when ferric chlorate was sprayed in ur hand and a knife dipped in pottasium ferrocyanate is introduced in ur hand...u can see ur hand turns red like blood oozes out through ur hands.....chek it out
SHIJUSWORLDOFCHEMISTRY
this is for all upcoming chemists
Friday 13 April 2012
simple techniques in chemistry leads to big inventions
Meissner Effect
When a superconductor is cooled to below its transitional temperature, it becomes diamagnetic: this is when something is repulsed from a magnetic field rather than drawn in to it. This discovery by Meissner has lead to the concept of frictionless transportation, as an object could be “floated” along a track rather than “attached” to it by wheels. — the principle behind metro train.......
When a superconductor is cooled to below its transitional temperature, it becomes diamagnetic: this is when something is repulsed from a magnetic field rather than drawn in to it. This discovery by Meissner has lead to the concept of frictionless transportation, as an object could be “floated” along a track rather than “attached” to it by wheels. — the principle behind metro train.......
Sunday 8 April 2012
chemistryy of water
The color of water is a subject of both scientific study and popular misconception. While relatively small quantities of water are observed by humans to be colorless, pure water has a slight blue tint that becomes a deeper blue as the thickness of the observed sample increases. The blue hue of water is an intrinsic property and is caused by selective absorptionand scattering of white light. Impurities dissolved or suspended in water may give water different colored appearances.
Contents[hide] |
[edit]Intrinsic color
For more details on this topic, see Electromagnetic absorption by water.
The intrinsic natural color of liquid water may be demonstrated by looking at a white light source through a long pipe, filled with purified water, that is closed at both ends with a transparent window. The light turquoise blue color is caused by weak absorption in the red part of the visible spectrum.[1]
For most substances, absorptions in the visible spectrum are usually attributed to excitations of electronic energy states. However, water is a simple 3-atom molecule, H2O, and all its electronic absorptions occur in the ultraviolet region of the electromagnetic spectrum and are therefore not responsible for the color of water in the visible region of the spectrum.[citation needed]
The water molecule has three fundamental modes of vibration, including two stretching vibrations of the O-H bonds which occur at v1 = 3650 cm−1 and v3 = 3755 cm−1. Absorption due to these vibrations occurs in the infrared region of the spectrum. The absorption in the visible spectrum is due mainly to the harmonic v1 + 3v3 = 14,318 cm−1, which is equivalent to a wavelength of 698 nm.[1]
Absorption intensity decreases markedly with each successive overtone, resulting in very weak absorption for the third overtone. For this reason, the pipe needs to have a length of a metre or more and the water must be purified by microfiltration to remove any particles that could produce Rayleigh scattering.[citation needed]
[edit]Color of lakes and oceans
It is a common misconception that in large bodies, such as the oceans, the water's color is blue due to the reflections from the sky on its surface.
The opportunity to visibly observe the blue color of water from land or airplanes is provided by the optical scattering of unabsorbed light from water molecules, from white sandy ocean bottoms, as well as from suspended particles in the water. The back-scattering from water molecules alone is very small and only observable in highly purified water.[citation needed]
Some constituents of sea water can influence the shade of blue of the ocean. This is why it can look greener or bluer in different areas. Water in swimming pools (which may also contain various chemicals) with white-painted sides and bottom will appear as a turquoise blue.[citation needed]
Clean water appears blue in white-tiled swimming pools as well as in indoor pools where there is no blue sky to be reflected. The deeper the pool, the bluer the water.[3]
Scattering from suspended particles also plays an important role in the color of lakes and oceans. A few tens of meters of water will absorb all light, so without scattering, all bodies of water would appear black. Because most lakes and oceans contain suspended living matter and mineral particles, known as colored dissolved organic matter (CDOM) light from above is reflected upwards. Scattering from suspended particles would normally give a white color, as with snow, but because the light first passes through many meters of blue-colored liquid, the scattered light appears blue. In extremely pure water—as is found in mountain lakes, where scattering from white-colored particles is missing—the scattering from water molecules themselves also contributes a blue color.[citation needed]
Another phenomenon that occurs is Rayleigh scattering in the atmosphere along one's line of sight: the horizon is typically 4–5 km distant and the air (being just above sea level in the case of the ocean) is at its densest. This mechanism would add a blue tinge to any distant object (not just the sea) because blue light would be scattered into one's line of sight.[citation needed]
The surfaces of seas and lakes often reflect blue skylight, making them appear bluer. The relative contribution of reflected skylight and the light scattered back from the depths is strongly dependent on observation angle.[citation needed]
[edit]Color of glaciers
Main article: Blue ice (glacial)
Glaciers are large bodies of ice and snow formed during very cold climates by processes involving the compaction of fallen snow. While snowy glaciers appear white from a distance, up close and when shielded from direct ambient light, glaciers usually appear a deep blue due to the long path lengths of the internal reflected light.[citation needed]
[edit]Color of water samples
Dissolved and particulate material in water can cause discoloration. Slight discoloration is measured in Hazen units (HU).[4] Impurities can be deeply colored as well, for instance dissolved organic compounds called tannins can result in dark brown colors, or algae floating in the water (particles) can impart a green color.
