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120-526: The term geochemistry was first used by the Swiss-German chemist Christian Friedrich Schönbein in 1838: "a comparative geochemistry ought to be launched, before geognosy can become geology, and before the mystery of the genesis of our planets and their inorganic matter may be revealed." However, for the rest of the century the more common term was "chemical geology", and there was little contact between geologists and chemists . Geochemistry emerged as

240-423: A phase-transfer catalyst . Sodium content of samples is determined by atomic absorption spectrophotometry or by potentiometry using ion-selective electrodes. Like the other alkali metals, sodium dissolves in ammonia and some amines to give deeply colored solutions; evaporation of these solutions leaves a shiny film of metallic sodium. The solutions contain the coordination complex [Na(NH 3 ) 6 ] , with

360-503: A raising agent , and sodablasting . Along with potassium, many important medicines have sodium added to improve their bioavailability ; though potassium is the better ion in most cases, sodium is chosen for its lower price and atomic weight. Sodium hydride is used as a base for various reactions (such as the aldol reaction ) in organic chemistry. Metallic sodium is used mainly for the production of sodium borohydride , sodium azide , indigo , and triphenylphosphine . A once-common use

480-442: A / k . The residence time is defined as where I and O are the input and output rates. In the above example, the steady-state input and output rates are both equal to a , so τ res = 1/ k . If the input and output rates are nonlinear functions of C , they may still be closely balanced over time scales much greater than the residence time; otherwise, there will be large fluctuations in C . In that case,

600-533: A compound of sodium with the Latin name of sodanum was used as a headache remedy. The name sodium is thought to originate from the Arabic suda , meaning headache, as the headache-alleviating properties of sodium carbonate or soda were well known in early times. Although sodium, sometimes called soda , had long been recognized in compounds, the metal itself was not isolated until 1807 by Sir Humphry Davy through

720-504: A computation based on 1672 analyses of numerous kinds of rocks Clarke arrived at the following as the average percentage composition of the Earth's crust: SiO 2 =59.71, Al 2 O 3 =15.41, Fe 2 O 3 =2.63, FeO=3.52, MgO=4.36, CaO=4.90, Na 2 O=3.55, K 2 O=2.80, H 2 O=1.52, TiO 2 =0.60, P 2 O 5 =0.22, (total 99.22%). All the other constituents occur only in very small quantities, usually much less than 1%. These oxides combine in

840-421: A concentration that is a function C ( r , t ) of position and time, but it is impractical to model the full variability. Instead, in an approach borrowed from chemical engineering , geochemists average the concentration over regions of the Earth called geochemical reservoirs . The choice of reservoir depends on the problem; for example, the ocean may be a single reservoir or be split into multiple reservoirs. In

960-524: A corner of our 60 m room farthest away from the apparatus, we exploded 3 mg of sodium chlorate with milk sugar while observing the nonluminous flame before the slit. After a while, it glowed a bright yellow and showed a strong sodium line that disappeared only after 10 minutes. From the weight of the sodium salt and the volume of air in the room, we easily calculate that one part by weight of air could not contain more than 1/20 millionth weight of sodium. The Earth's crust contains 2.27% sodium, making it

1080-521: A factor of 2 compared to solar composition and Ne by a factor of 10, a surprising result since the other noble gases and the elements C, N and S were enhanced by factors of 2 to 4 (oxygen was also depleted but this was attributed to the unusually dry region that Galileo sampled). Spectroscopic methods only penetrate the atmospheres of Jupiter and Saturn to depths where the pressure is about equal to 1 bar , approximately Earth's atmospheric pressure at sea level . The Galileo probe penetrated to 22 bars. This

1200-464: A few in Uranus and Neptune. Thus, while the gas giants are primarily composed of hydrogen and helium, the ice giants are primarily composed of heavier elements (O, C, N, S), primarily in the form of water, methane, and ammonia. The surfaces are cold enough for molecular hydrogen to be liquid, so much of each planet is likely a hydrogen ocean overlaying one of heavier compounds. Outside the core, Jupiter has

1320-455: A fourth group, and in the fifth group FeO enter the magnesium silicates. The compositions of the planets and the Moon are chondritic , meaning that within each group the ratios between elements are the same as in carbonaceous chondrites. The estimates of planetary compositions depend on the model used. In the equilibrium condensation model, each planet was formed from a feeding zone in which

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1440-421: A haphazard way. For example, potash (potassium carbonate) and soda ( sodium carbonate ) combine to produce feldspars . In some cases, they may take other forms, such as nepheline , leucite , and muscovite , but in the great majority of instances they are found as feldspar. Phosphoric acid with lime (calcium carbonate) forms apatite . Titanium dioxide with ferrous oxide gives rise to ilmenite . Part of

1560-567: A high affinity for the sodium ion; derivatives of the alkalide Na are obtainable by the addition of cryptands to solutions of sodium in ammonia via disproportionation . Many organosodium compounds have been prepared. Because of the high polarity of the C-Na bonds, they behave like sources of carbanions (salts with organic anions ). Some well-known derivatives include sodium cyclopentadienide (NaC 5 H 5 ) and trityl sodium ((C 6 H 5 ) 3 CNa). Sodium naphthalene , Na [C 10 H 8 •] ,

1680-415: A high neutron flux in the reactor. The high boiling point of sodium allows the reactor to operate at ambient (normal) pressure, but drawbacks include its opacity, which hinders visual maintenance, and its strongly reducing properties. Sodium will explode in contact with water, although it will only burn gently in air. Radioactive sodium-24 may be produced by neutron bombardment during operation, posing

1800-411: A ligand contains more than one donor atom, forming very strong complexes, also called chelates (the ligand is the chelator). One of the most common chelators is EDTA ( ethylenediaminetetraacetic acid ), which can replace six molecules of water and form strong bonds with metals that have a plus two charge. With stronger complexation, lower activity of the free metal ion is observed. One consequence of

