phosphorus cycle.ppt

7/27/2019 Phosphorus Cycle.ppt

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The Phosphorus Cycle


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Basic Chemistry

Essential element of life

Phosphorus is a Group 15 (5A)

element Symbol: P

Atomic number: 15

Atomic mass: 30.974 Color: colorless/ red/ silvery white


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Basic Chemistry continued

Nonmetal

Density: 1823 kg/m3

Atomic radius: 100 pm

Solid

Melting Point: 317.3 K

Boiling Point: 550 K


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Basic Chemistry continued

Key ingredient to plants fertilizers

In nature, Phosphorus exists inform of Phosphate


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Basic Chemistry, cont.

Formulas of rocks containingphosphate are fluoroapatite

(3Ca3(PO4)2.CaF2),chloroapaptite,(3Ca3(PO4)2.CaCl2), andhydroxyapatite(3Ca3(PO4)2.Ca(OH)2)


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http://www.chemicalelements.com/elements/p.htmlhttp://www.chemicalelements.com/elements/p.html


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Description of Phosphorus

Most common form of phosphorus isred and white.

Both are tetrahedral groups of four

atoms.White phosphorus burns on contact

with air and can change into red

phosphorus when exposed to light orheat.


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http://en.wikipedia.org/wiki/Image:P%2C15.jpg


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http://www.chemsoc.org/viselements/hires/phosphorus_2.jpg


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Description of Phosphorus Cont.

White phosphorus has twomodifications.

Ordinary phosphorus is waxy

white solid.

When pure it is colorless and

transparent.


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Description, Cont.

Pure phosphorus is insoluble in

water but soluble in carbon

disulphideCatches fire spontaneously in air.


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Background

Very poisonousNever found in free nature

Essential ingredient of all cell

protoplasm, nervous tissue, and bones

Most commonly found as phosphates

Part of DNA materials and energydistribution


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Uses of Phosphorus

Used to make waterproof matches,pyrotechnics, smoke screens, tracer

bullets, and incendiary shells.

Used in fertilizer

Used to produce special glasses,

for example sodium lamps


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Uses, continued

Calcium Phosphate is used to createfine Chinaware

Monocalcium Phosphate used to

make baking powderUsed in making steel, and Phosphor

Bronze

Na3PO4 is used as a cleaning agent,water softener, and also preventscorrosion in pipes


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Hazards and Risks

Severely toxic

White form is more toxic than red form

Chronic poisoning leads to necrosis ofjaw (phossy-jaw)

Phosphate pollution comes from

detergents, insecticides, and fertilizers

Inorganic phosphorus is harmless


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Background

The phosphorus cycle does not

have a gas phase, but small

amounts of phosphoric acid riseinto the atmosphere, contributing

to acidic precipitation.


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Background

The water, carbon, and sulfurcycles all include at least one phase

in which the element is in its

gaseous state. The largest reservoir

of phosphorus is in sedimentary

rock.


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http://www.chemsoc.org/viselements/pages/data/phosphorus_data.html


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The Cycle
http://www.bio.miami.edu/dana/%20160/phosphoruscycle.gifhttp://www.bio.miami.edu/dana/%20160/phosphoruscycle.gif


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Description of Cycle

Simplest of the cycles

Phosphorus has only one form

phosphate

Always part of an organism,

dissolved in water, or in the formof rock


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Description of Cycle

Phosphorus enters environmentfrom rocks or deposits

Apatite is the phosphate rock

where phosphate is availableWeathering and erosion releasesphosphate ions that are soluble inwater


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http://soils1.cses.vt.edu/ch/biol_4684/Cycles/Pcycle.html


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Description, cont.

Phosphate then acts as fertilizers ornutrients for land plants

It gets incorporated into moleculesessential for life like ATP,adenosine triphosphatethis is

important in storage and use ofenergy


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Description, cont.

Phosphate is in backbone of DNA

and RNA

When animals and plants die,phosphates will return to the soils

or oceans again during decay


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Description, cont.

Phosphorus cycles through plantsand animals much faster than it

does through rocks and sediments..A lot of phosphate goes into the

water from erosion and leaching

Water plants use this phosphate asnutrients


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Description, cont.

