CHEMISTRY

Sulphur  is a chemical element. It has symbol  S. Atomic number of Sulphur= 16 Atomic mass of Sulphur= 32 Electronic configuration = 1s 2 2s 2 2p 6 3s 2 3p 4 Under normal conditions, sulphur atoms form cyclic octatomic molecules with the chemical formula  S 8 .  Sulphur is a bright yellow, crystalline solid at room temperature. It makes up about 0.1% of the earth crust. It is widely found in combined state as sulphide of iron, zinc, lead, copper and mercury. It is also found in some proteins.                   Extraction of Sulphur Most of the world's sulphur is obtained from the underground deposits. The process involved in the extraction of Sulphur from the underground is known as FRASCH PROCESS.                  Allotropes of Sulphur  Allotrope is the ability of an element to exist in two or more different forms in the same...

Organic chemistry is defined as the chemistry of carbon compounds. Apart from the main element, carbon, organic compounds may contain hydrogen, oxygen, and sometimes nitrogen, halogens, phosphorus, and sulphur. Organic compounds are covalent.                           Catenation  Catenation is the combination of the atoms of an element to form straight, branched, or ring-chain compounds. Examples of elements that can catenate include carbon, silicon, boron, and sulphur.            Hybridization in a carbon atom Hybridization is the mixing of two or more orbitals of the same principal quantum number to give new sets of orbitals that are exactly equivalent. The new orbitals are known as hybrid orbitals.                Hybridization of carbon                         ...

Hydrocarbons are organic compounds containing hydrogen and carbon only. All hydrocarbons have the general molecular formula of C x H y Examples of hydrocarbons include methane[ CH 4 ], ethene[C 2 H 4 ], ethyl[ C 2 H 2 ], benzene[ C 6 H 6 ], etc  Hydrocarbons are classified into two main groups according to their structure. 1. Aliphatic hydrocarbons  2. Aromatic hydrocarbons                  Sources of hydrocarbons  The natural sources of hydrocarbons are: 1. Natural gas 2. Crude oil (Petroleum) 3. Coal They are known as fossil fuels. •Natural gas is a gaseous fuel •Petroleum is a dark viscous liquid fuel •Coal is a solid fuel                  Crude oil (Petroleum) Crude oil  is a dark and sticky viscous liquid found in the underground. It contains hydrocarbons such as alkanes, alkenes, etc.  Natural gas  is found t...

Chlorine is the most important element in the halogen family. It does not occur as a free element in nature because it is too reactive. It is usually found in the combined state as chlorides e.g. NaCl. Which is found in the sea and as salt deposits. Atomic mass =35.5  Atomic number = 17  Electronic configuration= 1s 2 2s 2 2p 6 3s 2 3p 5  OR [Ne]3s 2 3p 5           Electronic shell configuration  The nucleus contains 17   protons   and 18 neutrons  There are two stable isotopes of chlorine. They are  37 Cl  and  35 Cl. Chlorine has a naturally occurring radioactive isotope, the cosmogenic isotope,  36 Cl . A Swedish chemist, Carl Wilhelm Scheele, discovered chlorine in 1774. A.  Laboratory preparation of chlorine   The laboratory method for the preparation of chlorine: 1. Using manganese (IV) oxide. Heat a mixture of Manganese(IV) oxide and concentrated HCl. T...

                      Chemical Industry The chemical industry is an industry that applies chemical processes to convert raw materials into useful chemical products.                   Important Raw Materials The major raw materials used in the chemical industry include: 1. Petroleum 2. Natural gas 3. Coal 4. Air 5. Seawater 6. Limestone 7. Metallic ores (e.g., iron ore) 8. Sulphur 9. Rock salt                  Heavy and Fine Chemicals A. Heavy Chemicals Heavy chemicals are substances produced in large quantities and widely used in industrial processes. Examples of heavy chemicals include: 1. Tetraoxosulphate (VI) acid (H₂SO₄) 2. Hydrochloric acid (HCl) 3. Trioxonitrate (V) acid (HNO₃) 4. Calcium trioxocarbonate (IV) (CaCO₃) 5. Caustic soda (NaOH) 6. Slaked lime (Ca(OH)₂) 7. Metals (e.g., iron, copper, tin, aluminium, zinc) 8. Bleachi...

Chemical formula:  This is the formula that shows the elements in a particular chemical substance and the number of each atom present Types of Chemical Formula There are three basic types of chemical formula:  1.  Empirical formula  2.  Molecular formula  3.  Structural formula  1. Empirical formula: This is the chemical formula that gives the simplest whole number ratio of atoms present in a compound. 2. Molecular formula: This is the  chemical formula that gives the total number of atoms of each element in each molecule of a compound. 3. Structural formula: This is the chemical formula that shows the location of chemical bonds between the atoms of a molecule.       The structural formula of methane The chemical formula of some compounds: 1.   Sodium hydroxide: NaOH  2. Potassium hydroxide: KOH  3. Calcium hydroxide:  Ca(OH)₂ 4. Sodium c...