Általános Kémiához ábrák, etc.2006. ősz

2004. őszi tételsor az ElmKém web-oldalán:

www.chem.elte.hu/departments/elmkem/fg/oktatas/altkem(40 + tétel; főbb fejezetek:)

AlapfogalmakA gázhalmazállapotA reakciók energetikája (termokémia)A termodinamika alapjai, a folyamatok iránya, egyensúlyHalmazállapotok és fizikai tulajdonságokElektrokémiaReakciókinetikaAz anyag atomi - molekuláris szerkezete.Atomok elektronszerkezete és a periódusos rendszerA kémiai kötés

A kémia felosztása különböző lehetEgy könyvkiadó: WileyEurope > Chemistry

 Browse Chemistry subjects

Analytical Chemistry Biochemistry Chemical Engineering Computational Chemistry & Molecular Modeling Electrochemistry Environmental Chemistry General Chemistry 

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Kémia mindenhol

TOP 50 CHEMICALS: Rank Billions of lb1995 1994 1995 19941 1 Sulfuric acid 95.36 89.632 2 Nitrogen 68.04 63.913 3 Oxygen 53.48 50.084 4 Ethylene 46.97 44.605 5 Lime(b) 41.23 38.376 6 Ammonia 35.60 34.517 7 Phosphoric acid 26.19 25.588 8 Sodium hydroxide 26.19 25.119 10 Propylene 25.69 23.9410 9 Chlorine 25.09 24.3711 11 Sodium carbonate(c) 22.28 20.5612 18 Methyl tert-butyl ether 17.62 13.6113 14 Ethylene dichloride 17.26 16.7614 12 Nitric acid 17.24 17.2215 13 Ammonium nitrate(d) 15.99 17.0316 16 Benzene 15.97 15.27

22 20 Carbon dioxide(f) 10.89 11.80

27 26 Hydrochloric acid 7.33 7.47

33 33 Acetic acid 4.68 3.98

42 42 Titanium dioxide 2.77 2.7643 43 Acetone 2.76 2.66

50 49 Bisphenol A 1.62 1.70

Top 50 Chemical Companies in 1999Rank Company Total sales Chemical sales Chemical operating profits

Rank Company Total sales Chemical sales Chem. Oper. profits  1999   1998 1999  ($ M) 1999  ($ M) % of 1999  ($ M) %

total1 1 BASF (Germany) 34,689.4 31,250.3 90.1% 1,350.9 4.32 2 DuPont (U.S.) 29,740.0 27,688 .0 93.1 2,961.0 10.73 3 Bayer (Germany) 29,106.7 20,192.5 69.4 3,024.7 15.04 4 Dow Chemical (U.S.) 18,929.0 18,600.0 98.3 2,732.0 14.75 8 Exxon Mobil (U.S.)b 185,527.0 13,777.0 7.4 1,354.0 9.86 6 ICI (U.K.) 13,671.5 13,671.5 100.0 923.9 6.87 5 Shell (U.K./Netherlands) 149,706.0 12,886.0 8.6 885.0 6.98 19 Akzo Nobel (Netherlands) 15,375.9 12,323.5 80.1 819.3 6.69 35 Degussa-Hüls (Germany)c 13,157.7 10,085.8 76.7 544.6 5.410 11 BP Amoco (U.K.) 101,180.0 9,392.0 9.3 1,100.0 11.711 28 Total (France)c 42,069.0 9,343.6 22.2 643.5 6.912 10 Elf Aquitaine (France) 37,872.8 9,272.2 24.5 540.2 5.813 13 Sumimoto Chemical (Japan) 8,342.9 8,136.5 97.5 588.9 7.2

16 18 Henkel (Germany) 12,104.0 7,324.6 60.5 604.1 8.2 

Nemzeti jövedelmekhez hasonlítva:

Comparative economic indicators, 2000Hungary Slovenia Slovakia

GDP (US$ bn) 45.6 18.1 19.2GDP per head (US$ at PPP) 9,035 14,250 8,718

March 12, 2002 : The survey, published in a recent issue of the Society's publication, Chemical & Engineering News (C & EN), ranks the global top 50 by their chemical sales. It also charts their total sales, chemical operating profits and capital spending

The Consumer Law Page: Articles: http://consumerlawpage.com/article/household-chemicals.shtml

TOP "10" HAZARDOUS HOUSEHOLD CHEMICALSBy Richard Alexander

AIR FRESHENERS: Most air fresheners interfere with your ability to smell by coating your nasal passages with an oil film, or by releasing a nerve deadening agent. Known toxic chemicals found in an air freshener: Formaldehyde: Highly toxic, known carcinogen. Phenol: When phenol touches your skin it can cause it to swell, burn, peel, and break out in hives. Can cause cold sweats,convulsions, circulatory collapse, coma and even death.

