It is a well known fact that energy menifests itself in different forms which are interconvertible into one another. Among different forms of energy, the electrical energy plays a very significant role in our daily life. Many chemical transformations and industrial processes are based on electrical energy and its relationship with chemical energy. There are […]
The passage of electricity through the electrolytes in their molten or dissolved state can cause chemical changes under suitable conditions. For example, the passage of electricity through the acidified water results in the formation of hydrogen and oxygen gases. The process of chemical decomposition of the electrolyte by he passage of electricity through its molten
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When an electric current is passed through an electrolyte solution, the ions of the electrolyte undergo chemical changes at the respective electrodes. The chemical reaction carried out by passing electricity is called electrolysis. it is important that we familiarize ourselves with different terms that we are going to use to explain different phenomena. It is
IONIC THEORY To account for the phenomena of electrolysis the Ionic Theory was put forward by Arrhenius in 1880. The theory states that electrolytes are made up of ions, which are built up in certain patterns called crystal lattice. When these substances dissolve in water, the structure is destroyed and the ions are set free
Balancing by Ion Electron or Half Reaction Method We are familiar with the balancing of chemical equations by inspection method. However, inspection method may not be useful for balancing the redox equations because in these equations, we have to keep in mind the conservation of charge as well as conservation of mass. The redox equations,
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Most of the properties of the elements such as atomic volume, atomic size, ionization enthalpy, electron affinity and electronegativity are directly related to the electronic configuration of the atoms. These properties undergo periodic variation with the change in the atomic number within a period or a group. These properties indirectly control the physical properties such
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THE NEED FOR CLASSIFICATION OF ELEMENTS Before the beginning of eighteenth century, only a very few elements were known and it was quite easy to study and remember their individual properties. In 1800, only 31 elements were known. This number of elements grew to 63 by 1865. With the discovery of large number of elements
AMINES It has a functional group of NH2. GENERAL MOLECULAR FORMULAR/STRUCTURE It has a general molecular formula of RNH2 or structure of R – N – H H PREPARATION: They are derivatives of ammonia where one or more hydrogen atoms have been replaced by alkyl or aryl groups e.g. RNHz, R2NH. CLASSIFICATION: Amines can
Carbohydrates are naturally occurring organic compounds containing carbon, hydrogen and oxygenwith oxygen in the ratio 1:2 as in water. The general molelcular formula of carbohydrates is Cx(H2O)y or CxH2yOy. Carbohydrates are generally polydroxyl aldehydes, ketones or any compound that on hydrolysis yields any of the polyhydroxides. They are synthesized in green plants by photosynthesis.
NATURAL AND SYNTHETIC POLYMERS Polymerisation (addition and condensation) plastics. Thermosplastic and thermosetting polymers, resins. Polymer is the final product, macromolecule of high molecular mars. It consists of a repeating units and its general molecular formula may be represented as [repeating units]n where n is a very large whole number. N.B:- All polymers are
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Sources, properties and uses detergents and soaps Structure, their mode and action. Fats and oils belong to a general group of compounds known as lipids. SOURCES Fats are solids that usually come from animals e.g. Tallow (mutton fat). Oils are liquids that come from plants e.g. vegetable oil, coconut oil etc. Both fat and oil
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ALKANOATES General molecular formula, nomenclature, preparation, properties and uses. SOURCES The alkanoic acid or carboxylic acids are also called fatty acids because some of them are found in natural fats and oils. They contain the functional group called carboxy group. NOMENCLATURE The IUPAC name of each homologue is obtained by changing the “-e”
SOURCES OF ALKANOLS – From destructive distillation wood. – From starchy food and sugar General molecular formular Alkanol is a homologous series with general molecular formular of Cn H2n+1OH or ROH. Or (CnH2n+2O). Nomenclature The names of alkanols are obtained by substituting “e” in alkanes with “Ol” in alkanol e.g. methanol (CH3OH), ethanol
Benzene: Benzene is a typical aromatic compound with molecular formula of C6H6. It has the structure of: Preparation From coal tar: The destructive distillation of coal produced coal tar which contain benzene From petreoleum; The dehydrogenated of alkane using valladim (v) oxide (v2O5) as catalyst at 500oC and 20 atmos give benzene C6H14 V2O2C6H6 +
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Alkynes are the homologous series of unsaturated hydrocarbon with a general molecular formua CnH2n-2. Alkynes show a high degree of unsaturation than alkenes, hence,t hey are chemically more reactive than the corresponding alkenes or alkanes. Examples are : H H – C = C – H HC – C = C- H [ Ethyne.
UNSATURATED HYDROCARBONS These are hydrocarbons in which carbon atoms join with each other by multiple bonds. The multiple bond can be double bonds e.g Alkene or triple bonds e.g Alkyne. Ethene2 .Ethyne H – C = C – H H – C = C – H H H. Alkenes e.gEthene Nomenclature The process of naming
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Saturated Hydrocarbons Saturated hydrocarbons are hydrocarbons consisting of carbon chains with single bond between them in which carbon joins with another carbon by single covalent bond e.g Alkanes ( like ethane C2H6, propane C3H8 ) H H HHH H – C C – H H – C – C – C – H
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Percentage of Oxygen in Air We have read that Air consists mainly of molecules of oxygen and nitrogen with important yet trace amounts of other gases. We know that the combustion of organic material requires oxygen. The idea here is to capture a quantity of air in a measured and isolated volume and then use
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Alkali is pronounced like alcohol, with ‘lie’ at the end instead of ‘hol’. An alkali is any substance which produces OH– ions in water. OH– ions are called hydroxide ions. If there are excess of (OH)– ions when a compound is dissolved in water, the solution is called a base or an alkaline solution. A base
WHAT IS ACIDS, BASES AND INDICATORS? All the elements in nature fall into three classes: metals, non-metals and gases. Non-metals are also sometimes called metalloids. The compounds formed by combination of the elements can also be classified as organic and inorganic compounds. Organic compounds are formed from a combination of carbon and hydrogen; they are
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