أكاديميا - كولنز - معاجم الجيب العلمية - الكيمياء - انكليزي - فرنسي - عربي الحرف ٤_ s

Academia - Collins - Pocket Scientific Dictionaries - Chemistry - English - French - Arabic Letter 4_ S


Solvay process
Procédé m de Solvay

Solvay process. This process takes cheap raw materials (brine and calcium carbonate - limestone) and turns them into a valuable alkali substance, sodium carbonate:

2NaCl + CaCO3 → CaCl2 + N2CO3
(aqueous) (aqueous) (solid) (aqueous)

Because sodium carbonate and calcium chloride both dissolve in water, the aforementioned equation cannot be performed directly, but rather in a series of steps:

(a) The limestone is heated:

CaCO3 → CaO + CO2
(gas) (solid) (solid)

(b) Ammonia is dissolved in brine, NaCl + NH3. (c) Carbon dioxide (produced from limestone) is passed into the brine/ammonium solution, and the following reaction occurs:

NaCl + CO2 + NH3 + H2O → NaHCO3 + NH4CI
(aqueous) (solid) (liquid) (gas) (gas) (aqueous)

Sodium hydrogen carbonate is produced due to its poor solubility.
It can be removed from the mix.

(d) Sodium carbonate is produced by heating carbonate
Hydrogen.

2NaHCO3 → Na2CO3 + H2O + CO2
(gas) (liquid) (solid) (solid)

(e) In the final stage, ammonia is recovered from ammonium chloride:

2NH4Cl + CaC → CaCl2 + 2NH3 + H2O
(Liquid) (Gas) (Aqueous) (Solid) (Aqueous)

The ammonia and carbon dioxide produced in the last two stages are recycled and reused. The only side product of the reaction is calcium chloride (CaCl2).

solvent
solve m

Solvent. A liquid in which a solute dissolves to form a solution. Water is the most common solvent. Solvents may be polar, such as water, or nonpolar, such as ether. Polar solvents dissolve ionic or polar solutes, such as salts. Nonpolar solvents dissolve covalent molecules such as hydrocarbons.


spectator
ions mpl spectateurs

Spectator electrolytes do not play any role in the interaction, and remain only spectators. The underlined strays in the following example are spectator strays:

365

Na+ + Cl- + Ag+ + NO3+ → Na+ + NO3 + AgCl
(solid) (aqueous) (aqueous) (aqueous) (aqueous) (aqueous) (aqueous)

And the interaction is
Ag+ + Cl → AgCl
(solid) (aqueous) (aqueous)


stalactites and stalagmites
stalactites fpl et stalagmites

Stalactites and stalagmites. Protrusions found in caves. When water containing calcium slats drips into the cave, there is a gradual accumulation of calcium carbonate down from the ceiling, forming a descending effect and onto the ground (an upward formation), as a result of the disintegration of the solution containing calcium salts.

Ca(HCO3)2 → CaCO3 + H2O + CO2
(gas) (liquid) (solid) (water)


starch(C6H1005)n
amidon m

We want. Polymer carbohydrate: made of glucose monomers and can be broken down by enzymes or dilute acids, forming glucose or maltose. Starch is insoluble in water, is a white, tasteless powder, and is found in most plants that use it as food. Animals also use it as food when they eat plants such as potatoes, rice, and flour. The iodine solution turns blue in the presence of starch, and this transformation can be used as a test for either starch or iodine. See polysaccharide.


states of matter
This includes the mat

States of matter. Substances can be in three states: solid, liquid, and gas. Matter moves from one state to another by changing temperature.


state symbols
Symbols for text

Status codes. Letters placed (in English) after the formula of a substance, usually between parentheses in a chemical equation, to indicate the state of that substance in the reaction. The letters are: (s) for solid, (I) for liquid, (g) for gaseous, and (aq) for aqueous solution, such as:

2Na (solid) + 2H2O (liquid) → 2NaOH (aqueous) + H2 (gas)