The color of a water sample can be reported as:
- Apparent color is the color of the whole water sample, and consists of color from both dissolved and suspended components.
- True color is measured after filtering the water sample to remove all suspended material.
Testing for color can be a quick and easy test which often reflects the amount of organic material in the water, although certain inorganic components like iron or manganese can also impart color.[citation needed]
Water color can reveal physical, chemical and bacteriological conditions that give them the colors. In public and domestic drinking water they can be as such: Green can represent copper leaching from copper plumbing and can also represent algae growth. Blue can represent copper also and can represent a syphoning of industrial cleaners in the tank of commodes, commonly known as backflowing. Reds can be both signs of rust from iron pipes and airborne bacteria from lakes, etc. Black water can indicate sulfur reducing bacteria growth inside of a hot water tank set at less than 120 degrees Fahrenheit. This is normally present with a strong sulfur or rotten egg odor and is easily corrected by draining the water heater and increasing the temperature to 120 or higher. Caution should be given if children or the elderly will be using the hot water. The presence of a rotten egg odor will always be in the hot water side if sulfate reducing bacteria is the cause and never in the cold water side. The color spectrum with water indicators is wide and, if learned, can make solving cosmetic, bacteriological and chemical problems easier to identify.[citation needed]
[edit]Water quality and color
The presence of color in water does not necessarily indicate that the water is not potable. Color-causing substances such as tannins may be harmless.[citation needed]
Color is not removed by typical water filters; however, slow sand filters can remove color, and the use of coagulants may also succeed in trapping the color-causing compounds within the resulting precipitate.[citation needed]
Other factors can affect the color we see:
- Particles and solutes can absorb light, as in tea or coffee. Green algae in rivers and streams often lend a blue-green color. The Red Sea has occasional blooms of red Trichodesmium erythraeum algae.[citation needed]
- Particles in water can scatter light. The Colorado River is often muddy red because of suspended reddish silt in the water. Some mountain lakes and streams with finely ground rock, such as glacial flour, are turquoise. Light scattering by suspended matter is required in order that the blue light produced by water's absorption can return to the surface and be observed. Such scattering can also shift the spectrum of the emerging photons toward the green, a color often seen when water laden with suspended particles is observed
Sunday 4 March 2012
human as chemical compination
The composition of the human body can be looked at from several different points of view.
By mass, human cells consist of 65–90% water (H2O). Oxygen therefore contributes a majority of a human body's mass. Almost 99% of the mass of the human body is made up of the six elements oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus.
About 0.85% is composed of only five elements: potassium, sulfur, sodium, chlorine, and magnesium. All are necessary to life. The remaining elements are trace elements, of which more than a dozen are thought to be necessary for life, or play an active role in health (e.g., fluorine, which hardens dental enamel but seems to have no other function).