AMMONIA: It is a very volatile chemical, it is very damaging to your eyes, respiratory tract and skin.

BLEACH: It is a strong corrosive. It will irritate or burn the skin, eyes and respiratory tract. It may cause pulmonary edema or vomiting and coma if ingested. WARNING: never mix bleach with ammonia it may cause fumes which can be DEADLY.

DISHWASHER DETERGENTS: Most products contain chlorine in a dry form that is highly concentrated.# 1 cause of child poisonings, according to poison control centers.

DRAIN CLEANER: Most drain cleaners contain lye, hydrochloric acid or trichloroethane. Lye: Caustic, burns skin and eyes, if ingested will damage esophagus and stomach. Hydrochloric acid: Corrosive, eye and skin irritant, damages kidneys, liver and digestive tract. Trichloroethane: Eye and skin irritant, nervous system depressant; damages liver and kidneys.

contnd,.

FURNITURE POLISH: Petroleum Distillates: Highly flammable, can cause skin and lung cancer. Phenol: (see Air fresheners, Phenol.) Nitrobenzene: Easily absorbed through the skin, extremely toxic.

MOLD AND MILDEW CLEANERS: Chemicals contained are: Sodium hypochlorite: Corrosive, irritates or burns skin and eyes, causes fluid in the lungs which can lead to coma or death. Formaldehyde: Highly toxic, known carcinogen. Irritant to eyes, nose, throat, and skin. May cause nausea, headaches, nosebleeds, dizziness, memory loss and shortness of breath.

OVEN CLEANER: Sodium Hydroxide (Lye): Caustic, strong irritant, burns to both skin and eyes. Inhibits reflexes, will cause severe tissue damage if swallowed.

ANTIBACTERIAL CLEANERS: may contain: Triclosan: Absorption through the skin can be tied to liver damage.

LAUNDRY ROOM PRODUCTS: Sodium or calcium hypocrite: Highly corrosive, irritates or burns skin, eyes or respiratory tract. Linear alkylate sulfonate: Absorbed through the skin. Known liver damaging agent. Sodium Tripolyphosphate: Irritates skin and mucous membranes, causes vomiting. Easily absorbed through the skin from clothes.

TOILET BOWL CLEANERS: Hydrochloric acid: Highly corrosive, irritant to both skin and eyes. Damages kidneys and liver. Hypochlorite Bleach: Corrosive, irritates or burns eyes, skin and respiratory tract. May cause pulmonary edema, vomiting or coma if ingested. Contact with other chemicals may cause chlorine fumes which may be fatal

September 6, 2004Vol. 82, Iss. 36

VÁLOGATÁSOK KURRENS EREDMÉNYEKBŐL:

INHIBITORS TARGET KEY TB ENZYME Iminosugars may provide leads for new class of tuberculosis drugs

Scientists in England have designed and synthesized the first inhibitors of an enzyme that is essential for the survival of the tuberculosis bacterium [Org. Biomol. Chem., 2, 2418 (2004)]. The compounds might lead to better treatments for TB, which annually infects 8 million to 10 million people and kills 2 million to 3 million. e and kills 2 million to 3 million.

SCIENCE & TECHNOLOGY

 RDX LINKS RUSSIAN CRASHES

Powerful explosive found in the debris of two planes that crashed

 

 

 

Traces of RDX, a common military explosive that is also known as hexogen or cyclonite, were found at the crash sites of two Russian planes that went down within minutes of each other on Aug. 24, Russian authorities report. RDX was also used in a suicide bombing at a Moscow metro station on Aug. 31, news reports say. "RDX is a very powerful explosive," says Jimmie C. Oxley, a professor of chemistry at the University of Rhode Island. "A terrorist wouldn't need to conceal very much." RDX has an explosive power considerably greater than that of TNT, is chemically stable, and is more susceptible than TNT to shock detonation.

