CHEMISTRY

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...

A chemical equation  is a symbolic representation of a chemical reaction showing the reactants and products. An example of a chemical equation is the reaction between hydrogen and oxygen to form water.              2H 2(g)  + O 2(g)  → 2H 2 O (g)               Reactant             Product  The  reactant side  is the part of the chemical equation to the left of the ‘→’ symbol whereas the  product side  is the part to the right of the arrow symbol. Examples: Balance the following reactions 1. Al + O 2  → Al 2 O 3 2.  N 2  + H 2  → NH 3 Solution:   1. 4 Al + 3 O 2  → 2 Al 2 O 3.  2.  N 2  + 3 H 2  → 2 NH 3.     React and balance the following: 1.  FeCl 3(s)  + NaOH → 2.  FeSO 4  + NaOH → 3.  Zn + HCl → 4....

                                Extraction of iron Extraction of iron is the process of removing iron from its ore.                             Ore An ore is a naturally occurring rock or mineral that contains a useful metal in sufficient quantity. e.g. Iron ore. The most common iron ore is haematite (Fe₂O₃).                    OCCURRENCE Iron occurs naturally as ores. The common iron ores are: 1. Haematite (Fe 2 O 3 ) 2. Magnetite (Fe 3 O 4 ) 3. Iron pyrite (FeS 2 ) 4. Siderite (FeCO 3 ) 5. Limonite( Fe 2 O 3 .H 2 O) Iron is the second most abundant metal found in the earth's crust after aluminium. It is also present in clay soil, hemoglobin in animals, and chlorophyll in plants.                    EXTRACTION OF IRON The ra...

Molar mass is the mass of one mole of a chemical substance. The S.I.unit of molar mass is g/mol  Examples : Calculate the molar mass of the following: 1. Water (H 2 O) 2. Table salt (NaCl) 3. Calcium oxide (CaO) 4. Calcium carbonate (CaCO 3 )    [H=1, O=16, Na=23, Cl=35.5, C=12, Ca=40] Solution:  1. H 2 O= 2(1) + 16              = 18g/mol  2. NaCl= 23 +35.5               =58.5g/mol  3. CaO= 40+16              =56g /mol  4. CaCO 3  = 40+12+3(16)                    =52+48                    =100g/mol                    NUMBER OF ATOMS Calculate the number of atoms in each of the following: 1. H 2 O 2. Three moles of  H 2 O 3. NaOH  4. Two moles of NaOH...

                       SEPARATION TECHNIQUES Separation techniques are physical methods used for the separation of the constituents of a mixture.        Types of Separation techniques  The types   of separation techniques are:  1. Sieving 2. Filtration  3. Sublimation  4. Decantation  5. Separating funnel  6. Evaporation  7. Chromatography 8. Magnetic separation 9. Distillation  10. Fractional distillation  11. Centrifugation 12. Crystallization  13. Fractional crystallization Sieving is used to separate solid particles of different sizes. Particles smaller than the size of the sieve (mesh) pass through leaving behind particles of larger sizes. It is used in gold and diamond mines and garri industries. This method is used to separate insoluble solids from liquids using a filter. For example, a mi...

                                         ALLOY An alloy is a substance formed from the combination of two or more elements, with at least one of which is a metal. Examples of alloys and their components:   Reasons why alloys are made Alloys are made to: 1. To increase strength of the material  2. To improve resistance to corrosion 3. To enhance appearance               Properties of Alloys 1. Alloys are stronger than pure metals 2. They are more durable 3. They are resistant to rust and corrosion 4. They are sometimes more attractive                        Uses of alloy  1. Brass: for making nuts, bolts, rods, musical instruments, etc  2. Bronze:  for making medals, coins, sculptures, etc 3. Steel:  for making household fittings s...

                                                    Rusting   Rusting  is also known as corrosion of iron. It is defined as the  interaction of Iron with air and water to produce rust When iron is exposed to air and moisture, its surface gradually corrodes and converts into a brown mass. This brown mass is called rust and this phenomenon is known as rusting.          Conditions for rusting of iron  1. Presence of water (moisture) 2. Presence of air (Oxygen) The corrosion of metals results from the combined action of atmospheric oxygen and water. The most important example of metallic corrosion is that of iron. The iron reacts with water and oxygen to form hydrated iron(III) oxide, [Fe₂O₃] which we see as rust.                   Effects of Rusting 1. Rusting ...

Petrochemicals are substances that are manufactured from the by-products of petroleum.            Petrochemical products  Products made from petrochemicals include the following items: 1. Plastics  2. Fertilizers  3. Detergents  4. Pesticides  5. Drugs  6. Cosmetics  7. Food additives  8. Paints  9. Textile materials  10. Synthetic rubber etc             The importance of crude oil and petrochemicals: 1.  Provision of employment  2. Sources of revenue for individuals and country  3. Sources of energy  4. Provision of raw materials for the industry                Petrochemical products

Write the chemical formula of the following compounds: 1. Carbon (II) oxide (Valency: C=2, O=2) 2. Carbon (IV) oxide: (Valency: C=4, O=2) 3. Sulphur (II) oxide: (Valency: S=2, O=2) 4. Sulphur (IV) oxide: (Valency: S=4, O=2) 5. Ammonia: (Valency: N=3, H=1) 6. Ammonium: (Valency: N=4, H=1) 7. Methane: (Valency: C=4, H=1) 8. Calcium oxide(Quicklime): (Valency: Ca=2, O=2) 9. Water: (Valency: H=1, O=2) 10. Hydrochloric acid: (Valency: H=1, Cl=1)