Note that not all elements which are found in the human body in trace quantities play a role in life. Some of these elements are thought to be simple bystander contaminants without function (examples: caesium, titanium), while many others are thought to be active toxins, depending on amount (cadmium, mercury, radioactives). The possible utility and toxicity of a few elements at levels normally found in the body (aluminum) is debated. Trace amounts of cadmium and lead have had functions suggested, but are almost certainly toxic in amounts normally found in the body. There is evidence that one element normally thought a toxin (arsenic) is essential in ultratrace quantities, even in mammals. Some elements that are clearly used in lower organisms and plants (arsenic, silicon, boron, nickel, vanadium) are probably needed by mammals also, but in far smaller doses. Two halogens used abundantly by lower organisms (fluorine and bromine) are presently known to be used by mammals only opportunistically. However, a general rule is that elements found in active biochemical use in lower organisms are often eventually found to be used in some way by higher organisms.[citation needed]
Contents[hide] |
[edit]Elemental composition
Main article: Dietary mineral
The average 70 kg adult human body contains approximately 6.7 x 1027 atoms and is "composed of" 60 chemical elements. In this sense, "composed of" means that a trace of the element has been identified in the body. However, at the finest resolution, most objects on Earth (including the human body) contain measureable contaminating amounts of all of the 88 chemical elements which are detectable in nearly any soil on Earth. The number of elements thought to play an active positive role in life and augmentation of health in humans and other mammals, is about 24 or 25.[1]
The relative amounts of each element vary by individual. The numbers in the table are averages of different numbers reported by different references.
The human body is ~70% water, and water is ~11% hydrogen by mass but ~67% hydrogen by atomic percent.
Atomic number | Element | Percent of Mass[2][3][4][5] | Mass (kg)[6] | Atomic percent | Positive health role in mammals[7] | Group |
---|---|---|---|---|---|---|
8 | Oxygen | 65 | 43 | 24 | Yes (water, electron acceptor) /No (Reactive Oxygen Species) | 16 |
6 | Carbon | 18 | 16 | 12 | Yes (organic compounds are hydrocarbon derivatives) | 14 |
1 | Hydrogen | 10 | 7 | 63 | Yes (e.g. water) | 1 |
7 | Nitrogen | 3 | 1.8 | 0.58 | Yes (e.g. DNA and amino acids) | 15 |
20 | Calcium | 1.4 | 1.0 | 0.24 | Yes (e.g. Calmodulin and Hydroxylapatite in bones) | 2 |
15 | Phosphorus | 1.1 | 0.78 | 0.14 | Yes (e.g. DNA and phosphorylation) | 15 |
19 | Potassium | 0.25 | 0.14 | 0.033 | Yes (e.g. Na+/K+-ATPase) | 1 |
16 | Sulfur | 0.25 | 0.14 | 0.038 | Yes (e.g. Cysteine and Methionine) | 16 |
11 | Sodium | 0.15 | 0.10 | 0.037 | Yes (e.g. Na+/K+-ATPase) | 1 |
17 | Chlorine | 0.15 | 0.095 | 0.024 | Yes (e.g. Cl-transporting ATPase) | 17 |
12 | Magnesium | 0.05 | 0.019 | 0.0070 | Yes (e.g. binding to ATP) | 2 |
26 | Iron* | 0.006 | 0.0042 | 0.00067 | Yes (e.g. Hemoglobin) | 8 |
9 | Fluorine | 0.0037 | 0.0026 | 0.0012 | Yes/No (topically hardens teeth; toxic in higher amounts) | 17 |
30 | Zinc | 0.0032 | 0.0023 | 0.00031 | Yes (e.g. Zinc finger proteins) | 12 |
