أكاديميا - كولنز - معاجم الجيب العلمية - الكيمياء - انكليزي - فرنسي - عربي الحرف ٥_ s

Academia - Collins - Pocket Scientific Dictionaries - Chemistry - English - French - Arabic Letter 5_ S


steel
acier m

Alloy steel containing iron as the main component. Materials with different properties can be formed depending on the other elements present in the mixture. The two most famous steels are mild steel, which is used in car bodies and household appliances such as ovens and refrigerators. ..etc., and stainless steel, which is used in industry and cooking utensils. Mild steel rusts easily, so it should be protected by galvanizing, enamelling or painting. Stainless steel does not corrode in the presence of oxygen, which makes it very useful.

Iron produced in a blast furnace contains impurities that make it brittle, such as carbon. Iron is converted into steel by blowing oxygen through the molten iron, which oxidizes the impurities. Then the appropriate and correct quantities of other elements can be added to produce the required steel, such as stainless steel.


STP

Standard temperature and pressure. Abbreviation standard temperature and pressure. The conditions referred to are the pressure of one atmosphere and the temperature (Kelvin 273°C) 0°C. It is useful to have standard conditions to refer to when comparing the volumes of gases.

strength of acids and bases
titre m des acides and des bases

Strength of Acids and Bases Acids and bases are called strong if they are completely dissociated in solution. Good examples are acids such as hydrochloric acid, nitric acid, and sulfuric acid, and bases such as sodium hydroxide and potassium hydroxide.

(Aqueous) -CI + (Aqueous) +H = (Aqueous) HCI
pH range 2 - 1 pH

NaOH (aqueous) = Na+ (aqueous) + OH- (aqueous)

pH range 13 - 14 pH

Weak acids and bases do not dissociate completely in solution. The balance here remains to the left. Good examples can be found in organic acids such as citric acid, tartaric acid, ethanoic acid, and malic acid, and in bases such as ammonia.

CH3COOH (aqueous) = CH3COO- (aqueous) + H+ (aqueous)

pH range 6 - 3 pH

NH3 (aqueous) (aqueous) OH + (aqueous) 4+NH = (liquid) H2O

pH range 11 - 8 pH


strong acids and bases
acids and bases forts

Strong acids and bases.
See strengths of acids and bases.


structural formula f de constitution

Structural formula. A formula showing the bond between atoms and the positions of the atoms relative to each other. The molecular formula shows the number of atoms in the molecule.

Etan C2H6
Ethanol C2H5OH
Molecular formula
Structural formula


subatomic particles
Particulars fpl subatomiques

Subatomic particles. Particles found within an atom. The most important are the proton, the neutron, and the electron.


sublime
sublimer

It sublimates. A substance sublimates if it moves from the solid state directly to the gaseous state when heated, or if it changes from vapor directly to a solid upon cooling. Common materials that sublimate are:
Iron chloride (FeCl2(II).
Carbon dioxide CO2


substitution reaction
Reaction of substitution

substitution reaction. A reaction in which some atoms or groups in a molecule are replaced by others. It is a common reaction for organic compounds.

Example :

CH4 + Cl2 → CH3CI + HCI)
(gas) (liquid) (gas) (gas)

The C-CI bond was replaced by a C-H bond.


sucrose (C12H22O11)
saccharose m

Sucrose. Table sugar. A disaccharide composed of a fructose unit and a glucose unit. It is white crystalline sugar used at home. It is obtained from sugar beets and sugar cane.