أكاديميا - كولنز - معاجم الجيب العلمية - الكيمياء - انكليزي - فرنسي - عربي الحرف ١_ g

Academia - Collins - Pocket Scientific Dictionaries - Chemistry - English - French - Arabic Letter 1_ G


(g). A state symbol used to indicate that a substance is a gas:

CO2(na), O2(na) NH3(na), H2O(na), H2(na)


galvanizing
galvanization f

Galvanization. Iron and steel sheets are often coated with a thin layer of zinc, which is called galvanized iron. Zinc is more resistant to corrosion than iron and can therefore protect it. On the other hand, if the coating is scratched and the iron and zinc are in contact with a liquid, and an electrochemical cell is operated, the zinc reacts instead of the iron, as it is more reactive. Thus, galvanization protects the iron even when the protective layer is cracked.


gamma rays
rayons mpl gamma

Gamma rays. A form of high-energy electromagnetic radiation. These rays are generated through nuclear reactions and have great penetrating capabilities. Gamma rays are similar to X-rays and are used to treat cancer, as they kill cell bodies. They are also used to sterilize materials.

gas. gas
gaz m

A state of matter gas in which atoms and molecules have few bonds with each other, and therefore have great freedom of movement, moving very quickly in random directions. When a liquid is provided with thermal energy, the atoms or molecules gain more kinetic energy, and this energy may be sufficient to overcome their cohesive bonds in the case of a liquid. If this happens, the liquid boils and turns into a gas or vapor. In the gas, the atoms or molecules fill all parts of the container, and their collision with the walls of the container exerts pressure.

gas laws
Lois fpl des gas

Gas laws. If we combine Boyle's law and Charles's law, we find that for a gas with a specific mass:

Pressure (P) x Volume (7) / Temperature (T)
= fixed

Or PV /T = constant (T in Kelvin)

This means that if we compare gases under different conditions, such as different temperature and pressure, we find:

Constant = P2V2/T2 and = P1V1/T1
Case 2 and Case 1

This allows us to obtain very useful information about gases by calculation rather than by measurement. See STP.

general formula
General formula

General formula. Reference to organic chemistry. It is a formula that shows the relative numbers of different atoms according to the variable “n” for each member of a specific family of compounds. The actual formula of a specific compound is found by replacing, for example, the general formula for alkanes is CnH2n+2.

Methane has 1 carbon... n = 1... formula = CH4

Butane has 4 carbons... n = 4... formula = C4H10


giant structure
Structure of the entity

Giant structure. Molecules are made up of small numbers of atoms bonded together. In giant structures of atoms or ions, there are large numbers of particles present in a crystal lattice. Each particle has a strong gravitational force that it exerts on other particles close to it. In this way, gravitational forces spread throughout the structure, and melting and boiling points tend to rise in giant structures. Ionic substances have giant structures, as do most elements, such as all metals and many non-metals.


glass
verre m

Glass is a hard, transparent mixture of silicate types. The cheapest and most common type of glass is called soda glass, and it is made by heating sand, sodium carbonate, calcium oxide, and broken glass together. The hot liquid cools very slowly, as slow cooling means that the glass does not crystallize, and the glass is a supercooled liquid.

In lead glass, lead (II) oxide is replaced by sodium carbonate, giving a glass with a high index of refraction that is used in making glass tools.
Crystal. See borosilicate glass.


glucose
glucose m

Glucose. The monosaccharide molecule is found in honey, golden syrup, and fruits. All the sugar and starch that enter our bodies turns into glucose, which is then used to provide energy.