"Molekuláris giroszkóp"

COMPOSITE MATERIALS Custom blending of materials with distinct characteristics leads to advanced composites with tailor-made properties

IT'S A BIRD, IT'S A PLANE ... Advanced composite materials in the V-22 Osprey's tilt-rotor system play a key role in enabling the sophisticated plane to take off and land on aircraft carriers like a helicopter and fly like a turboprop airplane.

SHEET MOLDING Sheets of a composite molding material can be prepared by feeding glass or carbon fibers (chopped or intact) and a polymer-based resin (orange trough) between a pair of plastic films

Gyönyörűszép Molekulák

One example, reported by Bryan W. Eichhorn's group at the University of Maryland, is the [As@Ni12@As20]3–

ion. This cluster consists of an As20 pentagonal dodecahedron that encapsulates a Ni12 icosahedron, which contains an

arsenic atom at its center. The As20 cage is related to the smallest fullerene, C20 C&EN May 5, 2003

Source: C&EN/ April 14, 2003 

MOLECULAR DESIGN 

ION RECOGNITION

System exploits weak interactions to attract anion to cation in capsule

A new approach to anion recognition that uses electrostatic and hydrogen-bonding interactions has been developed by chemists

at the University of Missouri, Columbia. 

"For the first time, we have utilized a single molecule to completely encapsulate an ion pair in polar media," chemistry professor Jerry L. Atwood tells C&EN. "We envision that resins incorporating these capsules could be used in anion sensing in

environmental applications."Atwood and postdoc Agnieszka Szumna embedded a

tetramethylammonium cation in the pocket of a resorcin[4]arene molecule functionalized with bulky amide substituents. The

complex selectively binds to a chloride anion in solvents such as methanol [Chem. Comm., 2003, 940].

  

In infants, EPO is produced mostly in the liver, but the kidneys become the primary site of EPO synthesis shortly after birth. EPO production is stimulated by reduced oxygen content in arterial blood in the kidneys. Circulating EPO binds to receptors on the surface of erythroid progenitor cells that in turn mature into red blood cells.….. contnd

Understanding the function of endogenous hormones and putting them to good use to treat diseases has been one of the great accomplishments of modern medicine. One natural hormone that has turned out to be a blockbuster drug--but not without some controversy--is erythropoietin (EPO).

Ezt is tudjuk …… EPO

EPO is a glycoprotein (protein-sugar conjugate) that serves as the primary regulator of red blood cells (erythrocytes) in mammals. It stimulates bone marrow stem cells to differentiate into red blood cells and controls hemoglobin synthesis and red blood cell concentration. Human EPO is a 30,400-dalton molecule containing 165 amino acids and four carbohydrate chains that incorporate sialic acid residues. There are several forms of EPO, designated by Greek letters, that differ only in the carbohydrate content.

Human EPO was first isolated and later purified from urine in the 1970s. Interest in developing clinical uses for EPO led to the discovery of the gene encoding EPO, and several groups devised recombinant DNA methods to produce EPO by the mid-1980s.

Recombinant EPO quickly made it to market to treat anemia resulting from a host of conditions, primarily kidney failure, HIV infection in patients treated with AZT, and cancer chemotherapy. Doses of EPO are given by injection one or more times per week to maintain a normal hematocrit level, the ratio of red blood cell volume to total blood volume. Generally, EPO might be prescribed for any condition where blood oxygen levels are depressed and to help eliminate the potential need for blood transfusions.

……

Enzyme immunoassays can provide a measure of serum EPO levels, but the tests can't determine if the EPO is natural or produced recombinantly and injected by unscrupulous athletes. The World Anti-Doping Agency has now developed combination urine and blood tests that can detect EPO abuse by athlet.

Robert Boyle (1627–1691) was born at Lismore Castle, Munster, Ireland, the fourteenth child of the Earl of Cork. As a young man of means, he was tutored at home and on the Continent. He spent the later years of the English Civil Wars at Oxford, reading and experimenting with his assistants and colleagues. This group was committed to the New Philosophy, which valued observation and experiment at least as much as logical thinking in formulating accurate scientific understanding. At the time of the restoration of the British monarchy in 1660, Boyle played a key role in founding the Royal Society to nurture this new view of science.