1920-430: A little more than 47% of the Earth's crust consists of oxygen . It occurs principally in combination as oxides, of which the chief are silica , alumina , iron oxides , and various carbonates ( calcium carbonate , magnesium carbonate , sodium carbonate , and potassium carbonate ). The silica functions principally as an acid, forming silicates, and all the commonest minerals of igneous rocks are of this nature. From

2040-460: A mantle of liquid metallic hydrogen and an atmosphere of molecular hydrogen and helium. Metallic hydrogen does not mix well with helium, and in Saturn, it may form a separate layer below the metallic hydrogen. Terrestrial planets are believed to have come from the same nebular material as the giant planets, but they have lost most of the lighter elements and have different histories. Planets closer to

2160-404: A nerve impulse in a process called the action potential . Sodium at standard temperature and pressure is a soft silvery metal that combines with oxygen in the air, forming sodium oxides . Bulk sodium is usually stored in oil or an inert gas. Sodium metal can be easily cut with a knife. It is a good conductor of electricity and heat. Due to having low atomic mass and large atomic radius, sodium

2280-407: A nuclear criticality accident , converts some of the stable Na in human blood to Na; the neutron radiation dosage of a victim can be calculated by measuring the concentration of Na relative to Na. Sodium atoms have 11 electrons, one more than the stable configuration of the noble gas neon . The first and second ionization energies are 495.8 kJ/mol and 4562 kJ/mol, respectively. As

2400-606: A position at the University of Basel in 1828, becoming a full professor in 1835. He remained there until his death in 1868, and was buried in Basel. In 1839, Schönbein published the principle of the fuel cell in the "Philosophical Magazine". While doing experiments on the electrolysis of water at the University of Basel, Schönbein first began to notice a distinctive odor in his laboratory. This smell gave Schönbein

2520-411: A result, chemical reactions show a small isotope dependence, with heavier isotopes preferring species or compounds with a higher oxidation state; and in phase changes, heavier isotopes tend to concentrate in the heavier phases. Mass-dependent fractionation is largest in light elements because the difference in masses is a larger fraction of the total mass. Ratios between isotopes are generally compared to

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2640-888: A result, sodium usually forms ionic compounds involving the Na cation. Metallic sodium is generally less reactive than potassium and more reactive than lithium . Sodium metal is highly reducing, with the standard reduction potential for the Na /Na couple being −2.71 volts, though potassium and lithium have even more negative potentials. Sodium compounds are of immense commercial importance, being particularly central to industries producing glass , paper , soap , and textiles . The most important sodium compounds are table salt (Na Cl ), soda ash (Na 2 CO 3 ), baking soda (Na HCO 3 ), caustic soda (NaOH), sodium nitrate (Na NO 3 ), di- and tri- sodium phosphates , sodium thiosulfate (Na 2 S 2 O 3 ·5H 2 O), and borax (Na 2 B 4 O 7 ·10H 2 O). In compounds, sodium

2760-495: A result, the committee has established Adequate Intake (AI) levels instead, as follows. The sodium AI for infants of 0–6 months is established at 110 mg/day, 7–12 months: 370 mg/day; for children 1–3 years: 800 mg/day, 4–8 years: 1,000 mg/day; for adolescents: 9–13 years – 1,200 mg/day, 14–18 years 1,500 mg/day; for adults regardless of their age or sex: 1,500 mg/day. Sodium chloride ( NaCl ) contains approximately 39.34% of elemental sodium ( Na )

2880-409: A scavenged-type trace metal is aluminium , which has strong interactions with particles as well as a short residence time in the ocean. The residence times of scavenged-type trace metals are around 100 to 1000 years. The concentrations of these metals are highest around bottom sediments, hydrothermal vents , and rivers. For aluminium, atmospheric dust provides the greatest source of external inputs into

3000-598: A separate discipline after major laboratories were established, starting with the United States Geological Survey (USGS) in 1884, which began systematic surveys of the chemistry of rocks and minerals. The chief USGS chemist, Frank Wigglesworth Clarke , noted that the elements generally decrease in abundance as their atomic weights increase, and summarized the work on elemental abundance in The Data of Geochemistry . The composition of meteorites

3120-461: A slight radiation hazard; the radioactivity stops within a few days after removal from the reactor. If a reactor needs to be shut down frequently, NaK is used. Because NaK is a liquid at room temperature, the coolant does not solidify in the pipes. In this case, the pyrophoricity of potassium requires extra precautions to prevent and detect leaks. Another heat transfer application is poppet valves in high-performance internal combustion engines;

3240-508: A small sub-group rich in olivine and without feldspar has been called the "ultramafic" rocks. They have very low percentages of silica but much iron and magnesia. Except these last, practically all rocks contain felspars or feldspathoid minerals. In the acid rocks, the common feldspars are orthoclase, perthite, microcline, and oligoclase—all having much silica and alkalis. In the mafic rocks labradorite, anorthite, and bytownite prevail, being rich in lime and poor in silica, potash, and soda. Augite

3360-556: A standard. For example, sulfur has four stable isotopes, of which the two most common are S and S. The ratio of their concentrations, R =S/S , is reported as where R s is the same ratio for a standard. Because the differences are small, the ratio is multiplied by 1000 to make it parts per thousand (referred to as parts per mil). This is represented by the symbol ‰ . Equilibrium fractionation occurs between chemicals or phases that are in equilibrium with each other. In equilibrium fractionation between phases, heavier phases prefer

3480-413: A star of at least three solar masses. Two radioactive , cosmogenic isotopes are the byproduct of cosmic ray spallation : Na has a half-life of 2.6 years and Na, a half-life of 15 hours; all other isotopes have a half-life of less than one minute. Two nuclear isomers have been discovered, the longer-lived one being Na with a half-life of around 20.2 milliseconds. Acute neutron radiation, as from

3600-408: A strong reducing agent, forms upon mixing Na and naphthalene in ethereal solutions. Sodium forms alloys with many metals, such as potassium, calcium , lead , and the group 11 and 12 elements. Sodium and potassium form KNa 2 and NaK . NaK is 40–90% potassium and it is liquid at ambient temperature . It is an excellent thermal and electrical conductor. Sodium-calcium alloys are by-products of

