Презентация на тему: Nitrogen

Реклама. Продолжение ниже
Nitrogen
Nitrogen’s triple bond
Nitrogen
Nitrogen
Forms of Nitrogen
How can we use N 2 ?
Nitrogen Fixation (N 2 --> NH 3 or NH 4 + )
Nitrogen Fixation
Nitrogen Fixation N 2 --> NH 3 or NH 4 +
Ammonification or Mineralization
Nitrogen Mineralization also called Ammonification Organic N --> NH 4 +
Nitrification
Nitrification NH 3 or NH 4 + --> NO 2 - --> NO 3 -
Denitrification
Denitrification NO 3 - --> N 2
Denitrification
Nitrogen
Nitrous oxide N 2 O
N 2 O/O 2 sedation
Nitrogen
Nitrogen
Nitrogen
Cumulative effect
- Other Effects on Climate
Climate Change - Other Effects on Climate
- Other Effects on Climate
- Other Effects on Climate
- Other Effects on Climate
Climate Change - Other Effects on Climate
Outdoor Air Pollution Can Temporarily Slow Atmospheric Warming
Feedback Effect
An example of positive feedback
An example of negative feedback
Nitrogen
1/34
Средняя оценка: 4.8/5 (всего оценок: 69)
Код скопирован в буфер обмена
Скачать (1029 Кб)
Реклама. Продолжение ниже
1

Первый слайд презентации: Nitrogen

(N) is an essential component of DNA, RNA, and proteins, the building blocks of life. All organisms require nitrogen to live and grow. The majority (78%) of the Earth’s atmosphere is N 2. Nitrogen

Изображение слайда
Изображение для работы со слайдом
1/2
2

Слайд 2: Nitrogen’s triple bond

Although the majority of the air we breathe is N 2, most of the nitrogen in the atmosphere is unavailable for use by organisms. This is because the strong triple bond between the N atoms in N 2 molecules makes it relatively inert (like a noble gas).

Изображение слайда
Изображение для работы со слайдом
Изображение для работы со слайдом
Изображение для работы со слайдом
1/4
3

Слайд 3

Изображение слайда
Изображение для работы со слайдом
1/2
4

Слайд 4

R-NH 2 NH 4 NO 2 NO 3 NO 2 NO N 2 O N 2

Изображение слайда
1/1
5

Слайд 5: Forms of Nitrogen

Urea  CO(NH 2 ) 2 Ammonia  NH 3 (gaseous) Ammonium  NH 4 Nitrate  NO 3 Nitrite  NO 2 Atmospheric Dinitrogen N 2 Organic N

Изображение слайда
1/1
6

Слайд 6: How can we use N 2 ?

In order for plants and animals to be able to use nitrogen, N 2 gas must first be converted to more a chemically available form such as ammonium (NH 4 + ) or nitrate (NO 3 -). WE CAN’T! But BACTERIA & … can…

Изображение слайда
Изображение для работы со слайдом
1/2
7

Слайд 7: Nitrogen Fixation (N 2 --> NH 3 or NH 4 + )

ENVIRONMENTAL High-energy natural events which break the bond N 2 Examples: lightning forest fires hot lava flows

Изображение слайда
Изображение для работы со слайдом
1/2
Реклама. Продолжение ниже
8

Слайд 8: Nitrogen Fixation

R-NH 2 NH 4 NO 2 NO 3 NO 2 NO N 2 O N 2

Изображение слайда
1/1
9

Слайд 9: Nitrogen Fixation N 2 --> NH 3 or NH 4 +

How? HUMAN IMPACT Burning fossil fuels, using synthetic nitrogen fertilizers, and cultivation of legumes all fix nitrogen.

Изображение слайда
Изображение для работы со слайдом
1/2
10

Слайд 10: Ammonification or Mineralization

R-NH 2 NH 4 NO 2 NO 3 NO 2 NO N 2 O N 2

Изображение слайда
1/1
11

Слайд 11: Nitrogen Mineralization also called Ammonification Organic N --> NH 4 +

Decay of dead things, manure, etc. Done by decomposers (bacteria, fungi, etc.) During this process, a significant amount of the nitrogen contained within the dead organism is converted to ammonium (NH 4 + ).