Although Boyle's chief scientific interest was chemistry, his first published scientific work, New Experiments Physico-Mechanicall, Touching the Spring of the Air and its Effects (1660), concerned the physical nature of air, as displayed in a brilliant series of experiments in which he used an air pump to create a vacuum. The second edition of this work, published in 1662, delineated the quantitative relationship that Boyle derived from experimental values, later known as "Boyle's law": that the volume of a gas varies inversely with pressure.

Robert Boyle at the age of thirty-seven, with his air pump in the background. François Diodati reengraved this image from an engraving by William Faithorne, Opera varia (1680).

Courtesy Edgar Fahs Smith Memorial Collection, Department of Special Collections, University of

Pennsylvania Library.

Boyle was an advocate of corpuscularism, a form of atomism that was slowly displacing Aristotelian and Paracelsian views of the world. Instead of defining physical reality and analyzing change in terms of Aristotelian substance and form and the classical four elements of earth, air, fire, and water—or the three Paracelsian elements of salt, sulfur, and mercury—corpuscularism discussed reality and change in terms of particles and their motion. Boyle believed that chemical experiments could demonstrate the truth of the corpuscularian philosophy. In this context he defined the term element in Sceptical Chymist (1661): " . . . certain primitive and simple, or perfectly unmingled bodies; which not being made of any other bodies, or of one another, are the ingredients of which all those called perfectly mixt bodies are immediately compounded, and into which they are ultimately resolved."

Robert Boyle: The Skeptical Chemist, 1661 (!)  "Én megpróbáltam a kémiát más szempontok szerint művelni, nem úgy, ahogy az eddigi kémikusok tették, hanem ahogy egy tudóshoz illik." .... "Bár viselnék az emberek inkább a tudományok előrehaladását szívükön, mint önző érdeküket, akkor könnyen belátnák, hogy nagyobb szolgálatot tennének a világnak, ha minden erejüket kísérletek végzésére és megfigyelések gyűjtésére fordítanák, ahelyett hogy kísérleti alapozás nélküli elméleteket állítanának fel. "

The Burning lenses

Calcination of a piece of metal with the burning lenses

Jövőre:

In 1811 Avogadro hypothesized that equal volumes of gases at the same temperature and pressure contain equal numbers of molecules. From this hypothesis it followed that relative molecular weights of any two gases are the same as the ratio of the densities of the two gases under the same conditions of temperature and pressure. Avogadro also astutely reasoned that simple gases were not formed of solitary atoms but were instead compound molecules of two or more atoms. (Avogadro did not actually use the word atom; at the time the words atom and molecule were used almost interchangeably. He talked about three kinds of "molecules," including an "elementary molecule"—what we would call an atom.) Thus Avogadro was able to overcome the difficulty that Dalton and others had encountered when Gay-Lussac reported that above 100oC the volume of water vapor was twice the volume of the oxygen used to form it. According to Avogadro, the molecule of oxygen had split into two atoms in the course of forming water vapor. Curiously, Avogadro's hypothesis was neglected for half a century after it was first published. Many reasons for this neglect have been cited, including some theoretical problems, such as Jöns Jakob Berzelius's "dualism," which asserted that compounds are held together by the attraction of positive and negative electrical charges, making it inconceivable that a molecule composed of two electrically similar atoms—as in oxygen—could exist. In addition, Avogadro was not part of an active community of chemists: the Italy of his day was far from the centers of chemistry in France, Germany, England, and Sweden, where Berzelius was based. Avogadro was a native of Turin, where his father, Count Filippo Avogadro, was a lawyer and government leader in the Piedmont (Italy was then still divided into independent countries). Avogadro succeeded to his father's title, earned degrees in law, and began to practice as an ecclesiastical lawyer. After obtaining his formal degrees, he took private lessons in mathematics and sciences, including chemistry. For much of his career as a chemist he held the chair of physical chemistry at the University of Turin.

Amedeo Avogadro.

