Dictionary, Defintion, Meaning, What is Endothermic Reaction, Entropy, Enols, Enrichment, Entrainment, Enzyme, End Point, Enamels, Vitreous Enamel

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Home >> Chemistry Dictionary >>Endothermic Reaction - Entropy

Your Ad Here	Emulsion. A colloid in which small particles of one liquid are dispersed in another liquid. Usually emulsions involve a dispersion of water in an oil or a dispersion oil in water and are stabilized by an emulsifier. Commonly emulsifiers are substances, such as detergents, that have lyophobic and lyophilic parts in their molecules. Enamels, Vitreous Enamel. A glassy coating fused to metal at high temperatures, acting as a protective and decorative surface. Enantiomers. Isomers differing in their configuration at a chiral atom.
Enantiotropic. Describes crystalline forms of a substance that can undergo a reversible change at a transition point. Enantiotropy. The reversible transformation of one form or one allotrope into another at a definite transition temperature, e.g., red Hgl² -----> yellow Hgl² and 126°C. Endothermic reaction. A reaction in which heat is absorbed. According to the laws of thermodynamics a spontaneous endothermic reaction must be accompanied by an increase in entropy of the system and surroundings.
End Point. The point in a titration at which reaction is complete as shown by the indicator. End product. Each radioactive series finally forms a stable non-radioactive element, which is the end product, in each case an isotope of lead. Enediols. Organic compounds containing one carbon – carbon double bond and two hydroxyl groups.	Your Ad Here
Energy. A measure of a system’s ability to do work. Life work, itself, it is measured in joules. Energy is conveniently classified into two forms; potential energy is the energy stored in a body or system as a consequence of its position shape, or state (this includes gravitational energy, electrical energy, nuclear energy, and chemical energy); kinetic energy is energy of motion and is usually defined as the work that will be done by the body possessing the energy when it is brought to rest. For a body of mass m having speed v, the kinetic energy is mv2/2. The rotational kinetic energy of a body having an angular velocity w is Iw2/2, where I is its moment of inertia. The internal energy of a body is the some of the potential energy and the kinetic energy of its component atoms and molecules.
Your Ad Here	Energy levels. Energy is taken up by a molecule, (say by the absorption of light), may cause an electronic transition; it may increase the energy of rotation of the molecule as a whole, or may increase the energy of vibration of the nuclei of the constituent atoms relative to one another. The changes all occur in accordance with the quantum hypothesis, i.e., the changes in energy are not continuous, but take place only in definite steps. Thus, every electronic orbital is associated with specific energy value, or energy level. So the rotational and vibrational states have only certain restricted energy values, or energy levels. Digrammatically, there are usually represented as a series of horizontal, parallel straight lines separated by distances proportional to the differences in energy of the various states.

Enols. Compounds having the group – CH = C(OH)- in their molecules.

Enrichment. The term used for the process of increasing the abundance of a specified isotope in a mixture of isotope.

Entrainment. The carrying forward by a stream or gas or vapour of fine liquid droplets.

Entropy. (s) A thermodynamic quantity which is a measure of the degree of disorder within any system. The greater the degree of disorder the higher the entropy. Thus, for a given substance
S gas > S liquid > S solids
Any change taking place which results in an increase in entropy has a positive entropy changes (D S). Most spontaneous thermodynamic processes are accompanied by an increase in entropy. Entropy has units of joules per degree K per mole.

Enzyme. A protein that acts as a catalyst in biochemical reactions. Each enzyme is specific to a particular reaction or group of similar reactions. Many require the association of certain nonprotein cofactors in order to function.
The molecule undergoing reaction (the substrate) binds to a specific active site on the enzyme molecule to from a shortlived intermediate: this greatly increases (by a factor of up to 1020) the rate at which the reaction proceeds to form the product. Enzyme activity is influenced by substrate concentration and by temperature and pH, which must lie within a reaction range. Other molecules may complete for the active site, causing inhibition of the enzyme or even irreversible destruction of its catalytic properties.
The names of most enzymes end in ase, which is added to the names of the substrates on which they act. Thus lactase is the enzyme that acts to break down lactose.

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Dictionary of Chemistry - Part 3 Part 4 Dilatometer - Dipole Moment Dispersing Agent - Doping Dulong Petit's Law - Dysprosium Ebonite - Einstein Equation Electrolysis - Electron Diffraction Electrophoresis - Emulsifying Agent Endothermic Reaction - Entropy Epimerism - Equilibrium Ergosterol - Esterification Ethene (ethylene) - Ethylation Eudiometer - Explosion Flavin Adenine Dinucleotide - Fehling's Solution Fenton's Reagent - Fibre Reactive Dyestuffs Fireclay - Flame Emission Spectroscopy Fluorescein - Fluorocarbons Fractional Crystallisation - Freeze Drying Fullers Earth - Fusible Alloys Gabriel's Reaction - Gas Calorimeter Gay Lussac's Law - Germanates Glass Electrode - Glyoxal

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