Environmental Chemistry Answers – Flashcards

Core: ~1800-1400mi

Mantle: ~22-1800mi

Crust: ~0-22mi

Inner core is solid (higher temp but also higher pressure)

Outer core is liquid

Core is 80% iron with nickel and other trace elements

the mantle

silicate rocks containing Mg and Fe

Mostly silica and alumina (sial) (continental)

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silica and magnesium (sima) (oceanic)

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O - 49.2%

Si - 25.7%

Al - 7.50%

Asbestosis: the asbestos fibers are inhaled and reduce lung function due to the build up of connective tissue in the lungs (auto-immune response)

Mesathelioma: a cancer of the mesothelium (the lining of many internal organs)

an amorphous solid

not a crystal lattice!!

aka Pyrex

same construction as window glass but substitute B₂O₃ for CaO

can add cations like cobalt to color the glass

may incorporate polymer fibers

glass is energy intensive but we can recycle it easily

cullet is broken glass

cement is a substance that binds other materials together made from lime (CaO) with a small amount of clay

concrete is a construction material made of a coarse aggregate of crushed rocks mixed with water and a fine aggregate such as sand

it is produced by crushing limestone, clay and coal burning

cement plants have been accused of violating the clean air act b/c some of the particulate matter gets into the atmosphere and acts as a pollutant

bronze is a copper-tin alloy with about 90% of copper

copper ores are easy to find due to distinct colors (blue/green)

bronze is a hard alloy that resists corrosion, making it very useful for tools and weapons

it was first produced ~3500 BC by mixing copper ores and tin together

Cu₂S(s) + O₂(g) --> 2Cu(s) + SO₂(g)

CuO(s) + CO(g) --> Cu(s) + CO₂(g)

SnO₂(s) + CO(g) --> 2Sn(s) + 2CO₂(g)

alloys are mixtures of elements with at least one metal

alloys are helpful because they form new materials that are useful for different tasks and are often very strong/hard

there are three ways: heating in air/with a reducing agent (like coke or carbon monoxide), processing the metals with electricity, or dissolving the reactants in water in order to treat the metal

heating is the most common and oldest way

at high temperatures at the bottom of the furnace, carbon dioxide reacts with carbon to produce carbon monoxide

C + CO₂ --> 2CO

it is this carbon monoxide which is the main reducing agent in the furnace

Fe₂O₃ + 3CO --> 2Fe + 3CO₂

in the hotter parts of the furnace, the carbon itself also acts as a reducing agent. notice that at these temperatures, the other product of the reaction is carbon monoxide, not carbon dioxide

Fe₂O₃ + 3C --> 2Fe + 3CO

the temperature of the furnace is hot enough to melt the iron which trickles down to the bottom where it can be tapped off

iron is produced with a blast furnace

you burn coke and use limestone to remove silicate impurities (forms molten slag that floats on iron)

product is moletn iron that has impurities, but can be formed easily (pig iron, cast iron)

iron is  used in steel and accounts for 95% of metal production due to this use

steel strength, hardness increases as one adds carbon

over 2% carbon and steel becomes brittle

tungsten increses melting point

nickel and chromium reduce corrosion (stainless steel)

vanadium increses strength (tools)

iron ore, coke and limestone are put into the top

the furnace is steel lined with heat resistant brick

it is 400ºC at the top and 1800ºC at the bottom

the area at teh bottom is where hot air is blasted

the ore melts in this hot chamber and falls through to the bottom where it is separated into molten slag and molten iron. there are 2 tap holes at this bottom chamber so that the molten slag and the molten iron can be taken out separately

a more active element displaces a less active element from its compounds

the higher up you go, the more reactive, an element will reduce/react with metals below it

by electrolosis

this requires significantly more energy than iron but the energy cost is mitigated by lighter products being more efficient

Hg, Pb, Cd, Cr, and As

not very toxic as condensed free elements, but their cations are very toxic and tend to bind sulfurs in protiens

used in electrical switches, amalgam fillings, and preservatives like thimerosal

it is harmful because of bio-accumulation, it accumulates in food chains and the higher up in the food chain you go, the more is present

it was used as a structural metal in ancient rome up to recent times in anything from shot, solder on food tins and water pipes, leaded gasoline, and lead oxide (yellow) glaze on dinnerware

found in the water?

it's a product of zinc smelting, present in nickel-cadmium (Ni-Cad) batteries, and pigments (Cd-yellow)

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a lethal dose is 1g

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most contamination incidents due to leakage from mining operations (so maybe contaminates water?)

pesticides

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groundwater is a major source of contamination for most people caused from leakages from mining operations

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similar to phosphorous, found together in nature

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released due to coal burning, and metal smelting operations

used in electroplating, steel alloys, and leather tanning

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groundwater contamination = source for most people

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Erin Brockovitch...case against Pacific Gas and Electric for contaminating groundwater with Cr(VI) in Hinkley, CA

tons

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gold may yeild less than an ounce per ton of gold ore and is extracted with toxic cyanide

over 50%

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recycling and reusing are important but will be difficult to maintain production levels indefinitely due to ever increasing population