3720-431: A trace metal with a conservative-type distribution is molybdenum. It has a residence time within the oceans of around 8 x 10 years and is generally present as the molybdate anion (MoO 4 ). Molybdenum interacts weakly with particles and displays an almost uniform vertical profile in the ocean. Relative to the abundance of molybdenum in the ocean, the amount required as a metal cofactor for enzymes in marine phytoplankton

Geochemistry - Misplaced Pages Continue

3840-411: A type of model called a box model , a reservoir is represented by a box with inputs and outputs. Geochemical models generally involve feedback. In the simplest case of a linear cycle, either the input or the output from a reservoir is proportional to the concentration. For example, salt is removed from the ocean by formation of evaporites , and given a constant rate of evaporation in evaporite basins,

3960-621: Is a form of kinetic fractionation since reactions tend to be in one direction. Biological organisms prefer lighter isotopes because there is a lower energy cost in breaking energy bonds. In addition to the previously mentioned factors, the environment and species of the organism can have a large effect on the fractionation. Through a variety of physical and chemical processes, chemical elements change in concentration and move around in what are called geochemical cycles . An understanding of these changes requires both detailed observation and theoretical models. Each chemical compound, element or isotope has

4080-446: Is a small fraction of the planet, which is expected to reach pressures of over 40 Mbar. To constrain the composition in the interior, thermodynamic models are constructed using the information on temperature from infrared emission spectra and equations of state for the likely compositions. High-pressure experiments predict that hydrogen will be a metallic liquid in the interior of Jupiter and Saturn, while in Uranus and Neptune it remains in

4200-561: Is anomalously enriched. The pattern of elemental abundance is mainly due to two factors. The hydrogen, helium, and some of the lithium were formed in about 20 minutes after the Big Bang , while the rest were created in the interiors of stars . Meteorites come in a variety of compositions, but chemical analysis can determine whether they were once in planetesimals that melted or differentiated . Chondrites are undifferentiated and have round mineral inclusions called chondrules . With

4320-448: Is based on "educated guesses". One difficulty with this model is that there may be significant errors in its prediction of volatile abundances because some volatiles are only partially condensed. The more common rock constituents are nearly all oxides ; chlorides , sulfides and fluorides are the only important exceptions to this and their total amount in any rock is usually much less than 1%. By 1911, F. W. Clarke had calculated that

4440-403: Is convenient in a purely formal classification like that outlined here to treat the whole assemblage as a distinct series. This classification is based essentially on the mineralogical constitution of the igneous rocks. Any chemical distinctions between the different groups, though implied, are relegated to a subordinate position. It is admittedly artificial, but it has grown up with the growth of

4560-457: Is dissolved in ammonia solution, it can be used to reduce alkynes to trans- alkenes . Lasers emitting light at the sodium D line are used to create artificial laser guide stars that assist in the adaptive optics for land-based visible-light telescopes. Liquid sodium is used as a heat transfer fluid in sodium-cooled fast reactors because it has the high thermal conductivity and low neutron absorption cross section required to achieve

4680-456: Is less electropositive than sodium, no calcium will be deposited at the cathode. This method is less expensive than the previous Castner process (the electrolysis of sodium hydroxide ). If sodium of high purity is required, it can be distilled once or several times. The market for sodium is volatile due to the difficulty in its storage and shipping; it must be stored under a dry inert gas atmosphere or anhydrous mineral oil to prevent

4800-506: Is low, olivine may be expected; where silica is present in greater quantity over ferromagnesian minerals, such as augite , hornblende , enstatite or biotite , occur rather than olivine. Unless potash is high and silica relatively low, leucite will not be present, for leucite does not occur with free quartz. Nepheline , likewise, is usually found in rocks with much soda and comparatively little silica. With high alkalis , soda-bearing pyroxenes and amphiboles may be present. The lower

4920-535: Is negligible. Trace metals with nutrient-type distributions are strongly associated with the internal cycles of particulate organic matter, especially the assimilation by plankton. The lowest dissolved concentrations of these metals are at the surface of the ocean, where they are assimilated by plankton. As dissolution and decomposition occur at greater depths, concentrations of these trace metals increase. Residence times of these metals, such as zinc, are several thousand to one hundred thousand years. Finally, an example of

Geochemistry - Misplaced Pages Continue

5040-479: Is possible, by rock analysis, to say approximately what minerals the rock contains, but there are numerous exceptions to any rule. Except in acid or siliceous igneous rocks containing greater than 66% of silica , known as felsic rocks, quartz is not abundant in igneous rocks. In basic rocks (containing 20% of silica or less) it is rare for them to contain as much silicon, these are referred to as mafic rocks. If magnesium and iron are above average while silica

5160-561: Is present as the Mo(VI) oxidation state as MoO 4 (aq) in oxic environments. Mo(V) and Mo(IV) are present in reduced environments in the forms MoO 2 (aq) and MoS 2(s) . Rhenium is present as the Re(VII) oxidation state as ReO 4 within oxic conditions, but is reduced to Re(IV) which may form ReO 2 or ReS 2 . Uranium is in oxidation state VI in UO 2 (CO 3 ) 3 (aq) and is found in

5280-531: Is seen in any whose surfaces are cool enough for sodium to exist in atomic form (rather than ionised). This corresponds to stars of roughly F-type and cooler. Many other stars appear to have a sodium absorption line, but this is actually caused by gas in the foreground interstellar medium . The two can be distinguished via high-resolution spectroscopy, because interstellar lines are much narrower than those broadened by stellar rotation . Sodium has also been detected in numerous Solar System environments, including

5400-484: Is that volatiles would not condense, so the planets would have no atmospheres and Earth no atmosphere. In chondritic mixing models, the compositions of chondrites are used to estimate planetary compositions. For example, one model mixes two components, one with the composition of C1 chondrites and one with just the refractory components of C1 chondrites. In another model, the abundances of the five fractionation groups are estimated using an index element for each group. For

