Non – metal oxides are inorganic chemical compounds formed by oxygen atoms with atoms of nonmetallic elements . Among these chemical elements are Hydrogen, Carbon, Nitrogen, Phosphorus, Sulfur, Halogens.
As they are considered to be derivatives of the oxyacids, but with a less water molecule, they are also called anhydrides .
Characteristics and Properties of Non-Metals
The properties of non-metals are more varied than those of metals. Some non-metals are gases in elementary state : Hydrogen, Oxygen, Nitrogen, Fluorine, Chlorine and the noble gases. Only one, Bromo, is a liquid. All other non-metals are solid at room temperature.
Unlike metals, non-metallic elements are poor conductors of heat and electricity , and can have both positive and negative oxidation numbers.
Non-metals are more electronegative than metals. The electronegativity is the ability of an atom to attract others to form a bond . The electronegativity of the elements increases from left to right over any period and from bottom to top in any group of the periodic table. The element Fluorine has the highest electronegativity of the whole table, with a value of 4 . Non-metals are concentrated in the upper right part of the periodic table.
Nevertheless, halogens rarely participate in bonds with the oxygen to form anhydrides. Rather, they engage in more complex compounds, such as Oxisals.
The Hydrogen Oxide is also called ” Water “, and is made up of two Hydrogen atoms and one oxygen atom. ( H 2 O ). Its molar mass is 18.02 g / mol.
Its structure is angular, with an “L” shape that has the oxygen in the center. It is able to form Hydrogen Bridge Links , which allow more cohesion between molecules, and therefore a higher Density.
Its density is 1.00 g / cm 3 , making it one of the most dense liquids. Its melting point is at 0 ° C, and its boiling point is at a temperature of 100 ° C.
The isotope of Hydrogen Deuterium (D 2 ) also has its corresponding oxide, D 2 O , whose molar mass is 20.03 g / mol. Its density is 1,108 g / cm 3 . Its Melting Point is at 3.8 ° C and its Boiling Point is at 101.4 ° C.
Carbon joins Oxygen in two different ways: as Carbon Monoxide CO and as Carbon Dioxide CO 2 .
The carbon monoxide CO is a colorless, odorless gas formed by incomplete combustion of carbon or compounds containing carbon.
2C (s) + O 2 (g) -> 2CO (g)
Carbon Monoxide is used in metallurgical processes for the extraction of nickel, in organic synthesis and, with hydrogen, in the production of combustible hydrocarbons. In the industry it is prepared by passing water vapor over hot coke.
Carbon Monoxide burns quickly in the presence of Oxygen to form Carbon Dioxide.
2CO (g) + O 2 (g) -> 2CO 2 (g)
Carbon Monoxide CO is found in the exhaust gases of cars, and has high toxicity. When breathed in, Carbon Monoxide CO is structurally added to Hemoglobin Hb . The forms carboxyhemoglobin COHb , which prevents properly capture and transport oxygen to the blood.
The carbon dioxide is a colorless and odorless gas. Unlike Carbon Monoxide, CO 2 is not toxic. It is produced in the Complete Combustion of materials formed by Carbon, such as Methane CH 4 :
CH 4 + 2 O 2 -> CO 2 + 2 H 2 O
Carbon Dioxide is used in soft drinks, in fire extinguishers and in the manufacture of baking powder (NaHCO 3 Sodium Bicarbonate ) and Na 2CO 3 commercial soda . Solid Carbon Dioxide, known as dry ice, is used as a coolant . Also, in liquid form, Carbon Dioxide is used as a solvent to extract compounds such as vanillin and caffeine.
Oxides of Nitrogen
There are many Nitrogen Oxides, but the three most important are: Nitrous Oxide N 2 O, Nitric Oxide NO and Nitrogen Dioxide NO 2 .
The Nitrous Oxide N 2 O is a colorless gas with a pleasant scent and sweet flavor. It is prepared by heating Ammonium Nitrate to approximately 270 ° C:
NH 4 NO 3 (s) -> N 2 O (g) + 2H 2 O (g)
Nitrous Oxide N 2 O resembles molecular oxygen in the fact that it allows combustion. This is because when heated, it decomposes to form molecular Nitrogen and Oxygen:
2N 2 O (g) -> 2N 2 (g) + O 2 (g)
It is used mainly as a dental anesthetic and in other minor surgeries . Nitrous oxide is also known as “laughing gas” because it produces excitement in the person who inhales it. No satisfactory explanation has yet been given to this peculiar physiological response.
Nitrous Oxide is also used as a propellant in chantilly cream cans due to its high solubility in the chantilly cream mixture.
The nitric oxide NO, is a colorless gas. The reaction of N 2 and O 2 in the atmosphere is a form of nitrogen fixation.
N 2 (g) + O 2 (g) -> 2NO (g)
In the atmosphere an appreciable amount of nitric oxide is formed when lightning strikes .
The nitrogen dioxide NO 2 is a highly toxic yellowish brown gas with a suffocating odor. It is paramagnetic and has a strong tendency to dimerize forming DiNitrogen Tetroxide N 2 O 4 , which is a diamagnetic molecule.
2NO 2 -> N 2 O 4
Nitrogen dioxide is an acid oxide, which reacts rapidly with cold water to form both nitrous acid, HNO 2 , and Nitric acid:
2NO 2 (g) + H 2 O (l) -> HNO 2 (ac) + HNO 3 (ac)
The two important oxides of phosphorus are tetraphosphorus hexaoxide, P 4O 6 , and tetraphosphorus Decanoxide, P 4 O 10 . The oxides are obtained by burning the white phosphorus in a limited amount and in excess of gaseous oxygen, respectively:
P 4 (s) + 3O 2 (s) -> P 4 O 6 (s)
P 4 (s) + 5O 2 (g) -> P 4 O 10 (s)
Both oxides become acids in the water. Compound P 4 O 10 is a white, flocculent powder that has a high affinity for water. Form Phosphoric Acid H 3PO 4 in it. For this reason it is usually used to dry gases and to remove water from solvents.
Sulfur has two important oxides: Sulfur Dioxide SO 2 and Sulfur Trioxide SO 3 .
The sulfur dioxide SO 2 is formed when the sulfur is burned in the air:
S (s) + O 2 (g) -> SO 2 (g)
Sulfur dioxide, whose boiling point is -10 ° C, is a colorless gas with a pungent odor, quite toxic. It becomes Sulfuric Acid H 2 SO 3 upon contact with water.
Sulfur Dioxide SO 2 is slowly oxidized to sulfur trioxide, but the rate of reaction can be accelerated considerably with a catalyst such as platinum or Vanadium Oxide:
2SO 2 (g) + O 2 (g) -> 2SO 3 (g)
Sulfur Trioxide SO 3 dissolves in H 2 O water to form Sulfuric Acid H 2 SO 4 , a reaction that also occurs at the environmental level under the name of Acid Rain , a phenomenon that wears away the mineral substances on which it is deposited. rush.
SO 3 (g) + H 2 O (l) -> H 2 SO 4 (ac)
Examples of Non-Metal Oxides
Hydrogen Oxide or Water H 2 O
Deuterium Oxide D 2 O
Carbon Monoxide CO
Carbon Dioxide CO 2
Nitrous Oxide N 2 O
Nitric Oxide NO
Nitrogen dioxide NO 2
Tetraphosphorus hexa phoxide P 4 O 6
Tetraphosphorus Decanoxide P 4 O 10
Sulfur Dioxide SO 2
Sulfur Trioxide SO 3