Изображение слайда
Изображение для работы со слайдом
1/2
12

Слайд 12: Nitrification

R-NH 2 NH 4 NO 2 NO 3 NO 2 NO N 2 O N 2

Изображение слайда
1/1
13

Слайд 13: Nitrification NH 3 or NH 4 + --> NO 2 - --> NO 3 -

(Nitrifying) Bacteria add oxygen to nitrogen in two steps : STEP 1: Bacteria take in NH 3 or NH 4 + & make NO 2 - = nitrite Step 2: Bacteria take in NO 2 - & make NO 3 - = nitrate

Изображение слайда
Изображение для работы со слайдом
1/2
14

Слайд 14: Denitrification

R-NH 2 NH 4 NO 2 NO 3 NO 2 NO N 2 O N 2

Изображение слайда
1/1
Реклама. Продолжение ниже
15

Слайд 15: Denitrification NO 3 - --> N 2

(Denitrifying) Bacteria do it. Denitrification removes nitrogen from ecosystems, and converts it back to atmospheric N 2.

Изображение слайда
Изображение для работы со слайдом
1/2
16

Слайд 16: Denitrification

Removes a limiting nutrient from the environment 4NO 3 - + C 6 H 12 O 6  2N 2 + 6 H 2 0 Inhibited by O 2 Not inhibited by ammonia Microbial reaction Nitrate is the terminal electron acceptor

Изображение слайда
1/1
17

Слайд 17

Изображение слайда
Изображение для работы со слайдом
1/2
18

Слайд 18: Nitrous oxide N 2 O

Nitrous oxide, commonly known as  laughing gas,  nitrous,  nitro, or  NOS  is a  chemical compound  with the  formula   N 2 O. At room temperature, it is a colorless, odorless  non-flammable   gas, with a slightly sweet taste. It is used in  surgery and   dentistry  for its   anaesthetic  and  analgesic  effects. It is known as "laughing gas" due to the  euphoric  effects of inhaling it, a property that has led to its  recreational use  as a  dissociative   anaesthetic. It is also used as an  oxidizer  in  rocket propellants, and in  motor racing  to increase the power output of  engines. At elevated temperatures, nitrous oxide is a powerful oxidizer similar to molecular oxygen. Nitrous oxide gives rise to  nitric oxide  (NO) on reaction with oxygen atoms, and this NO in turn reacts with  ozone. As a result, it is the main naturally occurring regulator of  stratospheric  ozone.

Изображение слайда
Изображение для работы со слайдом
Изображение для работы со слайдом
1/3
19

Слайд 19: N 2 O/O 2 sedation

It is necessary to use oxygen with nitrous oxide so that the blood remains appropriately oxygenated. A mixture of 20% nitrous oxide and 80% oxygen has the same analgesic equipotence as 15 mg of morphine.

Изображение слайда
1/1
20

Слайд 20

Nitrous oxide can be used as an  oxidizer  in a  rocket  motor In vehicle  racing, nitrous oxide (often referred to as just " nitrous ") allows the engine to burn more fuel by providing more oxygen than air alone, resulting in a more powerful combustion. The gas itself is not flammable at a low pressure/temperature, but it delivers more  oxygen  than atmospheric air by breaking down at elevated temperatures. Therefore, it is often mixed with another fuel that is easier to deflagrate.

Изображение слайда
1/1
21

Слайд 21

The gas is approved for use as a  food additive  (also known as E942), specifically as an  aerosol spray propellant. Its most common uses in this context are in aerosol  whipped cream  canisters,  cooking sprays, and as an inert gas used to displace oxygen, to inhibit bacterial growth, when filling packages of  potato chips  and other similar snack foods.

Изображение слайда
1/1
22

Слайд 22

Of the entire   anthropogenic  N 2 O  emission (5.7 teragrams  N 2 O-N per year ), agricultural soils provide 3.5 teragrams  N 2 O–N per year. Nitrous oxide is produced naturally in the soil during the microbial processes of   nitrification,  denitrification, nitrifier denitrification and others. The production of  adipic acid  is the largest source to nitrous oxide.  It specifically arises from the degradation of the  nitrolic acid intermediate derived from nitration of cyclohexanone.

Изображение слайда
1/1
23

Слайд 23: Cumulative effect

Recent experiments show that interaction between water vapor, N 2 O and cosmic radiation increases cloud production.