5520-491: Is the sixth most abundant element in the Earth's crust and exists in numerous minerals such as feldspars , sodalite , and halite (NaCl). Many salts of sodium are highly water-soluble: sodium ions have been leached by the action of water from the Earth's minerals over eons, and thus sodium and chlorine are the most common dissolved elements by weight in the oceans. Sodium was first isolated by Humphry Davy in 1807 by

5640-678: Is the most common ferromagnesian in mafic rocks, but biotite and hornblende are on the whole more frequent in felsic rocks. Rocks that contain leucite or nepheline, either partly or wholly replacing felspar, are not included in this table. They are essentially of intermediate or of mafic character. We might in consequence regard them as varieties of syenite, diorite, gabbro, etc., in which feldspathoid minerals occur, and indeed there are many transitions between syenites of ordinary type and nepheline — or leucite — syenite, and between gabbro or dolerite and theralite or essexite. But, as many minerals develop in these "alkali" rocks that are uncommon elsewhere, it

5760-549: Is the principal source of sodium ( Na ) in the diet, and is used as seasoning and preservative in such commodities as pickled preserves and jerky ; for Americans, most sodium chloride comes from processed foods . Other sources of sodium are its natural occurrence in food and such food additives as monosodium glutamate (MSG), sodium nitrite , sodium saccharin, baking soda (sodium bicarbonate), and sodium benzoate . The U.S. Institute of Medicine set its tolerable upper intake level for sodium at 2.3 grams per day, but

5880-400: Is the same as that occurring in the vicinity of lightning storms, an odor that indicates the presence of ozone in the atmosphere. Although his wife had forbidden him to do so, Schönbein occasionally experimented at home in the kitchen. One day in 1845, when his wife was away, he spilled a mixture of nitric acid and sulfuric acid . After using his wife's cotton apron to mop it up, he hung

6000-455: Is third-least dense of all elemental metals and is one of only three metals that can float on water, the other two being lithium and potassium. The melting (98 °C) and boiling (883 °C) points of sodium are lower than those of lithium but higher than those of the heavier alkali metals potassium, rubidium, and caesium, following periodic trends down the group. These properties change dramatically at elevated pressures: at 1.5  Mbar ,

6120-622: Is to melt them together and another is to deposit sodium electrolytically on molten lead cathodes. NaPb 3 , NaPb, Na 9 Pb 4 , Na 5 Pb 2 , and Na 15 Pb 4 are some of the known sodium-lead alloys. Sodium also forms alloys with gold (NaAu 2 ) and silver (NaAg 2 ). Group 12 metals ( zinc , cadmium and mercury ) are known to make alloys with sodium. NaZn 13 and NaCd 2 are alloys of zinc and cadmium. Sodium and mercury form NaHg, NaHg 4 , NaHg 2 , Na 3 Hg 2 , and Na 3 Hg. Because of its importance in human health, salt has long been an important commodity. In medieval Europe,

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6240-628: Is usually ionically bonded to water and anions and is viewed as a hard Lewis acid . Most soaps are sodium salts of fatty acids . Sodium soaps have a higher melting temperature (and seem "harder") than potassium soaps. Like all the alkali metals , sodium reacts exothermically with water. The reaction produces caustic soda ( sodium hydroxide ) and flammable hydrogen gas. When burned in air, it forms primarily sodium peroxide with some sodium oxide . Sodium tends to form water-soluble compounds, such as halides , sulfates , nitrates , carboxylates and carbonates . The main aqueous species are

6360-440: The D line at about 589.3 nm. Spin-orbit interactions involving the electron in the 3p orbital split the D line into two, at 589.0 and 589.6 nm; hyperfine structures involving both orbitals cause many more lines. Twenty isotopes of sodium are known, but only Na is stable. Na is created in the carbon-burning process in stars by fusing two carbon atoms together; this requires temperatures above 600 megakelvins and

6480-541: The Earth's crust , forming silicates and other oxides. Siderophile elements ( Fe , Co , Ni , Pt , Re , Os ) have an affinity for iron and tend to concentrate in the core . Chalcophile elements ( Cu , Ag , Zn , Pb , S ) form sulfides ; and atmophile elements ( O , N , H and noble gases) dominate the atmosphere. Within each group, some elements are refractory , remaining stable at high temperatures, while others are volatile , evaporating more easily, so heating can separate them. The chemical composition of

6600-595: The Sun . The line was first studied in 1814 by Joseph von Fraunhofer during his investigation of the lines in the solar spectrum, now known as the Fraunhofer lines . Fraunhofer named it the "D" line, although it is now known to actually be a group of closely spaced lines split by a fine and hyperfine structure . The strength of the D ;line allows its detection in many other astronomical environments. In stars, it

6720-472: The electrolysis of sodium hydroxide . In 1809, the German physicist and chemist Ludwig Wilhelm Gilbert proposed the names Natronium for Humphry Davy's "sodium" and Kalium for Davy's "potassium". The chemical abbreviation for sodium was first published in 1814 by Jöns Jakob Berzelius in his system of atomic symbols, and is an abbreviation of the element's Neo-Latin name natrium , which refers to

6840-423: The electrolysis of sodium hydroxide . Among many other useful sodium compounds, sodium hydroxide ( lye ) is used in soap manufacture , and sodium chloride ( edible salt ) is a de-icing agent and a nutrient for animals including humans. Sodium is an essential element for all animals and some plants. Sodium ions are the major cation in the extracellular fluid (ECF) and as such are the major contributor to

6960-467: The exospheres of Mercury and the Moon , and numerous other bodies. Some comets have a sodium tail , which was first detected in observations of Comet Hale–Bopp in 1997. Sodium has even been detected in the atmospheres of some extrasolar planets via transit spectroscopy . Employed in rather specialized applications, about 100,000 tonnes of metallic sodium are produced annually. Metallic sodium