Joseph Louis Gay-Lussac’s law of combining volumes (1808) (when two gases react, the volumes of the reactants and products—if gases—are in whole number ratios) tended to support Dalton’s atomic theory. Dalton did not in fact accept Gay-Lussac's work, but the Italian chemist Amedeo Avogadro (1776–1856) saw it as the key to a better understanding of molecular constituency.

Avogadro EREDETI CIKKEBOL! : http://web.lemoyne.edu/~giunta/avogadro.htmlA TELJES SZOVEGET FILE-BAN ELTETTEM: avogadro-original

Essay on a Manner of Determining the Relative Masses of the Elementary Molecules of Bodies, and the Proportions in Which They Enter into These CompoundsJournal de Physique 73, 58-76 (1811) [Alembic Club Reprint No. 4] I.M. Gay-Lussac has shown in an interesting Memoir (Mémoires de la Société d'Arcueil, Tome II.) that gases always unite in a very simple proportion by volume, and that when the result of the union is a gas, its volume also is very simply related to those of its components. But the quantitative proportions of substances in compounds seem only to depend on the relative number of molecules which combine, and on the number of composite molecules which result. It must then be admitted that very simple relations also exist between the volumes of gaseous substances and the numbers of simple or compound molecules which form them. Kiemeles FG: The first hypothesis to present itself in this connection, and apparently even the only admissible one, is the supposition that the number of integral molecules in any gases is always the same for equal volumes, or always proportional to the volumes . Indeed, if we were to suppose that the number of molecules contained in a given volume were different for different gases, it would scarcely be possible to conceive that the law regulating the distance of molecules could give in all cases relations as simple as those which the facts just detailed compel us to acknowledge between the volume and the number of molecules. On the other hand, it is very well conceivable that the molecules of gases being at such a distance that their mutual attraction cannot be exercised, their varying attraction for caloric may be limited to condensing the atmosphere formed by this fluid having any greater extent in the one case than in the other, and, consequently, without the distance between the molecules varying; or, in other words, without the number of molecules contained in a given volume being different. Dalton, it is true, has proposed a hypothesis directly opposed to this, namely that the quantity of caloric is always the same for the molecules of all bodies whatsoever in the gaseous state, and that the greater or less attraction for caloric only results in producing a greater or less condensation of this quantity around the molecules, and thus varying the distance between the molecules themselves. But in our present ignorance of the manner in which this attraction of the molecules for caloric is exerted, there is nothing to decide us à priori in favour of the one of these hypotheses rather than the other; and we should rather be inclined to adopt a neutral hypothesis, which would make the distance between the molecules and the quantities of caloric vary according to unknown laws, were it not that the hypothesis we have just proposed is based on that simplicity of relation between the volumes of gases on combination, which would appear to be otherwise inexplicable.

Maxwell, around 1875, describing atoms:  

"foundation stones of the material universe ... unbroken and unworn. They continue to this day as they were createdperfect in number and measure and weigth." (Scientific American, Aug. 1997, p. 73.)

1s állapot

2pz állapot

2s állapot

3s állapot

Elektron-sűrűséga H-atom-ban

Force Between Parallel Wires

If the currents are parallel, the force is attractive.

If the currents are anti-parallel, the force is repulsive.

PROTOTYPE The mass of the international kilogram artifact in Paris may be changing.

REDEFINITION Ian Robinson, a fellow in electrical metrology at the U.K.'s National Physical Laboratory, uses the watt balance to determine values for the Planck constant. (NPL photographs: © Crown copyright 1999. Reproduced by permission of the Controller of HMSO and the Queen's Printer for Scotland)NPL PHOTO

Electronic Balancehttp://www.sensorsmag.com/articles/0602/27/pf_main.shtml

Jean-Christophe Emery, Mettler Toledo GmbH

The most accurate electronic balances are based on electromagnetic force restoration (EMFR), also called electromagnetic force compensation. ….., one or more levers, and an electromagnetic system that assumes the role of the weights in a two-pan scale balance. Equilibrium is maintained by a control system incorporating an optical position sensor.

                                                               .

When the coil’s force compensates the gravitational force exerted by an unknown mass, an optical sensor detects a stable predefined zero position that indicates a state of equilibrium. Changing the ratio of the levers allows forces smaller than 1 N to balance much bigger ones. Today it is common to have a system with one, two, or even three levers, depending on the load range.

