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Compounds of Nitrogen
NITROGEN and PHOSPHORUS
Introduction
? In the group N and P are nonmetals, As and Sb are metalloid, Bi is a metal.
? All have allotropes, except nitrogen and bismuth.
? Phosphorus has white, red and black allotropes. Arsenic has black, yellow and grey allotropes.
? All elements are solid at room conditions except nitrogen.
? Nitrogen is discovered in Scotland in 1772 by Daniel Rutherford.
| Isotopes | 1st Ionization energy |
| 14N, and 15N | 1402.3 kj/mol |
| Earth`s crust abundance | Common oxidation num. |
| 0.00% | -3, -2,-1,+1,+2,+3,+4,+5 |
| Electron configuration | Physical state |
| [He]2s22p3 | gas |
| Melting point | Color |
| -210.10C | colorless |
| Boiling point | Density |
| -195.80C | 1.25x10-3 g/L |
Nitrogen
? Elemental nitrogen is a colorless, odorless,tasteless and mostly inert gas.
? Other name is ?Azot? means dead in Latin language.
? It is little soluble water and lighter than air.
? It makes diatomic structure, N2, and quite inactive element, because of the strong triple bond between nitrogen atoms.
Occurrence of Nitrogen
? It is found in atmosphere 78% by volume, in Earth?s crust as KNO3 and NaNO3, and in all living organisms.
Preparation; In industry
it is obtained by fractional distillation of liquefied air. Nitrogen evaporates first during the distillation.
In laboratory
NaNO2 + NH4Cl → NaCl + 2H2O + N2(g)
2Cu(s) + 2N2 + O2 → 2CuO(s) + 2N2(g)
? Following reaction is applied to airbag systems in cars.
2NaN3(s) → 2Na(s) + 3N2(g)
Chemical Properties of Nitrogen
? Nitrogen may take all oxidation numbers between -3 and +5.(:N≡N:) Bond between N atoms is very strong that is why N2 does not react with acids, bases, water and halogens.
? At high temperatures, it reacts with active metals.
6Na + N2 → 2Na3N
? At 300 atm. pressure and 500 0C temperature, nitrogen gas react with H2 .(Haber Method).
N2(g) + 3H2(g) → 2NH3(g)
? At 25000C or in high electrical current (lightning).
N2(g) + O2(g) Û 2NO(g)
Compounds of Nitrogen
Ammonia, NH3
? It is colorless gas, with a sharp smell,
? It has lower density than air,
? Its boiling point is -33.4 0C and freezing point is -77.8 0C,
? It has very high solubility in water and it is a weak base.
? It is produced with Haber Method in industry;
N2(g) + 3H2(g) → 2NH3(g)
In the laboratory,
NH4Cl(aq) + NaOH(aq) → NaCl(aq) + H2O(l) + NH3(g)
Haber, Fritz (1868-1935), German chemist and Nobel laureate, best known for his development of an economical method of ammonia synthesis.
Ammonia, NH3, Reactions
? React with acids and give salts,
NH3(g) + HCl(g) → NH4Cl(s)
? Forms ammonium hydroxide in water,
NH3(g) + H2O(l) → NH4OH(aq)
? React with pure oxygen,
4NH3(g) + 3O2(g) → 2N2(g)+ 6H2O(g)
? Good reducing agent.
2NH3(g) + 3CuO(s) → 2Cu(s)+ N2(g)+3H2O(g)
Nitric Acid, HNO3
? It is a colorless liquid with 5.2 g/ml.
? Nitric acid is the third most important industrial acid (after sulfuric and phosphoric acid). It is used to prepare fertilizers, explosives, nylon and plastics.
? It is produced in the laboratory,
NaNO3(s) + H2SO4(aq) → NaHSO4(aq) + HNO3(aq)
? In industry it is obtained by Ostwald Process;
4NH3 + 5O2 → 4NO + 6H2O
2NO + O2 → 2NO2
3NO2 + H2O → 2HNO3 + NO
Oxides of Nitrogen
Dinitrogen Monoxide, N2O
? It is common name is nitrous oxide or laughing gas.
? It is used as a mild anesthetic by dentists.
? Little amount is exist in atmosphere.
? It is also used as an oxidizer in rocketry and in motor racing to increase the power output of engines.
? Prepared by decomposition of ammonium nitrate.
NH4NO3(s) → N2O(g)+ 2H2O(g)
 |
Nitrogen Monoxide, NO
? It is common name is nitric oxide. Colorless gas can be produced by the reaction,
3Cu(s) + 8HNO3(dil.) → 3Cu(NO3)2(aq) + 4H2O(l) + 2NO(g)
? NO gas is produced by lightning in a nitrogen and oxygen gas mixture. N2(g) + O2(g) → 2NO(g)
? It is also an air pollutant produced by cigarette smoke, automobile engines and power plants. React with oxygen and forms NO2. 2NO(g) + O2(g) → 2NO2(g)
Nitrogen Dioxide, NO2
? A reddish-brown gas that is produced when the nitrates of the heavy metals are heated.
2Pb(NO3)2(s) → 2PbO(s) + O2(g) + 4NO2(g)
? In the laboratory it is produced by reaction,
Cu(s) + 4HNO3(aq) → Cu(NO3)2(aq) + 2H2O(l) + 2NO2(g)
? Dissolves in water, forms nitric and nitrous acids.
2NO2(g) + H2O(l) → HNO2(aq) + HNO3(aq)
? NO2 is always found together with N2O4 in equilibrium. 2NO2(g) ↔ N2O4(g)
Phosphorus
| Discovered:In 1669 by | 1st Ionization energy |
| Henning Brandt in urine. | 1011.8 kj/mol |
| Earth`s crust abundance | Common oxidation num. |
| 0.10% | -3, +3,+5 |
| Electron configuration | Physical state |
| [Ne]3s23p3 | Solid |
| Melting point | Color |
| 44.20C | Red, White, Black |
| Boiling point | Density |
| 2770C | 1.8 g/ml |
? Phosphorus, is called ?spreader of light? in Latin language.
? It is very reactive nonmetal.
? It is essential constituent of living organisms, found in bones and teeth. Many proteins, in seeds, eggs, nerve tissues and brain cells contain phosphorus. It makes up 1% of human body.
Date: 2016-06-12; view: 35
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