7080-428: The giant planets , which are dominated by hydrogen and helium and have lower mean densities. These can be further subdivided into the gas giants ( Jupiter and Saturn ) and the ice giants ( Uranus and Neptune ) that have large icy cores. Most of our direct information on the composition of the giant planets is from spectroscopy . Since the 1930s, Jupiter was known to contain hydrogen, methane and ammonium . In

7200-483: The number of neutrons in the nucleus. The sum of these is the mass number , which is roughly equal to the atomic mass . Atoms with the same atomic number but different neutron numbers are called isotopes . A given isotope is identified by a letter for the element preceded by a superscript for the mass number. For example, two common isotopes of chlorine are Cl and Cl. There are about 1700 known combinations of Z and N, of which only about 260 are stable. However, most of

7320-558: The sixth most abundant element on Earth and the fourth most abundant metal, behind aluminium , iron , calcium , and magnesium and ahead of potassium. Sodium's estimated oceanic abundance is 10.8 grams per liter. Because of its high reactivity, it is never found as a pure element. It is found in many minerals, some very soluble, such as halite and natron , others much less soluble, such as amphibole and zeolite . The insolubility of certain sodium minerals such as cryolite and feldspar arises from their polymeric anions, which in

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7440-439: The "mafic" group. The "intermediate" rocks include those characterized by the general absence of both quartz and olivine. An important subdivision of these contains a very high percentage of alkalis, especially soda, and consequently has minerals such as nepheline and leucite not common in other rocks. It is often separated from the others as the "alkali" or "soda" rocks, and there is a corresponding series of mafic rocks. Lastly,

7560-566: The 1960s to around the year 2002 was concerned with the biochemistry of the Early Earth with a focus on isotope-biogeochemistry and the evidence of the earliest life processes in Precambrian . Some subfields of geochemistry are: The building blocks of materials are the chemical elements . These can be identified by their atomic number Z, which is the number of protons in the nucleus . An element can have more than one value for N,

7680-464: The 1960s, interferometry greatly increased the resolution and sensitivity of spectral analysis, allowing the identification of a much greater collection of molecules including ethane , acetylene , water and carbon monoxide . However, Earth-based spectroscopy becomes increasingly difficult with more remote planets, since the reflected light of the Sun is much dimmer; and spectroscopic analysis of light from

7800-462: The ECF osmotic pressure . Animal cells actively pump sodium ions out of the cells by means of the sodium–potassium pump , an enzyme complex embedded in the cell membrane , in order to maintain a roughly ten-times higher concentration of sodium ions outside the cell than inside. In nerve cells , the sudden flow of sodium ions into the cell through voltage-gated sodium channels enables transmission of

7920-478: The Earth and other bodies is determined by two opposing processes: differentiation and mixing. In the Earth's mantle , differentiation occurs at mid-ocean ridges through partial melting , with more refractory materials remaining at the base of the lithosphere while the remainder rises to form basalt . After an oceanic plate descends into the mantle, convection eventually mixes the two parts together. Erosion differentiates granite , separating it into clay on

8040-526: The Earth is composed of non-silicate minerals such as carbonates , oxides , and sulfides . The other determining factor, namely the physical conditions attending consolidation, plays, on the whole, a smaller part, yet is by no means negligible. Certain minerals are practically confined to deep-seated intrusive rocks, e.g., microcline, muscovite, diallage. Leucite is very rare in plutonic masses; many minerals have special peculiarities in microscopic character according to whether they crystallized in-depth or near

8160-523: The Egyptian natron , a natural mineral salt mainly consisting of hydrated sodium carbonate. Natron historically had several important industrial and household uses, later eclipsed by other sodium compounds. Sodium imparts an intense yellow color to flames. As early as 1860, Kirchhoff and Bunsen noted the high sensitivity of a sodium flame test , and stated in Annalen der Physik und Chemie : In

8280-471: The Sun might be expected to have a higher fraction of refractory elements, but if their later stages of formation involved collisions of large objects with orbits that sampled different parts of the Solar System, there could be little systematic dependence on position. Direct information on Mars, Venus and Mercury largely comes from spacecraft missions. Using gamma-ray spectrometers , the composition of

8400-464: The ages of 4.56 billion years, they date to the early solar system . A particular kind, the CI chondrite , has a composition that closely matches that of the Sun's photosphere, except for depletion of some volatiles (H, He, C, N, O) and a group of elements (Li, B, Be) that are destroyed by nucleosynthesis in the Sun. Because of the latter group, CI chondrites are considered a better match for the composition of

8520-404: The apron over the stove to dry, only to find that the cloth spontaneously ignited and burned so quickly that it seemed to disappear. Schönbein, in fact, had converted the cellulose of the apron, with the nitro groups (added from the nitric acid) serving as an internal source of oxygen ; when heated, the cellulose was completely and suddenly oxidized . Schönbein recognized the possibilities of

8640-689: The aquo complexes [Na(H 2 O) n ] , where n = 4–8; with n = 6 indicated from X-ray diffraction data and computer simulations. Direct precipitation of sodium salts from aqueous solutions is rare because sodium salts typically have a high affinity for water. An exception is sodium bismuthate (NaBiO 3 ), which is insoluble in cold water and decomposes in hot water. Because of the high solubility of its compounds, sodium salts are usually isolated as solids by evaporation or by precipitation with an organic antisolvent, such as ethanol ; for example, only 0.35 g/L of sodium chloride will dissolve in ethanol. A crown ether such as 15-crown-5 may be used as

8760-715: The average person in the United States consumes 3.4 grams per day. The American Heart Association recommends no more than 1.5 g of sodium per day. The Committee to Review the Dietary Reference Intakes for Sodium and Potassium, which is part of the National Academies of Sciences, Engineering, and Medicine, has determined that there isn't enough evidence from research studies to establish Estimated Average Requirement (EAR) and Recommended Dietary Allowance (RDA) values for sodium. As

