CHEMICALS
Chemical components and chemical substance
When we refer to chemicals, we refer to a component that has some definite characteristic. And when we refer to a chemical substance, it refers to a material that has a definite composition which will remain unaltered irrespective of its sources. Water will continue to be a combination of H2O irrespective of its source. Here water is the chemical substance whereas hydrogen and oxygen are the chemical components. The basic difference of a chemical substance from pure substance is that the chemical substance, unlike a pure substance, can be broken into components. For example, common salt used at home is a chemical substance that can be easily broken into chloride and sodium through laboratory processes. The proponent of the concept of chemical substance was Joseph Proust.
Chemical elements
An element is a substance that can not be broken into different component substances. Similarly, a chemical element cannot be broken into different chemical. For example, water as a chemical compound can be broken into hydrogen and oxygen. But hydrogen cannot be further broken and therefore is a chemical element. An element consists of atoms. Atoms consist of a negatively charged electron, a positively charged proton and an uncharged neutron. There are in all one hundred twenty elements of whom eight are stable. These stable elements do not have radioactive decay changing them into other elements.
Chemical compounds
When two or more elements combine to form a substance having molecules, it is called a chemical compound. There are two types of chemical compounds. These are organic chemical compounds, a combination of carbon and hydrogen, and inorganic chemical compounds.
Chemical mixtures
Chemical mixtures are derived by combining chemical elements with chemical compounds. However, there is no fixed composition specified for a mixture. The components can be separated into their original forms. For example, grey iron and yellow sulfur combines to make a yellow grey mixture though individually they are separate elements. But the same chemical substances can be processed through a chemical formulae to obtain a new chemical substance altogether.
Identifying chemicals
A unique chemical system name identifies each chemical substance. The names are given according to the IUPAC rules or the alternative CAS rules. However, there are a number of chemical substances that are known by their older names which were given before they were given a chemical name. Common salt is more known name than Sodium bicarbonate. However, the scientists refer to chemical names while referring to chemical substances. For example, the common name alcohol has the systematic name of ethanol and chemical formula of C2H5OH. |