Изображение слайда
1/1
24

Слайд 24: Other Effects on Climate

Tropospheric Ozone Anthropogenic emissions have lead to increase Increases are heterogeneous, plus hard to determine pre-industrial concentrations Stratospheric Ozone Loss in Stratosphere leads to cooling (more loss of energy out to space) However, loss of stratospheric ozone also leads to greater UV absorption (and heating) in troposphere As ozone loss is reversed, some heating may occur

Изображение слайда
1/1
25

Слайд 25: Climate Change - Other Effects on Climate

Aerosols Light Scattering Aerosol Light Absorbing Aerosol Indirect Effects of Aerosol

Изображение слайда
1/1
26

Слайд 26: Other Effects on Climate

Aerosol Effects – Light Scattering Aerosol Aerosol particles of diameter 0.2 to 1 m m is very efficient in scattering light A significant fraction is scattered in the backwards direction, so this effectively increases planetary albedo Increase in albedo leads to cooling Notice how smoke from Star fire is whiter vs. forest background

Изображение слайда
Изображение для работы со слайдом
1/2
27

Слайд 27: Other Effects on Climate

Aerosol Effects – Light Absorption Most aerosol constituents do not absorb significantly in the visible region (where light is most prevalent) A big exception is soot (elemental carbon emitted in inefficient combustion) Soot clouds lead to atmospheric warming (even if cooling the surface over short-term) Notice how smoke from Kuwait oil fires is black vs. desert background http://www.lpi.usra.edu/publications/slidesets/humanimprints/slide_16.html

Изображение слайда
Изображение для работы со слайдом
1/2
28

Слайд 28: Other Effects on Climate

Indirect Effect of Aerosols One type is through modification of cloud reflectivity Clean Case: fewer but larger droplets Polluted Case: more but smaller droplets

Изображение слайда
1/1
29

Слайд 29: Climate Change - Other Effects on Climate

Indirect Effect of Aerosols Larger droplets reflect light more poorly per g of cloud water Polluted clouds look whiter from space Source: http//www-das.uwyo.edu/~geerts/cwx/notes/chap08/contrail.html Ship tracks are indicative of localized pollution Most apparent where: clouds are normally clean and with thin clouds (thick clouds have high albedos regardless)

Изображение слайда
1/1
30

Слайд 30: Outdoor Air Pollution Can Temporarily Slow Atmospheric Warming

Aerosol and soot pollutants Can enhance or counteract projected global warming Sulfate particles reflect sunlight Soot particles absorb sunlight Outdoor Air Pollution Can Temporarily Slow Atmospheric Warming

Изображение слайда
1/1
31

Слайд 31: Feedback Effect

The climate system is very complicated. A change in one component of the system may cause changes in other components. Sometimes the changes in other components enhance the initial change, then we say that these changes have positive feedback to the system. If the changes result in the reduction of the original change, then they have negative feedback. Both positive and negative feedback processes may exist in the climate system. In studying the global climatic change, we cannot make conclusions based on intuition, but have to take all such possible complicated effects into account. A good climate model would have treated all of them realistically.

Изображение слайда
1/1
32

Слайд 32: An example of positive feedback

When the climate becomes warmer (either due to the increase of CO 2 in the atmosphere or other unknown mechanisms), the ocean may also become warmer. A warmer ocean has lower solubility of CO 2 and hence will release more CO 2 into the atmosphere. This may cause the climate to become even warmer than before. Thus the dependence of solubility of CO 2 on temperature has a positive feedback on the climate system.

Изображение слайда
1/1
33

Слайд 33: An example of negative feedback

Consider a clear region over the ocean. Since there is no cloud, the sun shines on the ocean surface, causing it to warm up. This makes this part of the ocean warmer than other parts and the air over it tends to rise (causing convection). Rising air expands and cools, causing clouds to form. The formation of clouds will block out the sun and the solar heating of the ocean surface will cease. The surface will start to cool down. Thus the cloud formation due to surface heating and convection is a negative feedback to the climate system.

Изображение слайда
1/1
34

Последний слайд презентации: Nitrogen

Atmospheric Feedbacks Increased CO 2 Higher temperature More water vapor POSITIVE NEGATIVE More water vapor & other changes Increased cloud cover More reflected solar radiation Lower temperature Less water vapor More absorbed infrared radiation Higher temperature More water vapor + + + + + –

Изображение слайда
1/1