Phosphate is the limiting agent in

growth of plants and algae

If there is a lack of phosphate,plants grow slowly or are stunted

If too much, excess growth mayoccur


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Description, cont.

Phosphate in water is precipitated from

water as ion phosphate (insoluble)

Phosphate in shallow sediment may berecycled into water

In deep sediment in water, it is

available as part of as part of rockformations for cycle to repeat


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Description, cont.

After that, phosphorus will end upin sediments or rock formations

again, remaining there for millionsof years.

Eventually, phosphorus is released

again through weathering and thecycle starts over.


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http://www.elmhurst.edu/~chm/vchembook/308phosphorus.html


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http://www.elmhurst.edu/~chm/onlcourse/chm110/outlines/images/phosphateag.GIF


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Human Influences on Cycle

Human influences on phosphatecycle mostly comes from

introduction & use of commercialsynthetic fertilizers.

Phosphate obtained by mining at

certain deposits of calciumphosphate called apatite.


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Influences cont.

Phosphate rock and sulfuric acid

are combined to make a fertilizer

called super phosphate.There are many negative effects of

using this fertilizer.


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Influences cont.

A lot of the fertilizer is lost through

the water run-off because plants

arent able to use up all of it.Eventually the wasted phosphate in

the water is precipitated as it settles

at the bottom of the body of water.


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Influences cont.

In some lakes & ponds the

phosphate can be recycled as a

problem nutrient.Other sources of phosphate are in

out flows from local sewage

treatment plans.


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http://www.theodoregray.com/PeriodicTable/Tiles/015/s8.JPGhttp://www.webelements.com/webelements/elements/text/P/key.html


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Interesting Facts

Originally, phosphorus was

extracted from urine.

Highly energy intensive.

Gr. phosphoros, meaning light

bearer


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Facts, cont.

In 1669, German alchemist Henning

Brand discovered phosphorus from a

preparation from urine. The only correct spelling of the

element is phosphorus. There does

exist a word phosphorous, but it is theadjectival form for the smaller valency


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Bibliography

Nutrient Cycling in Ecosystems.

http://home.earthlink.net/~dayvdan

ls/ecosys4.htm 17 September 2004Phosphorus.

http://pearl1.lanl.gov/periodic/elem

ents/15.html 17 September 2004
http://home.earthlink.net/~dayvdanls/ecosys4.htmhttp://home.earthlink.net/~dayvdanls/ecosys4.htmhttp://pearl1.lanl.gov/periodic/elements/15.htmlhttp://pearl1.lanl.gov/periodic/elements/15.htmlhttp://pearl1.lanl.gov/periodic/elements/15.htmlhttp://pearl1.lanl.gov/periodic/elements/15.htmlhttp://home.earthlink.net/~dayvdanls/ecosys4.htmhttp://home.earthlink.net/~dayvdanls/ecosys4.htm


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Bibliography cont.

Web-Elements.http://www.webelements.com/webelements/elements/text/P/key.html 17

September 2004 http://en.wikipedia.org/wiki/Phosphoru

s 17 September 2004

Virtual Chembook.http://www.elmhurst.edu/~chm/vchembook/308phosphorus.html 17September 2004
http://www.webelements.com/webelements/elements/text/P/key.htmlhttp://www.webelements.com/webelements/elements/text/P/key.htmlhttp://en.wikipedia.org/wiki/Phosphorushttp://en.wikipedia.org/wiki/Phosphorushttp://www.elmhurst.edu/~chm/vchembook/308phosphorus.htmlhttp://www.elmhurst.edu/~chm/vchembook/308phosphorus.htmlhttp://www.elmhurst.edu/~chm/vchembook/308phosphorus.htmlhttp://www.elmhurst.edu/~chm/vchembook/308phosphorus.htmlhttp://en.wikipedia.org/wiki/Phosphorushttp://en.wikipedia.org/wiki/Phosphorushttp://www.webelements.com/webelements/elements/text/P/key.htmlhttp://www.webelements.com/webelements/elements/text/P/key.html

phosphorus cycle.ppt

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