8880-423: The case of feldspar is a polysilicate. In the universe, sodium is the 15th most abundant element with a 20,000 parts-per-billion abundance, making sodium 0.002% of the total atoms in the universe. Atomic sodium has a very strong spectral line in the yellow-orange part of the spectrum (the same line as is used in sodium-vapour street lights ). This appears as an absorption line in many types of stars, including

9000-463: The clue to the presence of a new product from his experiments. Because of the pronounced smell, Schönbein coined the term "ozone" for the new gas, from the Greek word "ozein", meaning "to smell". Schönbein described his discoveries in publications in 1840. He later found that the smell of ozone was similar to that produced by the slow oxidation of white phosphorus . The ozone smell Schönbein detected

9120-442: The color changes from silvery metallic to black; at 1.9 Mbar the material becomes transparent with a red color; and at 3 Mbar, sodium is a clear and transparent solid. All of these high-pressure allotropes are insulators and electrides . In a flame test , sodium and its compounds glow yellow because the excited 3s electrons of sodium emit a photon when they fall from 3p to 3s; the wavelength of this photon corresponds to

9240-425: The compositions of solids were determined by the temperature in that zone. Thus, Mercury formed at 1400 K, where iron remained in a pure metallic form and there was little magnesium or silicon in solid form; Venus at 900 K, so all the magnesium and silicon condensed; Earth at 600 K, so it contains FeS and silicates; and Mars at 450 K, so FeO was incorporated into magnesium silicates. The greatest problem with this theory

9360-404: The corrosion of porphyritic minerals in igneous rocks. In rhyolites and trachytes, early crystals of hornblende and biotite may be found in great numbers partially converted into augite and magnetite. Hornblende and biotite were stable under the pressures and other conditions below the surface, but unstable at higher levels. In the ground-mass of these rocks, augite is almost universally present. But

9480-634: The crust of Mars has been measured by the Mars Odyssey orbiter, the crust of Venus by some of the Venera missions to Venus, and the crust of Mercury by the MESSENGER spacecraft. Additional information on Mars comes from meteorites that have landed on Earth (the Shergottites , Nakhlites , and Chassignites , collectively known as SNC meteorites). Abundances are also constrained by the masses of

9600-475: The early Solar System. Moreover, the chemical analysis of CI chondrites is more accurate than for the photosphere, so it is generally used as the source for chemical abundance, despite their rareness (only five have been recovered on Earth). The planets of the Solar System are divided into two groups: the four inner planets are the terrestrial planets ( Mercury , Venus , Earth and Mars ), with relatively small sizes and rocky surfaces. The four outer planets are

9720-431: The electrolytic production of sodium from a binary salt mixture of NaCl-CaCl 2 and ternary mixture NaCl-CaCl 2 -BaCl 2 . Calcium is only partially miscible with sodium, and the 1–2% of it dissolved in the sodium obtained from said mixtures can be precipitated by cooling to 120 °C and filtering. In a liquid state, sodium is completely miscible with lead. There are several methods to make sodium-lead alloys. One

9840-489: The factories were prone to explode and, above all else, the burning speed of straight guncotton was always too high. It was not until 1884 that Paul Vieille tamed guncotton into a successful progressive smokeless gunpowder called Poudre B . Later on, in 1891, James Dewar and Frederick Augustus Abel also managed to transform gelatinized guncotton into a safe mixture, called cordite because it could be extruded into long thin cords before being dried. In 1990 an asteroid

9960-420: The form CdCl (aq) in oxic waters or CdS(s) in a reduced environment. Thus, higher concentrations of Cd in marine sediments may indicate low redox potential conditions in the past. For copper(II), a prevalent form is CuCl(aq) within oxic environments and CuS(s) and Cu 2 S within reduced environments. The reduced seawater environment leads to two possible oxidation states of copper, Cu(I) and Cu(II). Molybdenum

10080-420: The formation of a surface layer of sodium oxide or sodium superoxide . Though metallic sodium has some important uses, the major applications for sodium use compounds; millions of tons of sodium chloride , hydroxide , and carbonate are produced annually. Sodium chloride is extensively used for anti-icing and de-icing and as a preservative; examples of the uses of sodium bicarbonate include baking, as

10200-417: The forward reaction is enhanced if the humidity of the air is less than 100% or the water vapor is moved by a wind. Kinetic fractionation generally is enhanced compared to equilibrium fractionation and depends on factors such as reaction rate, reaction pathway and bond energy. Since lighter isotopes generally have weaker bonds, they tend to react faster and enrich the reaction products. Biological fractionation

10320-480: The heavier isotopes. For two phases A and B, the effect can be represented by the factor In the liquid-vapor phase transition for water, a l-v at 20 degrees Celsius is 1.0098 for O and 1.084 for H. In general, fractionation is greater at lower temperatures. At 0 °C, the factors are 1.0117 and 1.111. When there is no equilibrium between phases or chemical compounds, kinetic fractionation can occur. For example, at interfaces between liquid water and air,

10440-505: The largest two elements by fraction of total mass are hydrogen (74.9%) and helium (23.8%), with all the remaining elements contributing just 1.3%. There is a general trend of exponential decrease in abundance with increasing atomic number, although elements with even atomic number are more common than their odd-numbered neighbors (the Oddo–Harkins rule ). Compared to the overall trend, lithium , boron and beryllium are depleted and iron

10560-456: The lime forms lime feldspar. Magnesium carbonate and iron oxides with silica crystallize as olivine or enstatite , or with alumina and lime form the complex ferromagnesian silicates of which the pyroxenes , amphiboles , and biotites are the chief. Any excess of silica above what is required to neutralize the bases will separate out as quartz ; excess of alumina crystallizes as corundum . These must be regarded only as general tendencies. It

10680-417: The lower reactivity of complexed metals compared to the same concentration of free metal is that the chelation tends to stabilize metals in the aqueous solution instead of in solids. Concentrations of the trace metals cadmium , copper , molybdenum , manganese , rhenium , uranium and vanadium in sediments record the redox history of the oceans. Within aquatic environments, cadmium(II) can either be in

