2015-04-01
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Nitrogen
Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere. The element nitrogen was discovered as a separable component of air, by Scottish physician Daniel Rutherford, in 1772.
Many industrially important compounds, such as ammonia, nitric acid, organic nitrates (propellants and explosives), and cyanides, contain nitrogen. The extremely strong bond in elemental nitrogen dominates nitrogen chemistry, causing difficulty for both organisms and industry in breaking the bond to convert the N2 into useful compounds, but at the same time causing release of large amounts of often useful energy when the compounds burn, explode, or decay back into nitrogen gas.
Nitrogen occurs in all living organisms, and the nitrogen cycle describes movement of the element from air into the biosphere and organic compounds, then back into the atmosphere. Synthetically-produced nitrates are key ingredients of industrial fertilizers, and also key pollutants in causing theeutrophication of water systems. Nitrogen is a constituent element of amino acids and thus of proteins and nucleic acids (DNA and RNA). It resides in thechemical structure of almost all neurotransmitters, and is a defining component of alkaloids, biological molecules produced by many organisms. The human body contains about 3% by weight of nitrogen, a larger fraction than all elements save oxygen, carbon, and hydrogen.
Nitrogen is formally considered to have been discovered by Daniel Rutherford in 1772, who called it noxious air or fixed air. The fact that there was an element of air that does not support combustion was clear to Rutherford. Nitrogen was also studied at about the same time by Carl Wilhelm Scheele, Henry Cavendish, and Joseph Priestley, who referred to it as burnt air or phlogisticated air. Nitrogen gas was inert enough that Antoine Lavoisier referred to it as "mephitic air" or azote, from the Greek word azotos meaning "lifeless". In it, animals died and flames were extinguished. Lavoisier's name for nitrogen is used in many languages (French, Polish, Russian, etc.) and still remains in English in the common names of many compounds, such as hydrazine and compounds of the azide ion.
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Вариант № 4
1. Переведите предложения, обращая внимание на Participle:
1. Ozone or trioxygen, is a triatomic molecule, consisting of three oxygen atoms.
2. Christian Friedrich Schunbein in 1840, named Ozone after the Greek verb ozein "to smell", from the peculiar odor in lightning storms.
3. The story published in the magazine is not very interesting.
4. Reading books I make many notes.
2. Определите предложения, в которых частица to является признаком инфинитива и правильно переведите все задание:
1. Ozone, the first allotrope of a chemical element to be recognized.
2. At –112 °C, it condenses to form a dark blue liquid.
3. It is dangerous to allow Ozone liquid to warm to its boiling point, because both concentrated gaseous ozone and liquid ozone can detonate.
4. Exposure of 0.1 to 1 mol produces headaches, burning eyes, and irritation to the respiratory passages.
5. Even low concentrations of ozone in air are very destructive to organic materials such as latex, plastics, and animal lung tissue.
3. Переведите предложения, обращая внимание на страдательный залог:
1. Ozone was proposed as a distinct chemical substance by Christian Friedrich Schunbein in 1840.
2. The newspapers are usually brought in the morning.
3. They will be shown a new film tomorrow.
4. The boy was told to be at home at 6 o’clock.
4. Переведите предложения с русского на английский:
1. Я рад, что мне помогают.
2. Тебе нужно помочь?
3. Должно быть ты проголодался?
4. Ваш доклад необходимо поделить на две части.
5. Стоящая у окна девушка – моя сестра.
