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

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


salt
sel m

salt . A compound is formed when a metal is replaced with hydrogen, all or part of an acid. For example:

Zn + HCI → ZnCl2 + H2
(gas) (aqueous) (aqueous) (solid)

When an acid reacts with a base, the product is only salt and water:

NaOH + HNO3 → NaNO3 + H2O
(liquid) (aqueous) (aqueous) (aqueous)

Salts can also be made by direct combination
Two elements:

2Na (solid) + Cl2 (gas) → 2NaCI (solid)

If there is a dibasic acid and one hydrogen atom is replaced in it, the result is an acid salt.

The name of the salt reveals how it is formed. For example: magnesium sulfate is formed from magnesium and sulfuric acid:

Mg + H2SO4 → MgSO2 + H2
(gas) (aqueous) (aqueous) (solid)


saponification
saponification f

Saponify. The process of hydrolysis of ester when using alkaline conditions. An example of saponification is the breakdown of natural fats to produce soap. Here, sodium hydroxide solution is used to produce alcohol and sodium salt of detergent acid
(soap). See carboxylic.


saturated compound
Composé m sature

Saturated compound. An organic compound that contains only single bonds. Compounds that contain double or triple bonds are called unsaturated compounds.

Examples:
Bhutan - l - l
Etan


saturated solution
Solution in nature

Saturated solution. A solution contains the maximum amount of solute at a given temperature in the presence of excess solute. The amount of solute needed to form a saturated solution depends on the temperature. The only way to add more solute to a saturated solution is to change the temperature.
See supersaturated solution.


second(s)
second f

second. The unit of time in the International System of Units (SI).


semiconductor
semiconductor m

semi-conductor conveyor. An electrical conductor with unusual properties. The resistance of this material decreases as the temperature increases or as the amount of impurities in the material increases. In practice, specific amounts of impurities are added to the crystals of the semi-conducting material when they are formed to obtain exactly the desired properties.
Substances with semiconducting properties may be elements or compounds, but are usually metalloids. Examples include: gallium, germanium, and arsenic.


separation of mixtures
Séparation ƒ of the language

Separation of mixtures. Mixtures can be separated if the substances in the mixture have different physical properties. The technique used in separation depends on the quality of the mixture. The techniques used include: filtration, fractional distillation, chromatography, and decantation.


shell
couch f

Electronic cover.
See electronic configuration.


Si units
unité f MKS

International system of units. An international system of units based on the metric measurement system. There are seven basic modules (listed below). This system is used in scientific and technological work all over the world.

Quantity -------- Unit

- Length ------ meters
- Mass ------ kilograms
- Time ------ seconds
- Current ------ amps
- Temperature ------ Kelvin
- Quantity of substance ------ mole
- Brightness intensity ------ lumens