أكاديميا - كولنز - معاجم الجيب العلمية - الكيمياء - انكليزي - فرنسي - عربي الحرف ٢_ n

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nitrate
nitrate m

Nitrogens. Nitrogens contain a NO3 group with a value of 1. These are salts of nitric acid and can be made by treating a metal's carbonate or oxide with a dilute acid:

CuCO3 + 2HNO3 → Cu(NO3)2 + H2O
(liquid) (aqueous) (liquid) (solid)

ZnO + 2HNO3 → Zn(NO3)2 + H2O
(liquid) (aqueous) (liquid) (solid)

Nitrogens are easily broken down by heat. And there
Three types of interactions:

(a) (gas) O2 + (solid) 3KNO2 → (solid) 2KNO3

Examples: sodium, potassium.

(b) 2Cu(NO3)2 → 2CuO + O2 + 4NO2
(gas) (gas) (solid) (solid)

All metal nitrogens except those mentioned in (a) and (c).

(c) 2AgNO3 → 2Ag + 2NO2 + O2
(gas) (gas) (solid) (solid)

Examples: silver, mercury.
Azotes are important fertilizers, such as sodium nitrate and ammonium nitrate. If these fertilizers are used incorrectly, they may lead to serious water pollution.


nitric acid (HNO3)
acid m nitric acid

Nitric acid. This colorless, irritating liquid is made from ammonia by oxidation over a platinum/rhodium catalyst. There are three stages:

4NH3 + 502 → 4NO + 6H2O
(gas) (gas) (gas) (gas)

4NO(gas) + 2N0(gas) → 4N2O(gas)

4NH2 + 2H2O + O2 → 4HNO3
(aqueous) (gas) (liquid) (gas)

The acid is distilled to a concentration of 68%, and it can be prepared in the laboratory by heating the nitrogen with concentrated sulfuric acid:

KNO3 + H2SO4 → KHSO4 + HNO3
(gas) (solid) (water) (solid)

Nitric acid is a strong oxidizing agent used in the production of fertilizers and explosives. Nitric acid salts are called nitrates. See nitrogen nitrites and oxides.

nitrites
nitrites mpl

Azotetate. Nitrite. Nitric acid salts (HNO2). Sodium and potassium salts can be made by heating nitrogenes:

2NaNO3 (solid) 2NaNO2 (solid) + O2 (gas)

These salts are used to preserve meat.


nitrogen (N2)
nitrogene m. azote m

Nitrogen. A non-metallic element in group 7 of the periodic table. It is a non-reactive, diatomic gas that constitutes about 78 percent of the atmosphere, and is made by fractional distillation of liquid air.

Nitrogen is an important chemical substance due to the need for nitric acid and ammonia. It is installed from the air using the Haber process.
See nitrogen cycle and nitrogen oxides.


nitrogen cycle
Cycle m de l'azote

Nitrogen cycle. The illustration shows the way in which animals, plants, and humans intervene in the chemical bonds between nitrogen, ammonia, and nitrates. Nitrogen is fixed from the atmosphere by:

A) Haber process.
b) Electrical discharge (lightning).
C) Action of soil microbes.

Plants take nitrogen from the soil, and then animals eat the plants. Animal and plant protein can decay and turn into ammonia. Likewise, animals excrete urine, which breaks down into ammonia. Nitrogen is returned to the atmosphere by other bacteria.
Although humans extract nitrogen from the air using the Haber process, the amount of nitrogen in the atmosphere remains approximately constant.


nitrogen oxides
oxydes plus d'azote

Nitrogen oxides.

Nitric monoxide NO

A colorless gas that can be produced by the action of medium concentration nitric acid in copper. The gas immediately reacts with oxygen to form nitrogen dioxide:

2NO + O2 → 2NO2
(gas) (gas) (gas)

Nitrogen dioxide NO2

Brown gas. It has a suffocating odor and irritates the lungs and trachea. Inhaling this gas can lead to death from pneumonia. It can be produced in the laboratory by the action of nitric acid on copper.

Nitric oxide N2O

A colorless gas with a sweet odor.
It is an anesthetic and is used in dentistry and treatment. Sometimes called laughing gas.