10800-546: The molecular state. Estimates also depend on models for the formation of the planets. Condensation of the presolar nebula would result in a gaseous planet with the same composition as the Sun, but the planets could also have formed when a solid core captured nebular gas. In current models, the four giant planets have cores of rock and ice that are roughly the same size, but the proportion of hydrogen and helium decreases from about 300 Earth masses in Jupiter to 75 in Saturn and just

10920-407: The most refractory group, uranium is used; iron for the second; the ratios of potassium and thallium to uranium for the next two; and the molar ratio FeO/(FeO+ MgO ) for the last. Using thermal and seismic models along with heat flow and density, Fe can be constrained to within 10 percent on Earth, Venus, and Mercury. U can be constrained within about 30% on Earth, but its abundance on other planets

11040-466: The need for large quantities of sodium. A related process based on the reduction of sodium hydroxide was developed in 1886. Sodium is now produced commercially through the electrolysis of molten sodium chloride (common salt), based on a process patented in 1924. This is done in a Downs cell in which the NaCl is mixed with calcium chloride to lower the melting point below 700 °C. As calcium

11160-451: The new compound. Ordinary black gunpowder , which had reigned supreme in the battlefield for the past 500 years, exploded into thick smoke, blackening the gunners, fouling cannons and small arms, and obscuring the battlefield. Nitrocellulose was perceived as a possible "smokeless powder" and a propellant for artillery shells thus it received the name of guncotton . Attempts to manufacture guncotton for military use failed at first because

11280-472: The ocean floor, sandstone on the edge of the continent, and dissolved minerals in ocean waters. Metamorphism and anatexis (partial melting of crustal rocks) can mix these elements together again. In the ocean, biological organisms can cause chemical differentiation, while dissolution of the organisms and their wastes can mix the materials again. A major source of differentiation is fractionation , an unequal distribution of elements and isotopes. This can be

11400-511: The ocean. Christian Friedrich Sch%C3%B6nbein Christian Friedrich Schönbein HFRSE (18 October 1799 – 29 August 1868) was a German-Swiss chemist who is best known for inventing the fuel cell (1838) at the same time as William Robert Grove and his discoveries of guncotton and ozone . He also created the concept of geochemistry in 1838. Schönbein (Schoenbein) related to Michael Schoenbein

11520-461: The percentage of silica and alkali's, the greater is the prevalence of plagioclase feldspar as contracted with soda or potash feldspar. Earth's crust is composed of 90% silicate minerals and their abundance in the Earth is as follows: plagioclase feldspar (39%), alkali feldspar (12%), quartz (12%), pyroxene (11%), amphiboles (5%), micas (5%), clay minerals (5%); the remaining silicate minerals make up another 3% of Earth's crust. Only 8% of

11640-458: The planets can only be used to detect vibrations of molecules, which are in the infrared frequency range. This constrains the abundances of the elements H, C and N. Two other elements are detected: phosphorus in the gas phosphine (PH 3 ) and germanium in germane (GeH 4 ). The helium atom has vibrations in the ultraviolet range, which is strongly absorbed by the atmospheres of the outer planets and Earth. Thus, despite its abundance, helium

11760-519: The planets, while the internal distribution of elements is constrained by their moments of inertia. The planets condensed from the solar nebula, and much of the details of their composition are determined by fractionation as they cooled. The phases that condense fall into five groups. First to condense are materials rich in refractory elements such as Ca and Al. These are followed by nickel and iron, then magnesium silicates . Below about 700 kelvins (700 K), FeS and volatile-rich metals and silicates form

11880-405: The plutonic representatives of the same magma, granite, and syenite contain biotite and hornblende far more commonly than augite. Those rocks that contain the most silica, and on crystallizing yield free quartz, form a group generally designated the "felsic" rocks. Those again that contain the least silica and most magnesia and iron, so that quartz is absent while olivine is usually abundant, form

12000-603: The position of elements in the periodic table . Based on position, the elements fall into the broad groups of alkali metals , alkaline earth metals , transition metals , semi-metals (also known as metalloids ), halogens , noble gases , lanthanides and actinides . Another useful classification scheme for geochemistry is the Goldschmidt classification , which places the elements into four main groups. Lithophiles combine easily with oxygen. These elements, which include Na , K , Si , Al , Ti , Mg and Ca , dominate in

12120-441: The positive charge counterbalanced by electrons as anions ; cryptands permit the isolation of these complexes as crystalline solids. Sodium forms complexes with crown ethers, cryptands and other ligands. For example, 15-crown-5 has a high affinity for sodium because the cavity size of 15-crown-5 is 1.7–2.2 Å, which is enough to fit the sodium ion (1.9 Å). Cryptands, like crown ethers and other ionophores , also have

12240-456: The pressure increases. By itself or with potassium , sodium is a desiccant ; it gives an intense blue coloration with benzophenone when the desiccate is dry. In organic synthesis , sodium is used in various reactions such as the Birch reduction , and the sodium fusion test is conducted to qualitatively analyse compounds. Sodium reacts with alcohols and gives alkoxides , and when sodium

12360-426: The rate of removal of salt should be proportional to its concentration. For a given component C , if the input to a reservoir is a constant a and the output is kC for some constant k , then the mass balance equation is This expresses the fact that any change in mass must be balanced by changes in the input or output. On a time scale of t = 1/k , the system approaches a steady state in which C =

12480-701: The reduced form UO 2 (s). Vanadium is in several forms in oxidation state V(V); HVO 4 and H 2 VO 4 . Its reduced forms can include VO 2 , VO(OH) 3 , and V(OH) 3 . These relative dominance of these species depends on pH . In the water column of the ocean or deep lakes, vertical profiles of dissolved trace metals are characterized as following conservative–type , nutrient–type , or scavenged–type distributions. Across these three distributions, trace metals have different residence times and are used to varying extents by planktonic microorganisms. Trace metals with conservative-type distributions have high concentrations relative to their biological use. One example of

