أكاديميا - كولنز - معاجم الجيب العلمية - الكيمياء - انكليزي - فرنسي - عربي الحرف ٢_ m

Academia - Collins - Pocket Scientific Dictionaries - Chemistry - English - French - Arabic Letter 2_ M


mass
Masse f

Mass . The amount of substance present in an object, usually measured in grams (g) or kilograms (kg).


mass number (A)
number m massique

Mass number. The mass number of an isotope is the sum of the number of protons and neutrons in the nucleus of the atom. This number appears on the upper left side of the symbol indicating the isotope (the bottom number is the atomic number).

Examples:

238/92 U 208/82Pb 40/20 Ca 23/11 Na 12/6C 1/1 H


melting
fusion f

fusion. A solid melts and becomes a liquid when the energy of the bridges is sufficient to break up the bonds that maintain its cohesion in the lattice network. Melting occurs for a pure substance at a certain temperature, which is the melting point. Some bonds remain, but the groups of particles become mobile.

(liquid) melting < mesh (solid)
Network disintegration

melting point
point m de fusion

Melting point is the temperature at which a solid melts to form a liquid (or a liquid solidifies to become a solid. More precisely, it is the temperature at which a solid and a liquid of the same substance such as ice/water) are in equilibrium. If the pressure is constant, the melting point is constant for a pure substance, but it decreases if there are impurities, and therefore ice melts if it is sprinkled with salt.


mercury
Mercure m

Mercury. Metal is the only metal that is liquid at normal temperature. It is used in making amalgams and in electrolysis cells as a cathode and in thermometers. Its compounds are highly toxic, such as its vapor.

metal
metal m

Metal . Metals make up 17 percent of the elements, and the following paragraph contains the general properties of metals. Pure metals are rarely used these days, but most of them are used in the form of alloys, and these play an essential role in our lives.

Stalactite minerals produce cations and react with acids. It is strong, tough, malleable and ductile, a good conductor of heat and electricity, and interacts with non-metals. It has a crystalline structure, appears shiny, and has high melting and boiling points.


metalloid
metalloïde m

Semi-metallic. These elements are neither metals nor nonmetals, but rather they are quasi-metals. The best examples of semimetals are germanium and arsenic. These materials have the physical properties of metals, such as a shiny appearance and high melting and boiling points, and the chemical properties of non-metals, such as not reacting with acids. They are useful as semiconductors.


methane
méthane m

A gaseous alkane, which is the main component
For natural gas, it is also released during petroleum processing. The matan burns immediately to give carbon dioxide and water, and forms an industrial source of hydrogen.


methanol
méthanol m

Methanol is a colorless, toxic liquid. It is added to ethanol to make methylated spirits.


methylated spirits
Alcool m dénaturé


H H-C-O H CH3OH H

Oxidized methyl alcohols. A mixture of ethanol (90% ethanol), methanol (9.5% methanol), pyridine (0.5%), and a very small amount of purple dye.

This mixture is made to make ethanol undrinkable. It is used as fuel and as a solvent.

methylbenzene (formerly toluene) methylbenzene m

(formerly methyl benzene). An aromatic hydrocarbon produced from petroleum. It is used to make T-N explosives. TriuNitro Toluene, which is useful as a solvent
Also solvent.



methyl orange
methylorange m

Metyl orange. Acid-base indicator.

Alkaline solution is yellow <---> Acidic solution is orange/red