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Heat Of Reaction

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Fig:- Reaction Energy Diagram   In the above figure, this enthalpy change in energy between reactants and products is called " Heat Of Reaction ".  The value of the heat of reaction determines whether the reaction is exothermic or endothermic. Besides activation and threshold energy, another form of energy exists here and that is " Heat Of Reaction ". It is also known as " Enthalpy Change ". It is defined as the net amount of energy that should be added or released during a chemical reaction. Figure-1 Figure-2 In the above figure, energy of the reactants and the energy of the products are not the same, but there are some differences between them. And this difference represents the heat of the reaction.  Hence, " Heat  of a reaction is defined as the difference between the average energy of the reactants and the average energy of the products ".  This difference can be positive or negative. And depending on these positive and negative values of th

Activation Energy Vs Threshold Energy

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We all must have heard about " Threshold Energy " and " Activation Energy ". So let us now see the difference between threshold energy and activation energy.  From ' Collision Theory ', we know that a reaction occurs when the reactant molecules collide with each other and these collisions must be an effective collision so that the reaction can occur. The collision are an effective collision if the reactant molecules must have energy more than threshold energy. Reactant molecules have low energy at room temperature due to which their collisions are not effective and reactants do not convert into products. In this situation, we give energy (or activation energy) to reactant molecules in the form of heat, light etc. So that they absorbs this energy and their energy becomes equal to or greater than threshold energy. As a result, the reactant is easily converted into products by effective collisions.   Thus, " Threshold energy is the summation of the avera

Activation Energy: Minimum Amount Of Energy

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When a reaction goes to completion then the reactant present in the reaction is converted into product by passing through the activated state (or the highest energy level in the reaction energy diagram). And to overcome this activated state (which is the highest energy point in the reaction energy diagram), reactant molecules must have enough energy so that they can be easily converted into products and that much amount of energy required by the reactant molecules to overcome this activated state is called as " Activation Energy ". Thus, activation energy is the minimum amount of energy needed to start a chemical reaction. Thus, we can define the activation energy as; " Activation Energy is the least possible amount of energy required by the reactant molecules to start a chemical reaction ". And activation energy is usually expressed in calories or joules per mole. For Example Burning of woods using lighter. Here, the energy given off by the lighter is nothing but t

Factors Affecting The Rate Of Reaction

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" Chemical Kinetics " also known as " Reaction Kinetics " which helps us to understand the rate of chemical reactions (or reaction rate) and tells us how these rates influenced by certain conditions.  For Examples :  Some reactions are happened at a faster rate (like in few second) while others are happened at a very slow rate (like in many days).  Rusting of iron - At a slow rate Wood combustion - At a fast rate  Nuclear explosion- At a fast rate Hence, the rate of reaction (at which a reaction goes to completion) can change according to the condition through which the reaction occurs.   In this article, we will learn about the factors which affects the rate of reaction . Rate Law Let us define a " Rate Law " which tell us about the rate of reaction and also tell us that these rates are affected by which parameters, " A rate law or a rate equation is a relationship between the reaction rate and the concentration of its reactants ". Thus, a reac