Practically all elements of the periodic system of Mendeleev can form oxides, or oxides - binary compounds containing oxygen atoms in their molecules. The class of these inorganic compounds, in turn, is divided into several groups: basic, acidic, amphoteric and indifferent oxides. The purpose of our article is to study the physical and chemical properties of oxides, as well as their practical application and significance to humans.
Methods of obtaining
The main chemical reaction for obtaining oxides is the direct interaction of a metal or non-metal with oxygen.
H2 + O2=H2O (the reaction is explosive)
4K + O2=2K2O
Other methods of oxide formation include the combustion of complex substances, such as hydrocarbons. It ends up producing carbon dioxide and water. During the thermal decomposition of water-insoluble bases ors alts: carbonates, nitrates, oxides are also released. Examples of such reactions are given below:
- Fe(OH)2=FeO+H2O iron(II) oxide
- 2KNO3=2KNO2 + O2↑
Physical characteristics
The state of aggregation of binary compounds of oxygen with metals or non-metals can be different. For example, carbon oxides, nitrogen dioxide, sulfur oxide (IV) are gases. Liquids are water, sulfuric anhydride, and metal oxides are solids. The solubility of the compounds is also different. Let us give examples of oxides with varying degrees of interaction with water. So, carbon dioxide dissolves in water at room temperature in a ratio of 1:1, nitric oxide (II) is slightly soluble, and silicon dioxide is insoluble at all.
Basic oxides
If a molecule of a substance contains atoms of typical metals, it exhibits basic properties. The substance will react with acids and acid oxides as well as water. For example, calcium oxide can react with perchloric acid:
2HCl + CaO=CaCl2 + H2O.
The reaction products will be medium s alt and water. If the same calcium oxide interacts with carbon monoxide, then we get one substance - s alt.
CaO + CO2=CaCO3.
The properties of oxides formed by metals have found application in various industries. So, calcium oxide, also called quicklime or burnt lime, is importantas a raw material for the production of slaked lime. Calcium hydroxide is widely used in industry as a building mortar. Lime water is used as an indicator for the presence of carbon dioxide molecules in solution.
Examples of oxides that make up iron ore are FeO and Fe2O3 - brown and magnetic iron ore. In the blast furnace, they are reduced with coke and carbon oxides and an alloy of iron and carbon is obtained - cast iron. In the process of its further processing in the metallurgical industry, various grades of steel are smelted, including alloy steel.
Reaction with water of oxides of alkali or alkaline earth metals leads to the production of alkali.
Characterization of acid oxides
Oxides of nitrogen, carbon, sulfur, silicon, etc. form a group of acidic oxides. The chemical properties of oxides are reactions with alkalis, basic oxides and water. The products of the interaction between potassium hydroxide and carbon dioxide will be potassium carbonate and water. If sodium base and silicon dioxide react with each other, we get sodium silicate and water.
Some acidic oxides react with water. The reaction product will be the corresponding acid (carbonic):
CO2 + H2O=H2CO 3.
Acid oxides, examples of which we will give below, are important. So, sulfuric anhydride SO3 - a colorless liquid, is the feedstock for industrial productionsulfate acid - the main product of the chemical industry. Nitrogen compounds, such as NO2, are used to produce nitrate acid. In addition to nitrogen dioxide, water and oxygen also participate in the reaction. Nitric acid, obtained by the reaction of nitrogen oxides with water, is used in the production of mineral fertilizers, explosives, dyes, medicines, plastics, etc.
Amphoteric compounds
Oxides, which include, for example, zinc or aluminum atoms, exhibit dual chemical properties. They can react with both acids and alkalis. In this case, the reaction products are medium s alts. Here is a description of the physical properties of some amphoteric oxides, examples of which we will consider. So, Al2O3 is corundum, it is a solid substance whose melting point reaches 2050°. In nature, the oxide is part of alumina, and also forms colored crystals, which are precious stones - rubies and sapphires.
Zinc oxide ZnO are colorless crystals, at a temperature of 1800 ° turning into a vapor state. This phenomenon is called sublimation. The substance is insoluble in water, when inhaled dust particles cause poisoning. Zinc oxide has found application as an abrasive material, in the production of paints, artificial leather, in medicine, in dentistry - as a filling material.
In our article, we studied the classification of oxides, their chemical and physical properties, andalso industrial applications.
