A chemical compound is a substance formed by the chemical combination of two or more elements of the periodic table . Compounds are represented by a chemical formula . For example, water (H 2 O) it is composed of two atoms of hydrogen and one of oxygen . The elements of a compound cannot be divided or separated by physical processes ( decantation , filtration , distillation ), but only by chemical processes . How are compounds formed
Compounds are made up of molecules or ions with stable bonds that do not obey arbitrary human selection. Therefore, they are not mixtures or alloys like bronze or chocolate . A chemical element attached to an identical chemical element is a chemical compound, as an element involved is only, not two different elements. How are compounds formed
Types of compounds
There are four types of compounds, depending on how the constituent atoms are held together:
- Molecules linked by covalent bonds
- Ionic compounds linked by ionic bonds
- Intermetallic compounds joined by metallic bonds
- Certain complexes held together by coordinated covalent bonds
Many chemical compounds have a unique numerical identifier assigned by the Chemical Abstracts Service (CAS): their CAS number. How are compounds formed
In simple: Compounds are formed when two or more elements are chemically bonded fixed ratio by mass.
As a result of this combination, lose their own properties and produce new substances(compunds)that have entirely different properties. Compounds can not be broken down into their constituents by simple physical methods. How are compounds formed
For example, carbon dioxide is formed when elements of carbon and oxygen combine chemically in a fixed ratio of 12:32 or 3:8 by mass. How are compounds formed
Compounds are divided into two classes as ionic or covalent.
Ionic compounds formation
Ionic compounds do not exist in independent moleculer form. They form a three dimensional crystal lattice in which each ion is surrounded by oppositely charged ions. These oppositely charged ions attract each other very strongly as a result ionic compounds have high melting and boiling points.These compounds are denoted by formula units.e.g.NaCl,KBr,CuSO4.
Covalent compounds formation
The covalent compounds mostly exist in moleculer form. A molecule represents a true covalent compound and it’s formula is called moleculer formula. e. g. H2O,HCL,H2SO4,CH4.
Some common compounds formation and their formulas
Compound chemical formula
Sodium chloride NaCl
Silicon dioxide(sand) SiO2
Sodium hydroxide NaOH
Sodium carbonate Na2CO3.10H2O
Calcium oxide CaO
Calcium carbonate CaCO3
Sulphuric acid H2SO4
Properties of ionic compounds
The ionic compounds have following properties;
- they are mostly crystalline solids.
- In solid state they have negligible electricle conductance.
- They have high melting and boiling points.for exampie Nacl has melting point 800 C And a boiling point 1413C
- They dissolve easily in polar solvents like water
Properties of covalent compounds
They have following properties; How are compounds formed
- They have low melting and boiling points.
- They are bad conducters of electricity.
- They are insoluble in water but are soluble in non aqueous solvents like benzene,ether,alcohol and acetone.
Large molecules with three dimentional bonding form covalent crystals which are very stable and hard.they have very high melting and boiling points. How are compounds formed
Applications of ionic compounds
Uses of sulphuric acid;H2SO4
- It is used in industries for manufacturing of fertilizers.
- It is used for making detergengts.
- It is also used in ppharmasuitical labs for varoius tests.
- It is used in manufacturing of synthetic resins.
- It is used for production of insecticides.
Uses of megnesium hydroxide; Mg(OH)2
- It is used for reducing the acidity of stomach by neutralization reaction. How are compounds formed
- It lised as a lexative , because it is absorbed slowly from intestinal passage that is why it drains water from the surrounding through osmosis.
Uses of potasium nitrate; KNO3
- It is used in fertilizer industry as a source of nitrogen.
- It is used in preserving the food for long time.
- It is used in fireworks and major component of gunpowder acting as an oxidising agent. How are compounds formed
Examples of chemical compounds
- Sodium hypochlorite (NaClO)
- Silver nitrate (AgNO 3 )
- Calcium carbonate (CaCO 3 )
- Copper sulfate (CuSO 4 )
- Potassium permanganate (KMnO 4 )
- Nitric acid (HNO 3 )
- Acetic acid
- Folic acid
- Vitamin D
- Potassium Iodide (KI)
- Calcium superphosphate (Ca (H 2 PO 4 ) 2 )