~What is the Nitrogen Cycle ?~?
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Basically nitrogen in the soil is attacked by nitrogen fixing bacteria and rhizomes and trees and other plants will absorb nitrogen into their leaves. In Fall, the leaves decay and nitrogen is released as a gas back into the atmosphere. From there it can get back into the soil or water.\n\nYou'll see in the link there that there is also denitrifying bacteria.
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N(Nitrogen), P(Phosphorus), K(Potassium)
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Do you mean water cycle?\n\nWater vapor in the air is part of the water cycle. Water vapor is a gas. Water vapor is a variable gas in the atmosphere being higher in places near water sources esp. the ocean.
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A gas refrigerator uses ammonia as the coolant, and it uses water, ammonia and hydrogen gas to create a continuous cycle for the ammonia. The refrigerator has five main parts: \n\nGenerator - generates ammonia gas \nSeparator - separates ammonia gas from water \nCondenser - where hot ammonia gas is cooled and condensed to create liquid ammonia \nEvaporator - where liquid ammonia evaporates to create cold temperatures inside the refrigerator \nAbsorber - absorbs the ammonia gas in water \n\nThe cycle works like this: \n1. Heat is applied to the generator. The heat comes from burning something like gas, propane or kerosene. \n2.  In the generator is a solution of ammonia and water. The heat raises the temperature of the solution to the boiling point of the ammonia. \n3.  The boiling solution flows to the separator. In the separator, the water separates from the ammonia gas. \n4.  The ammonia gas flows upward to the condenser. The condenser is composed of metal coils and fins that allow the ammonia gas to dissipate its heat and condense into a liquid. \n5.  The liquid ammonia makes its way to the evaporator, where it mixes with hydrogen gas and evaporates, producing cold temperatures inside the refrigerator. \n6.  The ammonia and hydrogen gases flow to the absorber. Here, the water that has collected in the separator is mixed with the ammonia and hydrogen gases. \n7.  The ammonia forms a solution with the water and releases the hydrogen gas, which flows back to the evaporator. The ammonia-and-water solution flows toward the generator to repeat the cycle.
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O2, N2 and CO2.\n\nDon't understand the last part
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nitrogen-80%, oxygen-18%, 2%trace elements
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nitrogen fixation\n\nNot sure about the details, but I think that fungi or bacteria on plant's roots do this.
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If you look at it from a aquarium, which is probably the simplist explanation.\n\nFish eat their food, whatever it may be, and produce waste. That waste decomposes into ammonia. Bacteria grow and consume the ammonia and produce Nitrites (NO2). This Nitrite is then consumed by a different bacteria which produces Nitrates (NO3). Nitrates are pretty much fertalizers for plants, and any plants you have in the aquarium will consume this for the purpose of photosynthesis. Then cycle then starts over with the fish or animals in the aquarium eating that. Other nutrients are involved of course, but that is the basis of the nitrogen cycle.
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Water, nitrogen and carbon.
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Ammonia is a chemical compound, and Excretion is to actively transport a substance outside of an area. So Ammonia Excretion is to move Ammonia outside of the cell/organism.
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Hope this helps\n\nhttp://kids.earth.nasa.gov/archive/nino/intro.html
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Photosynthesis, Respiration, Acid Rain, Carbon Cycle, Nitrogen Cycle, Ozone, Methanol, Carbonic Acid...\n\nThe sources listed are very good, some may be over your head, but, look them over.
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One of the major gases is inert-Argon, and doesnt really seem to cycle-it makes up about 1%.  The primary gas is nitrogen, a small amount of which is fixed in the roots of plants (or by symbiotic organisms in those roots) and lifeforms such as blue-green algae-it makes up about 78%.  The greatest cycling gas is oxygen, which makes up about 21%.  Free oxygen, as found in our atmosphere, is extremely rare and likely would not be found in the absence of life-Oxygen in very reactive-many elements and compounds readily oxidize, such as iron turning to rust.  On Earth, plants take in carbon dioxide and split it, using the carbon to build things such as carbohydrates- the oxygen is releases, and used by aerobic lifeforms for respiration.  The level of carbon dioxide is about 0.1%- This is also very unusual, since in other planets with an atmosphere, carbon dioxide is a major gas...again, low CO2 is probably a sign of life.  The CO2 is low because the plants use it-it is returnd to the atmosphere by respiration.
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The key word in here is the "excess nitrogen". Having said that means you will provide ENOUGH or whatever amount it takes nitrogen for the reaction. i.e., H2 is your limiting reagent.\n\nN2  + 3H2  ---->  2NH3\n\nWith 5.74 g H2,\n# of moles of H2 = 5.74 / 2 = 2.87 moles\n\nAccording to the balanced equation, every 3 moles of H2 will produce 2 mole of NH3 (provided that you supply enough N2). So,\n# of moles of NH3 produced (theoretically) = (2.87/3)*2 = 1.913 moles\n\nmass of NH3 produced (theoretically) = 1.913*(14 + 3) = 32.527 g\n\nActual yield of NH3 from the process is 21.3 g\n\n% yield = (actual yield / theoretical yield) * 100\n= (21.3 / 32.527) * 100 = 65.48%
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NH4 if the compound is not usually charged but people will tell you NH3 because that is what wikipedia says because the people who say that are too lazy to work out the problem and see that Nitrogen can also have a -4 charge. NH3 has a neutral charge and NH4 has no charge also but can also have a -1 charge. \n\nAs I said some idiot with wikipedia right above me\nIt depends on what kind of ammonia you are talking about.
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D\nCalvin cycle - regeneration of ribulose 1,5- bisphosphate\nCitric acid cycle - regeneration of oxaloacetate
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The water cycle — technically known as the hydrologic cycle — is the continuous circulation of water within the Earth's hydrosphere, and is driven by solar radiation. This includes the atmosphere, land, surface water and groundwater. As water moves through the cycle, it changes state between liquid, solid, and gas phases. Water moves from compartment to compartment, such as from river to ocean, by the physical processes of evaporation, precipitation, infiltration, runoff, and subsurface flow. Movement of water within the water cycle is the subject of the field of hydrology.