14 | Silicon | 0.002 | 0.0010 | 0.0058 | Yes (probable) | 14 |
37 | Rubidium | 0.00046 | 0.00068 | 0.000033 | No (?) | 1 |
38 | Strontium | 0.00046 | 0.00032 | 0.000033 | No (?) | 2 |
35 | Bromine | 0.00029 | 0.00026 | 0.000030 | No (?) | 17 |
82 | Lead | 0.00017 | 0.00012 | 0.0000045 | No (?) (toxic in higher amounts) | 14 |
29 | Copper | 0.0001 | 0.000072 | 0.0000104 | Yes (e.g. copper proteins) | 11 |
13 | Aluminium | 0.000087 | 0.000060 | 0.000015 | No(?) (toxic?) | 13 |
48 | Cadmium | 0.000072 | 0.000050 | 0.0000045 | No(?) (toxic in higher amounts) | 12 |
58 | Cerium | 0.000057 | 0.000040 | No | ||
56 | Barium | 0.000031 | 0.000022 | 0.0000012 | No (toxic?) | 2 |
50 | Tin | 0.000024 | 0.000020 | 6.0e-7 | No(?) | 14 |
53 | Iodine | 0.000016 | 0.000020 | 7.5e-7 | Yes (e.g. Thyroxine) | 17 |
22 | Titanium | 0.000013 | 0.000020 | No | 4 | |
5 | Boron | 0.000069 | 0.000018 | 0.0000030 | Yes (probable) | 13 |
34 | Selenium | 0.000019 | 0.000015 | 4.5e-8 | Yes/No (toxic in higher amounts) | 16 |
28 | Nickel | 0.000014 | 0.000015 | 0.0000015 | Yes(e.g. urease) | 10 |
24 | Chromium | 0.0000024 | 0.000014 | 8.9e-8 | Yes (not confirmed) | 6 |
25 | Manganese | 0.000017 | 0.000012 | 0.0000015 | Yes (e.g. Mn-SOD) | 7 |
33 | Arsenic | 0.000026 | 0.000007 | 8.9e-8 | Yes (not confirmed). Toxic in higher amounts | 15 |
3 | Lithium | 0.0000031 | 0.000007 | 0.0000015 | Yes (not confirmed). Toxic in high amounts. Useful medically (mood stabilizer). | 1 |
80 | Mercury | 0.000019 | 0.000006 | 8.9e-8 | No (toxic) | 12 |
55 | Caesium | 0.0000021 | 0.000006 | 1.0e-7 | No | 1 |
42 | Molybdenum | 0.000013 | 0.000005 | 4.5e-8 | Yes (e.g. the molybdenum oxotransferases Xanthine oxidase and Sulfite oxidase | 6 |
32 | Germanium | 0.000005 | No (?) | 14 | ||
27 | Cobalt | 0.0000021 | 0.000003 | 3.0e-7 | Yes (e.g. vitamin B12) | 9 |
51 | Antimony | 0.000011 | 0.000002 | No | 15 | |
47 | Silver | 0.000001 | 0.000002 | No (toxic) | 11 | |
41 | Niobium | 0.00016 | 0.0000015 | No | 5 | |
40 | Zirconium | 0.0006 | 0.000001 | 3.0e-7 | No | 4 |
57 | Lanthanum | 0.000137 | 8e-7 | No | ||
52 | Tellurium | 0.000012 | 7e-7 | No | 16 | |
31 | Gallium | 7e-7 | No | 13 | ||
39 | Yttrium | 6e-7 | No | 3 | ||
83 | Bismuth | 5e-7 | No | 15 | ||
81 | Thallium | 5e-7 | No (toxic) | 13 | ||
49 | Indium | 4e-7 | No | 13 | ||
79 | Gold | 0.000014 | 2e-7 | 3.0e-7 | No | 11 |
21 | Scandium | 2e-7 | No | 3 | ||
73 | Tantalum | 2e-7 | No | 5 | ||
23 | Vanadium | 0.000026 | 1.1e-7 | 1.2e-8 | Yes (not confirmed) | 5 |
90 | Thorium | 1e-7 | No (toxic) | |||
92 | Uranium | 1.3e-7 | 1e-7 | 3.0e-9 | No (toxic) | |
62 | Samarium | 5.0e-8 | No | |||
74 | Tungsten | 2.0e-8 | No | 6 | ||
4 | Beryllium | 5e-9 | 3.6e-8 | 4.5e-8 | No (toxic) | 2 |
88 | Radium | 1e-17 | 3e-14 | 1e-17% | No (toxic) | 2 |
*Iron = ~3 g in men, ~2.3 g in women
The elements needed for life are relatively common in the Earth's crust, and conversely most of the common elements are necessary for life. An exception is aluminium, which is the third most common element in the Earth's crust (after oxygen and silicon), but seems to serve no function in living cells. Rather, it is harmful in large amounts.[citation needed] Transferrins can bind aluminium.[8]
Periodic table highlighting dietary elements[9]
H | He | |||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Li | Be | B | C | N | O | F | Ne | |||||||||||