U.S. National Chemistry Olympiad

1995 National Test

An open-ended mercury manometer is used to measure the pressure exerted by a trapped gas as shown in the figure. Atmospheric pressure is 749 mmHg. What is the pressure of the trapped

gas?

Higanyos manométer:

Egy mai kereskedelmi higanyos manométer (olasz cég hirdetése)http://www.imgc.to.cnr.it/english/aboutimgc/department/manometro.htm

The HG5 mercury manometerThe HG5 manometer is the primary standard of IMGC for the barometric pressure (100 Pa to 120 kPa) both in absolute and gauge mode. Designed and built at IMGC after long experimentation, it is based on the old principle of measurement used by Torricelli, that is to say the atmospheric pressure is weighted by a mercury column whose height is measured. HG5 is made by a glass U-tube, filled with mercury up to half height and immersed in a bath of termostated water, in which the temperature is maintained constant at 20 °C. The dimensions of the two columns of the U-tube are 1 m length , 60 mm internal diameter; the differential mercury displacement, (the column height) , from the initial equilibrium position, ( that is the “zero position”, with the same pressure in both columns), is detected through a “single beam” differential interferometer. 

Farm Toxins: Mercury Manometer Replacement"October 2, 2000 WPTZ NEWS CHANNEL 5 farms within the Vermont portion of the Lake Champlain Basin. Replacing mamometers will help prevent mercury pollution in the basin and help protect the health of humans and animals on dairy farms.

Manometers are used by farmers to measure the proper working pressure of milking systems. The Northwest Vermont Solid Waste Management District received $20,200 through the Lake Champlain Basin Program for this project. In partnership with the Vermont Department of Agriculture, 42 out of 84 known mercury manometers have been replaced with non-mercury manometers so far - at no cost to the farmers. Each manometer contains up to 1/2 pound of mercury. The mercury collected will be disposed by a certified mercury handler. .......

Bourdon-cső:

A szobai barométer aneroid b.

Pirani Gauges:

KIS NYOMÁSOK MÉRÉSEPirani-vákuummérőElv: a gáz hővezető képessége nyomásától fógg

In a Pirani gauge (see above), two filaments (platinum alloy in the best gauges), act as resistances in two arms of a Wheatstone bridge. The reference filament is immersed in a fixed-gas pressure, while the measurement filament is exposed to the system gas

Ionisations-Vakuummeter bestehen im allgemeinen aus drei Elektroden (Glühkathode, Anode und Ionenfänger). Sie arbeiten bei niedrigen Spannungen und ohne äußeres Magnetfeld. Die Glühkathode ist eine sehr ergiebige Elektronenquelle. Die Elektronen werden im elektrischen Feld (s. Abb. 4) beschleunigt und nehmen aus dem Feld genügend Energie auf, um das Gas, in dem sich das

Elektrodensystem befindet, zu ionisieren. Die gebildeten positiven Gasionen gelangen auf den bezüglich der Kathode negativen Ionenfänger und geben hier ihre Ladung ab. Der dadurch

entstehende Ionenstrom ist ein Maß für die Gasdichte und damit für den Gasdruck

Még érzékenyebb az Ionizációs Vákuummérő

Térfogatmérés

eudiométer

piknométer

Hőmérsékletmérés: a termoelektromos effektus (Seebeck, 1821!)

The Seebeck effect is the conversion of temperature differences directly into electricity.This effect was first discovered, accidentally, by the Estonian physicist Thomas Johann Seebeck in 1821, who found that a voltage existed between two ends of a metal bar when a temperature gradient ΔT existed in the bar.

The effect is that a voltage, the thermoelectric EMF, is created in the presence of a temperature difference between two different metals or semiconductors. This causes a continuous current to flow in the conductors if they form a complete loop. The voltage created is of the order of several microvolts per degree difference.

Fordítottja: Peltier-effektus; hűtőgép!

