CHEMISTRY GLOSSARY
mass spectrometry → masena spectrometrija
Mass spectrometry is an analytical technique in which ions are separated according to the mass/charge (m/e) ratio and detected by a suitable detector.
In a mass spectrometer a sample is ionised and the positive ions produced are accelerated into a high-vacuum region containing electric and magnetic fields. These fields deflect and focus the ions onto a detector. A mass spectrum is thus obtained, consisting of a series of peaks of variable intensity to which m/e values can be assigned. Different molecules can be identified by their characteristic pattern of lines.
mass-energy equivalence → ekvivalencija mase i energije
In the special theory of relativity Einstein demonstrated that neither mass nor energy were conserved separately, but that they could be traded one for the other and only the total "mass-energy" was conserved. The relationship between the mass and the energy is contained in what is probably the most famous equation in science,
Where m is the mass of the object and c is the velocity of light. Cockcroft and Walton (1932) are routinely credited with the first experimental verification of mass-energy equivalence.
melting point → talište
Melting point is the temperature at which a solid becomes a liquid at normal atmospheric pressure.
A more specific definition of melting point (or freezing point) is the temperature at which the solid and liquid phases of a substance are in equilibrium at a specified pressure (normally taken to be atmospheric unless stated otherwise). A pure substance under standard condition of pressure has a single reproducible melting point. The terms melting point and freezing point are often used interchangeably, depending on whether the substance is being heated or cooled.
Zimmermann-Reinhardt’s reagent → Zimmermann-Reinhardtov reagens
Zimmermann-Reinhardt’s reagent is a mixture of manganese(II) sulphate, sulphuric acid and phosphorus acid. It is used for preventing oxidation of chloride ion while titrating iron(II) ion with permanganate solution.
mercury → živa
Mercury has been known since ancient times. The origin of the name comes from the Latin word hydrargyrum meaning liquid silver. It is heavy, silver-white metal, liquid at ordinary temperatures. Stable in air and water. Unreactive with alkalis and most acids. Gives off poisonous vapour. Chronic cumulative effects. Mercury only rarely occurs free in nature. The chief ore is cinnabar or mercury sulfide (HgS). Used in thermometers, barometers and batteries. Also used in electrical switches and mercury-vapour lighting products.
meta position → meta položaj
Meta position in organic chemistry is the one in which there are two same functional groups tied to a ring of benzene in position 1 and 3. The abbreviation m- is used, for example, m-Hydroquinone is 1,3-dihydroxybenzene.
metal → metal
Metals are materials in which the highest occupied energy band (conduction band) is only partially filled with electrons.
Their physical properties generally include:
- They are good conductors of heat and electricity. The electrical conductivity of metals generally decreases with temperature.
- They are malleable and ductile in their solid state.
- They show metallic lustre.
- They are opaque.
- They have high density.
- They are solids (except mercury)
- They have a crystal structure in which each atom is surrounded by eight to twelve near neighbours
Their chemical properties generally are:
- They have one to four valence electrons.
- They have low ionisation potentials; they readily lose electrons.
- They are good reducing agents.
- They have hydroxides which are bases or amphoteric.
- They are electropositive.
Metallic characteristics of the elements decrease and non-metallic characteristics increase with the increase of valence electrons. Also metallic characteristics increase with the number of electron shells. Therefore, there is no sharp dividing line between the metals and non-metals.
Of the 114 elements now known, only 17 show primarily non-metallic characteristics, 7 others are metalloids, and 89 may be classed as metals.
metallic glass → metalno staklo
Certain alloys can solidify by extremely rapid cooling out of melt without formation of a crystal lattice, that is in the amorphous form - such, amorphous alloys are so called metallic glasses. The alloy of zirconium, beryllium, titanium, copper, and nickel is one of the first metallic glasses that can be made in bulk and formed into strong, hard, useful objects.
Unlike pure metals and most metal alloys, metallic glasses have no regular crystalline structure. This lack of long range order or microstructure is related to such desirable features as strength and low damping which is one reason why the premier use for zirconium-based metallic glass is in the manufacture of expensive golf club heads. Metallic glasses can be quite strong yet highly elastic, and they can also be quite tough (resistant to fracture). Even more interesting are the thermal properties; for instance, just like an oxide glass, there is a temperature (called the glass transition temperature) above which a metallic glass becomes quite soft and flows easily. This means that there are lots of opportunities for easily forming metallic glasses into complex shapes.
methionine → metionin
Methionine is neutral amino acids with polar side chains. It is one of the two sulfur-containing amino acids. Methionine is a fairly hydrophobic amino acid and typically found buried within the interior of a protein. It can form stacking interactions with the aromatic moieties of tryptophan, phenylalanine, and tyrosine. It is an essential amino acid, which means that humans cannot synthesize it, so it must be ingested.
- Abbreviations: Met, M
- IUPAC name: 2-amino-4-methylsulfanylbutanoic acid
- Molecular formula: C5H11NO2S
- Molecular weight: 149.21 g/mol
Citing this page:
Generalic, Eni. "Ledište." Croatian-English Chemistry Dictionary & Glossary. 29 June 2022. KTF-Split. {Date of access}. <https://glossary.periodni.com>.
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