{"id":993,"date":"2019-10-22T12:54:42","date_gmt":"2019-10-22T12:54:42","guid":{"rendered":"http:\/\/chemdictionary.org\/?p=993"},"modified":"2019-10-22T12:54:49","modified_gmt":"2019-10-22T12:54:49","slug":"dynamic-equilibrium","status":"publish","type":"post","link":"https:\/\/chemdictionary.org\/dynamic-equilibrium\/","title":{"rendered":"Dynamic Equilibrium"},"content":{"rendered":"\n<p>The word equilibrium is derived from the Latin word equilibrium which means \u201c<em>an equal balance\u201d<\/em>. Therefore, we can say that it is a state in which the opposing forces are balanced or a system that is not changing with time i.e. no net force is acting. <\/p>\n\n\n\n<p>Equilibrium is divided into two types: static equilibrium and dynamic equilibrium. A static equilibrium is defined as a state of the body in which the resultant force exerted on an object is zero and the object is stationary.<\/p>\n\n\n\n<p>Dynamic equilibrium is an\nimportant concept of chemistry.it is important to understand how can something\nbe dynamic and at equilibrium at the same time.<\/p>\n\n\n\n<h2><strong>What is a dynamic equilibrium?<\/strong><\/h2>\n\n\n\n<p>Chemical reactions can either\ngo in one direction or both directions i.e. forward and reverse. The forward\nreaction is those that go in one direction while the ones that go in two\ndirections are called reversible reactions. The direction is identified by the\narrows given as follows: <\/p>\n\n\n\n<p>H<sub>2<\/sub>O(l)\n&nbsp;\u21cc H<sup>+<\/sup>(aq) + OH<sup>&#8211;<\/sup>(aq)<\/p>\n\n\n\n<p>Therefore,\nthe dynamic equilibrium can be defined as:<\/p>\n\n\n\n<p>A chemical reaction in which the rate of the reactants is equal to the rate of backward products.<\/p>\n\n\n\n<p>In\nother words,<\/p>\n\n\n\n<p>A reaction is said to be at dynamic equilibrium when the reactants are converted into products and the products are converted to reactants at an equal and constant rate. So the equilibrium is the state of equal and opposite rate but with an unequal concentration.<\/p>\n\n\n\n<p><strong>Explanation\nof dynamic equilibrium:<\/strong><\/p>\n\n\n\n<p>Consider an object is moving at a constant speed that balances all the forces on that object. It will show a dynamic equilibrium when a horizontal force is applied to an object and cause it to move on a horizontal surface with a constant speed. Here the applied force is in the direction of motion while a friction force is produced that is in the opposite direction and balances the applied force-producing no unbalanced force on an object. But as the object is in motion so it continues to move with a constant speed as shown in the figure below: <\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter\"><img loading=\"lazy\" width=\"378\" height=\"214\" src=\"https:\/\/chemdictionary.org\/wp-content\/uploads\/2019\/10\/image-54.png\" alt=\"\" class=\"wp-image-994\" srcset=\"https:\/\/chemdictionary.org\/wp-content\/uploads\/2019\/10\/image-54.png 378w, https:\/\/chemdictionary.org\/wp-content\/uploads\/2019\/10\/image-54-300x170.png 300w\" sizes=\"(max-width: 378px) 100vw, 378px\" title=\"\"><\/figure><\/div>\n\n\n\n<p>Figure\n1.1 showing a wooden piece sliding on a smooth surface<\/p>\n\n\n\n<p><strong>Relationship\nbetween Equilibrium and Rate Constants:<\/strong><\/p>\n\n\n\n<p>Consider the simple reaction\nas follows:<\/p>\n\n\n\n<p>A &nbsp;\u21cc B<\/p>\n\n\n\n<p>Where<\/p>\n\n\n\n<p>A= reactants<\/p>\n\n\n\n<p>B= products<\/p>\n\n\n\n<p>Therefore, the equilibrium constant Keq can be described as:<\/p>\n\n\n\n<p style=\"text-align:center\">K<sub>eq<\/sub>= [B] eq\/ [A] eq<\/p>\n\n\n\n<p>Where <\/p>\n\n\n\n<p>[A]<sub>eq\n<\/sub>= the reactants at equilibrium conditions<\/p>\n\n\n\n<p>[B]<sub>eq\n<\/sub>= the products at equilibrium conditions<\/p>\n\n\n\n<p>Hence, the rate of reaction is given by:<\/p>\n\n\n\n<p style=\"text-align:center\">d[A]\/dt = -kf [A] + kb [B]<\/p>\n\n\n\n<p>Where<\/p>\n\n\n\n<p>Kf=\nthe rate constant for the forward reaction<\/p>\n\n\n\n<p>Kb=\nthe rate constant for the backward reaction<\/p>\n\n\n\n<p>The equilibrium constant can also be calculated by dividing the rate constant of the forward reaction by the rate constant of the reverse reaction:<\/p>\n\n\n\n<p style=\"text-align:center\">Keq = kf\/kb<\/p>\n\n\n\n<p>Where A and B are in equilibrium.<\/p>\n\n\n\n<p><strong>Factors\naffecting an equilibrium:<\/strong><\/p>\n\n\n\n<p>Following are the factors that affect the\nequilibrium:<\/p>\n\n\n\n<ul><li>By changing the concentration of\nreactants or products<\/li><li>By changing the pressure of a gaseous\nequilibrium<\/li><li>By changing the temperature<\/li><\/ul>\n\n\n\n<p><em>Concentration changes:<\/em><\/p>\n\n\n\n<p>If\nthe amount of reactant is increased, the amount of product also increases to\nmaintain an equilibrium. On the other hand, if the amount of reactants\ndecreases, the amount of products also decreases.