SA and SB are the Seebeck coefficients (also called

thermoelectric power or thermopower) of the metals A and B, and T1 and T2 are the temperatures of the two junctions. The

Seebeck coefficients are non-linear, and depend on the conductors' absolute temperature, material, and molecular structure. If the Seebeck coefficients are effectively constant for the measured temperature range, the above formula can be approximated as:

http://en.wikipedia.org/wiki/Peltier-Seebeck_effect

    

http://www.widdernet.de/saccharimeter.html

Saccharimeter, Brix Hydrometer The saccharimeter measures the percentage of sugar content in a liquid. The most common types  of saccharimeter are according to: Brix %, Mas % at 20 C / 68 F or previously acc. to weight - gew.%     Breweries used  to measure in Balling.A weight % or gew.% scale is based on 1 kilogram out of 100.  In case of a measurement of 50 Wt.%, 5o kilograms are pure sugar and the rest is water. In Brix or Mas it is the same and even in Balling in case of  20 C / 68 F !How to use: For using a saccharimeter you require a test jar to make an exact and easy reading! Before and after use clean the  saccharimeter and test jar with warm water and dry before use. The  saccharimeter should also be wiped dry with a linen cloth. After cleaning, the  saccharimeter should be held only from the thin part above the paper scale. The clean liquid is first poured into the test jar, leaving at least 2” / 5 cm from the rim free.  Close the test jar with a clean plastic foil and with the palm of the hand, shake 10 times! Be careful if acid or lye is in your  testing liquid ! The  saccharimeter is now dipped slowly into the liquid until it floats freely. The saccharimeter has to be free of bubbles! Do not let the  saccharimeter fall into the test jar! The reading is taken at eye level at the spot where the thin part or stem intersects the liquid, i.e. at the level of the liquid surface. Record the temperature of the liquid. Take care of the temperature of room, liquid and instrument is the same. Store  test jar, liquid, instrument about 4 hours in the same room you test!

Az areométer (hydrometer) a borászatbanSűrűségmérés

Sűrűségmérés Mohr-Westphal-mérleggel Mint ismeretes, Archimedes elve alapján a folyadékok sűrűsége meghatározható azáltal, hogy megmérjük egy üvegtest súlyveszteségét az illető folyadékban, majd 4C° hőmérsékletű vízbe mártva.

Amit a szerkezeti képlet nem fejez ki: OPTIKAI IZOMÉRIAhttp://en.wikipedia.org/wiki/Chirality_(chemistry)

The term non-superimposable distinguishes mirror images which are superposable, such as the letter "A" and its mirror image, from those that are not. The classic example of this are human hands. The left hand is a non-superposable mirror image of the right hand: No matter how the two hands are oriented relative to one another, one cannot line up all the major features of one hand with the other, whereas such an operation is trivial for a non-chiral mirror image (e.g., the letter "A").The two "hands" (enantiomers) of a chiral molecule are sometimes referred to as optical isomers. The two enantiomers of bromochlorofluoromethaneIt is the symmetry of a molecule (or any other object) that determines whether it is chiral or not. Kiemelés FG: Technically, a molecule is achiral (not chiral) if and only if it has an axis of improper rotation; that is, an n-fold rotation (rotation by 360°/n) followed by a reflection in the plane perpendicular to this axis which maps the molecule onto itself. (See chirality (mathematics).) A chiral molecule is not necessarily dissymmetric (completely devoid of symmetry) as it can have, for example, rotational symmetry. A simplified rule applies to tetrahedrally-bonded carbon, as shown in the illustration: if all four substituents are different, the molecule is chiral.

The term chiral is used to describe an object which is non-superimposable on its mirror image. In terms of chemistry, these objects are usually molecules and the study of chiral molecules and associated phenomena is a very active area.A molecule is chiral when it cannot be superimposed on its mirror image (see diagram) with the two mirror image forms referred to as enantiomers. A mixture of equal amounts of the two enantiomers is said to be a racemic mixture. Chirality is of interest because of its application to stereochemistry in inorganic chemistry, organic chemistry, physical chemistry and biochemistry. The study of chirality falls in the domain of stereochemistry.

A rule of thumb for determining the D/L isomeric form of an amino acid is the "CORN" rule. The groups:

COOH, R, NH2 and H (where R is an unnamed carbon

chain) . are arranged around the chiral center carbon atom. Sighting from the hydrogen atom, if these groups are arranged counter-clockwise around the carbon atom, then it is the D-form. If clockwise, it is the L-form.

