أكاديميا - كولنز - معاجم الجيب العلمية - الكيمياء - انكليزي - فرنسي - عربي الحرف ٣_ p

Academia - Collins - Pocket Scientific Dictionaries - Chemistry - English - French - Arabic Letter 3_ P


phenol
phenol m

Fanol. An aromatic, crystalline, colorless solid that turns pink when exposed to air and light.
O-H
C6H5OH

It is a very irritating and toxic substance, and is useful as an antiseptic and disinfectant. Many household products rely on phenol-like molecules, that is, compounds with similar or better disinfection properties but are less irritating, such as T.C.P. and Dettol.
The O-H group in phenol has an acidic hydrogen
Acids can form:

(solid) +C6H6O-N


phenolphthalein
phenolphthaléine f

Phenolphthalein is an indicator used to monitor acid-base reactions, and the molecular structure of the compound is based on the phenol molecule.

Alkaline solution is red <---> Acid solution is colorless


phosphates
phosphates mpl

Phosphate. Salts of phosphoric acid (7) phosphoric acid. Phosphorous acid is a tribasic acid, and therefore it gives three types of salts:

Sodium phosphate Na3PO4

Sodium hydrogen phosphate Na2HPO4

Sodium dihydrogen phosphate NaH2PO4

Phosphates are used in fertilizers to replace phosphorus-containing compounds in the soil. These phosphates come in many forms:

Superphosphate: a mixture of calcium sulfate and dicalcium dihydrogen phosphate (Ca (H2PO4)2).

A mixture of ammonium azotate and ammonium hydrogen phosphate 2HPO4 (NH4) is made.
Activation of ammonia with a mixture of phosphoric acid (7) and nitric acid.

Calcium phosphate: It is the main component of animal bones, and phosphates are widely used in washing powders and detergents.

The slag resulting from blast furnaces is placed directly on the soil because it contains calcium phosphate.

phosphoric (V) acid (H3PO4)
acid m phosphorique

Phosphorous acid (7) is a tribasic acid that gives three types of phosphate. It is a solid at room temperature but is usually sold as a viscous solution in water. It is used in stainless steel because it forms a protective layer of iron phosphate. It is also used in the food and pharmaceutical industries.


phosphorous (P4)
phosphore m

Phosphorous. A solid, non-metallic element in group V of the periodic table. It has three allotropes: white phosphorus, red phosphorus, and black phosphorus. The drawing information refers to white phosphorus.

Invariants have very different physical properties. Such as crystal structure, density, and melting and boiling points.

White phosphorus is very toxic and must be kept under water because it flammables upon contact with air, forming an oxide:

(solid) P4O10 → (gas) 5O2 + (solid) P4 Rocks containing phosphorous compounds are commonly found in the Earth's crust, and are an important element in the maintenance of life. Plants need phosphorus, which makes it an important component of fertilizers, such as premium phosphate.
See phosphates.
Some enzymes used in respiration also contain this element. Animal bones contain phosphates. In earlier days, phosphorus was widely used in making the heads of matchsticks, but this use was banned a long time ago, and current matchsticks contain phosphorus sulfide. In fact, phosphorus is placed in a safety match on the side of the box, which is why the stick does not ignite unless it is rubbed against the box. Just .


photochemical reactions
Reactions fpl photochimiques

Photochemical reactions. Chemical reactions carried out by light. The photographic process depends on,
For example, on light, silver bromide decomposes when exposed to light:

2AgBr (solid) → 2Ag (solid) + Br2 (gas)

The black portion of the film negative is a thin layer of silver that is processed to produce the final image.

Photosynthesis is the most important photochemical reaction, as our existence on the surface of this planet depends on it.

Another example is the reaction between hydrogen and chlorine, which can be triggered by a bright light such as the burning of magnesium:

H2(gas) + Cl2(gas) → 2HCI(gas)

In hot regions of the world, such as the US state of California, where there is a lot of car exhaust smoke, the reaction of this smoke can produce photochemical smog (SMOG), which is a harmful fog.
And very annoying.

Likewise, the bleaching action caused by the sun is a photochemical reaction due to its conversion of skin cholesterol into vitamin D. In all of these cases, light provides the energy that makes the reaction take place.