Na | Mg | Al | Si | P | S | Cl | Ar | |||||||||||
K | Ca | Sc | Ti | V | Cr | Mn | Fe | Co | Ni | Cu | Zn | Ga | Ge | As | Se | Br | Kr | |
Rb | Sr | Y | Zr | Nb | Mo | Tc | Ru | Rh | Pd | Ag | Cd | In | Sn | Sb | Te | I | Xe | |
Cs | Ba | La | * | Hf | Ta | W | Re | Os | Ir | Pt | Au | Hg | Tl | Pb | Bi | Po | At | Rn |
Fr | Ra | Ac | ** | Rf | Db | Sg | Bh | Hs | Mt | Ds | Rg | Cn | Uut | Uuq | Uup | Uuh | Uus | Uuo |
* | Ce | Pr | Nd | Pm | Sm | Eu | Gd | Tb | Dy | Ho | Er | Tm | Yb | Lu | ||||
** | Th | Pa | U | Np | Pu | Am | Cm | Bk | Cf | Es | Fm | Md | No | Lr |
The four organic basic elements | Quantity elements | Essential trace elements | Function suggested from biochemistry and handling, but no specific identified biological function in humans |
[edit]Composition by molecule type
The composition can also be expressed in terms of chemicals, such as:
- Water
- Proteins – including those of hair, connective tissue, etc.
- Fats (or lipids)
- Apatite in bones
- Carbohydrates such as glycogen and glucose
- DNA
- Dissolved inorganic ions such as sodium, potassium, chloride, bicarbonate, phosphate
- Gases such as oxygen, carbon dioxide, nitrogen oxide, hydrogen, carbon monoxide, methanethiol. These may be dissolved or present in the gases in the lungs or intestines. Ethane and pentaneare produced by oxygen free radicals.[10]
- Many other small molecules, such as amino acids, fatty acids, nucleobases, nucleosides, nucleotides, vitamins, cofactors.
- Free radicals such as superoxide, hydroxyl, and hydroperoxyl.
The composition of the human body can be viewed on an atomic and molecular scale as shown in this article.
The estimated gross molecular contents of a typical 20-micrometre human cell is as follows:[11]
Molecule | Percent of Mass | Mol.Weight (daltons) | Molecules | Percent of Molecules |
---|---|---|---|---|
Water | 65* | 18* | 1.74e14* | 98.73* |
Other Inorganics | 1.5 | N/A | 1.31e12 | 0.74 |
Lipids | 12 | N/A | 8.4e11 | 0.475 |
Other Organics | 0.4 | N/A | 7.7e10 | 0.044 |
Protein | 20 | N/A | 1.9e10 | 0.011 |
RNA | 1.0 | N/A | 5e7 | 3e-5 |
DNA | 0.1 | 1e11 | 46* | 3e-11 |
Water: Obviously the amount of water is highly dependent on the level of hydration. DNA: A human cell also contains mitochondrial DNA. Sperm cells contain less mitochondrial DNA than other cells. A mammalian red blood cell contains no nucleus and thus no DNA.
[edit]Materials and tissues
Body composition can also be expressed in terms of various types of material, such as:
- Muscle
- Fat
- Bone and teeth
- Brain and nerves
- Connective tissue
- Blood – 7% of body weight.
- Lymph
- Contents of digestive tract, including intestinal gas
- Urine
- Air in lungs
[edit]Composition by cell type
There are many species of bacteria and other microorganisms that live on or inside the healthy human body. In fact, 90% of the cells in (or on) a human body are microbes, by number[12][13] (much less by mass or volume). Some of these symbionts are necessary for our health. Those that neither help nor harm us are called commensal organisms.
[edit]See also
- Hydrostatic weighing
- Dietary mineral
- Composition of blood
- List of human blood components
- Body composition
- Abundance of elements in Earth's crust
- Abundance of the chemical elements
[edit
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