A bűnös: tesztoszteroneAmit mérnek: két optikai izomer arányatesztoszterone-/epitesztoszteroneEpitestosterone, as its name suggests, is an epimer of testosterone-a stereoisomer that differs only in the configuration at one chiral center, which in this case is the hydroxyl group at C-17 of the steroid ring system.

C&EN, August 28, 2006 Volume 84, Number 35 pp. 43-45

MSU Gallery of Chemists' Photo-Portraits and Mini-BiographiesSvante August Arrhenius1859-1927  Portrait: 3Location - Floor: First - Zone: Room 138 - Wall: South - Sequence: 6Source: Chemical Heritage FoundationSponsor: Kris A. Berglund

This Swedish physical chemist is best known for his theory of electrolytic dissociation in aqueous solution, first presented for his doctorate thesis at the University of Uppsala when he was 24. The idea that oppositely charged ions resulting from dissociation of molecules could be present in the same solution initially met a hostile reception, but with support from Ostwald, van't Hoff and others the theory was gradually accepted. He is also known for the Arrhenius Equation k = A exp -E/RT, which describes the effect of temperature on reaction rates. He was instrumental in establishing physical chemistry as a separate discipline. A man of eclectic scientific interests, he later published papers on immunology, cosmology and geology. He was awarded the 1903 Nobel Prize in Chemistry. http://poohbah.cem.msu.edu/Portraits/PortraitsHH_Detail.asp?HH_LName=Arrhenius

“Kettős szubsztitúciós” reakció a szerves kémiában: 2005. évi kémiai Nobel-díj

                               

         

                              

          Charles Friedel, born in Strasbourg on March 12, 1832, was not only a chemist, but also a mineralogist. Friedel studied at the Sorbonne in Paris. He died in 1899.James Mason Crafts, born in 1839, studied chemistry first in Germany and then in France after graduating in 1858 from Harvard. Crafts died in 1917 after spending his career divided between the U.S. and Sorbonne. Friedel and Crafts collaborated with one another from 1874-1891. In 1877 they discovered what is now known as the Friedel-Crafts reaction: the alkylation karbokation or acylation of an aromatic compound catalyzed by a Lewis acid.

Friedel

Lewis savak fontos alkalmazása: Friedel-Crafts katalizátorok, pl. AlCl3

Friedel jegyzőkönyve

Alkilezés

Acilezés

RCl + AlCl3 R+ (karbokation!)+ AlCl4-

Crafts

Sav-bázis elméletekhez: Szupersavak

Press Release: The 1994 Nobel Prize in Chemistry 12 October 1994

The Royal Swedish Academy of Sciences has decided to award the 1994 Nobel Prize in Chemistry to

Professor George A. Olah, University of Southern California, USA for his contributions to carbocation chemistry.

Oláh György, 1994-es Nobel-díj

http://www.psc.edu/science/2000/klein/getting_jump_on_superacids.html

superacids as chemical superheroes. These fascinating compounds have, since the 1960s,

become an essential tool of the chemical industry. Their powerful ability to react with and break

down raw petroleum brings us such products as high-strength plastics and lead-free, high-octane gas. Exotic processes like coal gasification are unthinkable without superacids.The strongest superacid is antimony pentafluoride in hydrogen fluoride (SbF5/HF), and experiments

have shown that these solutions conduct electricity better than can be accounted for by ionic diffusion,

SbF5 - Lewis-sav; SbF5/HF szupersav; mechanizmus bizonytalan;

SbF5 + HF SbF6- + H+ nyilván fontos,

A fő kérdés az lehet, hogy a proton milyen formában van jelen? (ionosnál jobb vezetés, HF..HF... láncon fut végig a protoncsere)

Superacids are so strong that they can protonate such extremely weak bases as the alkanes, as was shown by Olah and independently by H. Hogeveen. Thus, pentacoordinated carbonium ions have been obtained from methane higher alkanes and various cycloalkanes. Methane

gives the methionium ion CH5+

Understanding the Infrared Spectrum of Bare CH5+

Oskar Asvany,1* Padma Kumar P,2* Britta Redlich,3 Ilka Hegemann,2 Stephan Schlemmer,1,4 Dominik Marx2

Science, Vol 309, Issue 5738, 1219-1222, 19 August 2005

Call movie :

ProgramFiles/ch5+_8000