أكاديميا - كولنز - معاجم الجيب العلمية - الكيمياء - انكليزي - فرنسي - عربي الحرف ٦_ p

Academia - Collins - Pocket Scientific Dictionaries - Chemistry - English - French - Arabic Letter 6_ P


polymerization
polymerization f

He snarled. The reaction of monomers to form a polymer.

polypeptide
polypeptide m

Polypeptide. A molecule made of up to 50 amino acids linked together by peptide links.
If there are more than 50 amino acids, the molecule is called a protein. Polypeptides are important molecules in the body and function as enzymes.

poly(penylethene) (or polystyrene)
polystyrene m

Polyphenylethene (or polystyrene). An oligomer based polymer based on the alkene phenylethene. It is embossed and widely used as sheets and in extended form. Here, air is blown into the ionizer and the result is a white, granular solid with excellent insulating properties. This ionomer is used to make cups, roofing tiles, and other materials that must be a conductor
Weak.

phenylethn p
no C8H8


poly(propene)
polypropène m

Multi (proin). This polymer is similar to poly(ethene) in that it is an ionomer resulting from an alkene. The alkene is prone (CaHe), which is obtained from petroleum. This ionomer is useful and has many uses. It is strong and does not wear out, and is used as a fiber for making carpets. As a material for making laboratory beakers and beakers, it is highly non-reactive. It is also called polypropylene.


e C3H6 Proin F

Multi (Proin) |


polysaccharides
polysaccharides mpl

Polysaccharides. These polymers consist of sugar molecules such as glucose. There are three examples that are commonly found naturally:

starch
Cellulose
Glycogen

All three of these ionomers are made up of molecules
Glucose in chains.

Polysaccharides can be broken down by hydrolysis into simple sugars, such as glucose, or into disaccharides, such as maltose. Enzymes in plants and animals carry out hydrolysis, but it can also be carried out by acids.
Polysaccharides are valuable foods, such as starch in the form of potatoes or rice. Cellulose is found in all plants, and glycogen is the form in which excess carbohydrates are stored in animals.


poly(tetrafluoroethene) (PTFE) polytetrafluoroethene m

Poly(tetrafluoroethylene). The polymer is very inert. It is the non-stick surface that covers pans, such as Teflon and Fluon. It is also used for bearings because it has a low coefficient of friction.


polythene
polyethylène m

See poly(ethene). This term is still used in industry and commerce.


potassium
potassium m

potassium. A group I metal. A grey-coloured element, very soft and highly reactive. It is easy to cut with a knife, revealing a silvery surface that immediately loses its luster. It is a powerful reducing agent that gives the potassium ion (K):

2K + 2H2O→ 2KOH + H2
(gas) (water) (liquid) (solid)

Potassium is preserved under oil due to its interaction with air and water. The metal ions give a lilac test flame.

Potassium is obtained by electrolysis of molten potassium chloride (KCI).