12600-469: The result of chemical reactions, phase changes , kinetic effects, or radioactivity . On the largest scale, planetary differentiation is a physical and chemical separation of a planet into chemically distinct regions. For example, the terrestrial planets formed iron-rich cores and silicate-rich mantles and crusts. In the Earth's mantle, the primary source of chemical differentiation is partial melting , particularly near mid-ocean ridges. This can occur when

12720-647: The science and is still adopted as the basis on which more minute subdivisions are erected. The subdivisions are by no means of equal value. The syenites, for example, and the peridotites, are far less important than the granites, diorites, and gabbros. Moreover, the effusive andesites do not always correspond to the plutonic diorites but partly also to the gabbros. As the different kinds of rock, regarded as aggregates of minerals, pass gradually into one another, transitional types are very common and are often so important as to receive special names. The quartz-syenites and nordmarkites may be interposed between granite and syenite,

12840-418: The solar system is similar to that of many other stars, and aside from small anomalies it can be assumed to have formed from a solar nebula that had a uniform composition, and the composition of the Sun 's photosphere is similar to that of the rest of the Solar System. The composition of the photosphere is determined by fitting the absorption lines in its spectrum to models of the Sun's atmosphere. By far

12960-493: The solid is heterogeneous or a solid solution , and part of the melt is separated from the solid. The process is known as equilibrium or batch melting if the solid and melt remain in equilibrium until the moment that the melt is removed, and fractional or Rayleigh melting if it is removed continuously. Isotopic fractionation can have mass-dependent and mass-independent forms. Molecules with heavier isotopes have lower ground state energies and are therefore more stable. As

13080-473: The structures of crystals. In the 1920s and 1930s, Victor Goldschmidt and associates at the University of Oslo applied these methods to many common minerals and formulated a set of rules for how elements are grouped. Goldschmidt published this work in the series Geochemische Verteilungsgesetze der Elemente [Geochemical Laws of the Distribution of Elements]. The research of Manfred Schidlowski from

13200-507: The surface, e.g., hypersthene, orthoclase, quartz. There are some curious instances of rocks having the same chemical composition, but consisting of entirely different minerals, e.g., the hornblendite of Gran, in Norway, which contains only hornblende, has the same composition as some of the camptonites of the same locality that contain feldspar and hornblende of a different variety. In this connection, we may repeat what has been said above about

13320-419: The system is always close to a steady-state and the lowest order expansion of the mass balance equation will lead to a linear equation like Equation ( 1 ). In most systems, one or both of the input and output depend on C , resulting in feedback that tends to maintain the steady-state. If an external forcing perturbs the system, it will return to the steady-state on a time scale of 1/ k . The composition of

13440-531: The tonalites and adamellites between granite and diorite, the monzonites between syenite and diorite, norites and hyperites between diorite and gabbro, and so on. Trace metals readily form complexes with major ions in the ocean, including hydroxide , carbonate , and chloride and their chemical speciation changes depending on whether the environment is oxidized or reduced . Benjamin (2002) defines complexes of metals with more than one type of ligand , other than water, as mixed-ligand-complexes. In some cases,

13560-445: The unstable isotopes do not occur in nature. In geochemistry, stable isotopes are used to trace chemical pathways and reactions, while radioactive isotopes are primarily used to date samples. The chemical behavior of an atom – its affinity for other elements and the type of bonds it forms – is determined by the arrangement of electrons in orbitals , particularly the outermost ( valence ) electrons. These arrangements are reflected in

13680-476: The valve stems are partially filled with sodium and work as a heat pipe to cool the valves. In humans, sodium is an essential mineral that regulates blood volume, blood pressure, osmotic equilibrium and pH . The minimum physiological requirement for sodium is estimated to range from about 120 milligrams per day in newborns to 500 milligrams per day over the age of 10. Sodium chloride , also known as edible salt or table salt (chemical formula NaCl ),

13800-466: Was born at Metzingen in the Duchy of Württemberg . Around the age of 13 he was apprenticed to a chemical and pharmaceutical firm at Böblingen . Through his own efforts, he acquired sufficient scientific skills and knowledge to ask for, and receive, an examination by the professor of chemistry at Tübingen . Schönbein passed the exam and, after a series of moves and university studies, eventually acquired

13920-519: Was first produced commercially in the late nineteenth century by carbothermal reduction of sodium carbonate at 1100 °C, as the first step of the Deville process for the production of aluminium: The high demand for aluminium created the need for the production of sodium. The introduction of the Hall–Héroult process for the production of aluminium by electrolysing a molten salt bath ended

14040-479: Was investigated and compared to terrestrial rocks as early as 1850. In 1901, Oliver C. Farrington hypothesised that, although there were differences, the relative abundances should still be the same. This was the beginnings of the field of cosmochemistry and has contributed much of what we know about the formation of the Earth and the Solar System. In the early 20th century, Max von Laue and William L. Bragg showed that X-ray scattering could be used to determine

14160-406: Was named after him. Sodium Sodium is a chemical element ; it has symbol   Na (from Neo-Latin natrium ) and atomic number  11. It is a soft, silvery-white, highly reactive metal . Sodium is an alkali metal , being in group 1 of the periodic table. Its only stable isotope is Na. The free metal does not occur in nature and must be prepared from compounds. Sodium

14280-529: Was only detected once spacecraft were sent to the outer planets, and then only indirectly through collision-induced absorption in hydrogen molecules. Further information on Jupiter was obtained from the Galileo probe when it was sent into the atmosphere in 1995; and the final mission of the Cassini probe in 2017 was to enter the atmosphere of Saturn. In the atmosphere of Jupiter, He was found to be depleted by

14400-554: Was the making of tetraethyllead and titanium metal; because of the move away from TEL and new titanium production methods, the production of sodium declined after 1970. Sodium is also used as an alloying metal, an anti-scaling agent , and as a reducing agent for metals when other materials are ineffective. Note the free element is not used as a scaling agent, ions in the water are exchanged for sodium ions. Sodium plasma ("vapor") lamps are often used for street lighting in cities, shedding light that ranges from yellow-orange to peach as

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