______ _______, while ____ mainly cause the ozone layer to

deplete Q: Which one is a physical change and which is a chemical change? A: Global warming is heating of the atmosphere, so it is _______. Ozone depletion is

chemical destruction of the ozone layer, so it is _______. Q: Is water (H2O) a greenhouse gas?

A: Yes. H2O makes the difference on Earth of ___°C (without) and ___°C (with) temperature.

Q: Do some gases cause both? A: Yes. Artificially-made ____ can warm the atmosphere and destroy ozone. _____

molecules (O3) also cause natural warming.

Q: What is the major threat posed by each? A: Global warming melts glacier ice, raising _______ worldwide. Ozone depletion allows

more UV to reach the ground, causing more ______. Q: Have we stopped destruction of ozone? A: Destruction of ozone over Antarctica has stopped, with signs that our ozone layer will begin to _________ in the near future. Ice Core Data from Antarctica �New ice core data from Antarctica:

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Section 3.1 – Transport of Materials Through Air, Soil and Water

Air Transport � Chemicals may be transported by the air in 3 stages: 1) _______ at the source 2) _________ (scattering) by wind in the atmosphere 3) _________ in soil or water, by rain or snow � If there is a lot of wind, a chemical may be scattered ____ from the source � However, ___________ may deposit a chemical and stop it from dispersing any further Groundwater � _____ are the tiny spaces between soil particles � When the pores are connected in loose soil, we say the soil is _________ � When the pores are full of water, we refer to this water as ___________, the top part of

which is the ____________ � The slower the groundwater moves, the _______ the buildup in the concentration of

chemicals Surface Water � Hazardous chemicals can enter ________ water through a variety of sources: air, landfill,

hazardous industrial sites, storm sewers, etc. � Low concentrations of chemicals are usually not harmful; high concentrations of chemicals

can build up by attaching to ____ particles � Chemicals may also be ________ in air or water and be carried away from the source � Organisms may be affected by ___ concentration! Transport in Soil � Chemicals that land on soil may do one of four different things: 1) ________ away 2) be drawn up by plants or _______ by animals 3) travel down streams or ____

Temp.

CO2

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4) soak into the ground, forming a _______ � Leachates may contain __________ or heavy metals, and may undergo chemical

______ to form other harmful compounds

Section 3.2 – Changing the Concentration of Harmful Chemicals in the Environment Changing Concentration � If there is a large amount of a chemical, we say that the chemical has too ____ a

concentration � The concentration of a chemical may be reduced by one of the following: 1) Dispersion 2) Dilution 3) Biodegradation 4) Phytoremediation 5) Photolysis Dispersion � Dispersion is the _________ of a substance away from its source ex. air currents blow away smoke ex. a river carries away pollutants � The Sudbury Smelter’s stack is the largest of its kind in the world, capable of sending

emissions directly into the ___________, where they scatter Dilution � Dilution involves reducing a chemical’s concentration by adding extra __________ ex. dumping of toxins into a lake or ocean � Most ________ plants are built near rivers and oceans for this reason Biodegradation � Biodegradation is the destruction of pollutants by __________ � Bacteria in soil and water are either: 1) _______ – oxygen-consuming bacteria, or 2) _________ – oxygen-producing bacteria � Anaerobic bacteria are poisoned by locations with ____ oxygen concentration (ex. normal

air) � Aerobic bacteria die in a ___ oxygen environment � During winter, biodegradation _________ � Factors that affect the rate of biodegradation: 1) temperature (____ speeds it up) 2) soil ________ (water is needed for life) 3) ___ (acidity) 4) ______ (aerobic love it; anaerobic hate it) 5) available _______ (food) � Bioreactors also biodegrade _______ chemicals Phytoremediation � One way is to plant rows of ________ � Phytoremediation uses growing _____ to soak up chemicals

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� Plants are harvested and burned or composted, or the chemicals are _______ ex. sunflowers were used to remove radioactive materials from the soil at Chernobyl,

Ukraine Photolysis � Photolysis uses ____ to break down chemicals � “Photo” means “____” � “Lysis” means “__________” ex. ozone, smog, photodegradable plastics � Each ________ needs a specific method to clean it up; photolysis is not suitable for all

chemicals

Section 3.3 – Hazardous Chemicals Affect Living Things Biomagnification � Imagine a small fish absorbs a _____ amount of a chemical that is hard to get rid of (ex.

mercury, lead, DDT, PCB, etc.) � A larger fish stays alive for a ________, eating many of the smaller fish (containing the

chemical) � The chemical builds up in ___________ in the larger fish (ex. salmon, tuna) � Biomagnification is the increase of a chemical’s concentration as it moves up a _____

______ Crude Oil � Crude oil may contain many different elements and compounds: 1) ____________ (ex. methane, octane) 2) _______ compounds (ex. NH3, nitrates) 3) ______ compounds 4) ______ compounds 5) Heavy _____ (ex. mercury, lead) � Crude oil is separated (______) by heating it, and cooling each component (fractional

distillation) Crude Oil Spills � Crude oil is transported around the world by large ______ ships � Unfortunately, _______ run into the same problems as ordinary ships, including sandbars � Tankers can crash, causing crude oil to spill: 1) ______ compounds usually disperse in the air or water 2) _____ compounds form “tar balls”: heavier chunks sink and lighter bits wash ashore Exxon Valdez � In 1989, Exxon Valdez crashed and spilled its entire load (_______ barrels of crude oil) � The crude oil blocked ______ from diffusing into the water, so dissolved oxygen in H2O

went down � 2% of the oil (over ____ barrels) made it ashore � 1% ________ in water, 20% was ________ in air � 50% was _________, or ________ in water

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� Using _________________, and replacement of sediment on the floor, 14% of oil was recovered

� Surface oil has been ________ (land and water): boom contains spill, skimmer collects ___

� Oil trapped in the _______ has not completely been removed

� The long-term damage to organism _________ cannot be fixed

Realities of Oil Transport � Realities: 1) oil tankers, like other ships, may _____ 2) oil pipelines rust and crack; oil wells burst from corrosion and ______ error

� In response, industry has: 1) Learned from _____ and other spills

2) Established _________ plans 3) Provided hands-on _______ to workers

Section 3.4 – Hazardous Household Chemicals Household Chemicals � Even chemicals used at home can be ________ if used or disposed of incorrectly � Hazardous household chemicals include: 1) Various cleaners 2) _______ products 3) ______ products 4) ____ 5) Pesticides and ________ 6) _________ chemicals Government Regulations � Government regulations demand the following for all chemicals: 1) ______ system 2) MSDS (________ ________ _____ ______) 3) Proper _____ identifying chemicals 4) _______ in appropriate locations, away from other chemicals they may _____ with

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5) No _____ of containers for other chemicals � New products have regulations before they are sold to provide detailed information about: 1) Intended ___ 2) Physical and chemical ________ 3) _____ ingredients 4) Instructions & _________ 5) Side effects and ___________ effects 6) _______ information � Additional storage and disposal info: p. 255 & 258 Transport and Disposal � The person or persons transporting a chemical must be ________ � Different chemicals must be kept _______, and away from the occupants of the vehicle � _______ labels should be kept attached! � Never pour a hazardous material down the sink, or into the _______ (organisms may be

harmed!) � Take wastes to a ________ waste collection site!