The terms endergonic and exergonic are used to explain two types of chemical reactions. An endergonic reaction is a non-spontaneous reaction. It does not occur in normal conditions such as at room temperature and atmospheric pressure. An exergonic reaction is the opposite of endergonic reaction. An exergonic reaction is a spontaneous reaction. It occurs at normal conditions without any external force. Each and every chemical reaction can be categorized as an endergonic reaction or an exergonic reaction. The main difference between endergonic and exergonic is that endergonic reaction requires energy from the outside whereas exergonic reactions release energy to the outside. Show
Key Areas Covered1. What is
Endergonic Key Terms: Endergonic, Enthalpy, Entropy, Exergonic, Gibbs Free Energy, Spontaneous Reaction What is EndergonicEndergonic is a type of reaction that has a positive Gibbs free energy. The Gibbs free energy is a thermodynamic potential that is used to predict whether a chemical reaction is spontaneous or non-spontaneous. A negative Gibbs free energy indicates a spontaneous reaction. In case of endergonic reactions, the Gibbs free energy is a positive value, which indicates it is a no-spontaneous reaction. Non-spontaneous reactions can also be named as unfavorable reactions. The Gibbs free energy of endergonic reaction is a positive value when calculated using the following thermodynamic relationship. ΔG = ΔH – TΔS Where, ΔG is the Gibbs free energy ΔH is the change in enthalpy T is the temperature of the system ΔS is the change in entropy. Figure 1: Energy Diagram for an Endergonic Reaction In a non-spontaneous reaction, energy should be provided from outside for the progression of the reaction. Then, the energy of the products gets a higher value than that of the energy of the reactants. Due to that reason, the change in enthalpy is a positive value (the change in the enthalpy is the difference between the enthalpies of products and reactants). Since new products are formed, the entropy of the system is decreased. Then, according to the above equation, the ΔG is a positive value. Endergonic reactions include endothermic reactions. What is ExergonicExergonic is a type of reaction that has a negative Gibbs free energy. This indicates that an exergonic reaction is a spontaneous reaction since spontaneous reactions have a negative value for Gibbs energy when calculated using the thermodynamic relationship given below. ΔG = ΔH – TΔS Figure 1: Energy Diagram for an Exgorgenic Reaction In exergonic reactions, energy is released to the surrounding. Therefore, the products have a lower energy than that of the reactants. Due to that reason, the change in enthalpy is a negative value for exergonic reactions. The entropy is increased due to the disorder of the system. According to the above relationship, the Gibbs free energy is a negative value. Exergonic reactions include exothermic reactions. Difference Between Endergonic and ExergonicDefinitionEndergonic: Endergonic is a type of reaction that has a positive Gibbs free energy. Exergonic: Exergonic is a type of reaction that has a negative Gibbs free energy. Gibbs Free EnergyEndergonic:The Gibbs free energy is a positive value for endergonic reactions. Exergonic:The Gibbs free energy is a negative value for exergonic reactions. Energy of Reactants and ProductsEndergonic:In endergonic reactions, the energy of reactants is lower than that of the products. Exergonic:In exergonic reactions, the energy of reactants is higher than that of the products. EntropyEndergonic:The entropy is decreased in endergonic reactions. Exergonic:The entropy is increased in exergonic reactions. NatureEndergonic: Endergonic reactions are non-spontaneous. Exergonic: Exergonic reactions are spontaneous. ExamplesEndergonic: Endothermic reactions are endergonic reactions. Exergonic:Exothermic reactions are exergonic reactions. Beginning of the ReactionEndergonic: Endergonic reactions always require energy to begin the reaction. Exergonic:Exergonic reactions do not need energy to begin the reaction. Energy ExchangeEndergonic:Endergonic reactions absorb energy from the surrounding. Exergonic: Exergonic reactions release energy to the surrounding. ConclusionAll chemical reactions that happen in our surrounding can be categorized as either endergonic reaction or exergonic reactions. These two types of reactions have opposite definitions and properties. The main difference between endergonic and exergonic is that endergonic reaction requires energy from outside whereas exergonic reactions release energy to the outside. References:1. “Endergonic Reaction: Definition & Examples.” Study.com, Available here. Accessed 21 Sept. 2017. Image Courtesy:1.”Endergonic” By J3hoang – Own work (CC BY-SA 3.0) via
Commons Wikimedia What is exergonic reaction with example?Exergonic reactions occur spontaneously (no outside energy is required to start them). Examples of exergonic reactions include exothermic reactions, such as mixing sodium and chlorine to make table salt, combustion, and chemiluminescence (light is the energy that is released).
What is endergonic reaction example?An endergonic reaction is one that requires free energy to proceed. An example of an endergonic reaction of biological interest is photosynthesis. Photosynthetic organisms conduct this reaction by using solar photons to drive the reduction of carbon dioxide to glucose and the oxidation of water to oxygen.
What are exergonic reactions?An exergonic reaction refers to a reaction where energy is released. Because the reactants lose energy (G decreases), Gibbs free energy (ΔG) is negative under constant temperature and pressure. These reactions usually do not require energy to proceed, and therefore occur spontaneously.
What is the difference between an exergonic and endergonic reaction?In the exergonic reaction, the reactants are at a higher free energy level than the products (reaction goes energetically downhill). In the endergonic reaction reaction, the reactants are at a lower free energy level than the products (reaction goes energetically uphill).
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