<\/p>\n\n\n\n<p><strong><em>Concentration\nIncreases<\/em><\/strong><\/p>\n\n\n\n<p>A&nbsp; +&nbsp;\nB&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; \u21cc&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; C&nbsp;\n+&nbsp; D<\/p>\n\n\n\n<p>&nbsp;&nbsp;&nbsp; As the concentration of A increases<\/p>\n\n\n\n<p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; the equilibrium moves to the right<\/p>\n\n\n\n<p><strong><em>Concentration\nDecreases<\/em><\/strong><\/p>\n\n\n\n<p>A&nbsp; +&nbsp;\nB&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; \u21cc&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; C&nbsp;\n+&nbsp; D<\/p>\n\n\n\n<p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; As the concentration of A decreases,<\/p>\n\n\n\n<p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; the equilibrium moves to the left<\/p>\n\n\n\n<p><em>The Pressure Change:<\/em><\/p>\n\n\n\n<p>The\nchange in the direction is dependent on the total number of gas molecules\npresent on each side of the equation. If the pressure is increased there will\nbe an increase in the number of molecules created with the least number of gas\nmolecules available. If the pressure is decreased, there will be an increase in\nthe number of molecules created but at the side with the most number of gas\nmolecules available. <\/p>\n\n\n\n<p><strong>Pressure Increase<\/strong><\/p>\n\n\n\n<p> As the pressure increases, the equilibrium moves to the right.<\/p>\n\n\n\n<p>As the pressure decreases, the equilibrium moves to the left. <\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter\"><img loading=\"lazy\" width=\"327\" height=\"345\" src=\"https:\/\/chemdictionary.org\/wp-content\/uploads\/2019\/10\/image-55.png\" alt=\"\" class=\"wp-image-998\" srcset=\"https:\/\/chemdictionary.org\/wp-content\/uploads\/2019\/10\/image-55.png 327w, https:\/\/chemdictionary.org\/wp-content\/uploads\/2019\/10\/image-55-284x300.png 284w\" sizes=\"(max-width: 327px) 100vw, 327px\" title=\"\"><\/figure><\/div>\n\n\n\n<p><em>Temperature\nchanges:<\/em><\/p>\n\n\n\n<p>If the temperature of the system is\nincreased, the equilibrium will move to bring it down and the reaction will try\nto absorb the heat. If the temperature is decreased, the system will move to\nproduce the heat.<\/p>\n\n\n\n<p><strong>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;Temperature Increase<\/strong><\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter\"><img loading=\"lazy\" width=\"327\" height=\"300\" src=\"https:\/\/chemdictionary.org\/wp-content\/uploads\/2019\/10\/image-56.png\" alt=\"\" class=\"wp-image-999\" srcset=\"https:\/\/chemdictionary.org\/wp-content\/uploads\/2019\/10\/image-56.png 327w, https:\/\/chemdictionary.org\/wp-content\/uploads\/2019\/10\/image-56-300x275.png 300w\" sizes=\"(max-width: 327px) 100vw, 327px\" title=\"\"><\/figure><\/div>\n\n\n\n<p><strong>The\naction of Catalyst:<\/strong><\/p>\n\n\n\n<p>the catalyst will only help to speed up\nthe reaction to reach equilibrium but will not take part in changing the position\nof equilibrium.<\/p>\n\n\n\n<p><strong>Equilibrium\nand Le Chatelier\u2019s Principle:<\/strong><\/p>\n\n\n\n<p>Equilibrium can be described\nby Le Chatelier&#8217;s Principle. The equilibrium position and the kinetics of a\nreaction change depend on the properties of reactants and products. The\nequilibrium transfers towards one side or the other depending on the volume,\nconcentration, pressure, and temperature. Le Chatelier&#8217;s principle can&#8217;t be\nconfused with dynamic equilibrium as they are similar but have distinct\nconcepts. Le Chatelier&#8217;s principle explains how equilibrium can be changed\nwhile dynamic equilibrium describes how an equilibrium behaves.<\/p>\n\n\n\n<h2><strong>Examples\nof Dynamic equilibrium:<\/strong> <strong><\/strong><\/h2>\n\n\n\n<ul><li>Let\u2019s suppose you prepare a saturated\nsolution with sodium chloride, NaCl. Then if you add solid crystals of NaCl,\nthe NaCl will dissolve and recrystallize within the solution at the same time.\nTherefore, the reaction NaCl(s) \u21cc\nNa<sup>+<\/sup>(aq) + Cl<sup>&#8211;<\/sup>(aq), will said to be in dynamic equilibrium\nwhen the rate of dissolution of NaCl will be equal to the rate of\nrecrystallization.<\/li><\/ul>\n\n\n\n<ul><li>If we consider a reaction between\nnitrogen dioxide with carbon monoxide, by attaining dynamic equilibrium it will\ngive nitrogen oxide, NO and carbon dioxide. As it will be in dynamic\nequilibrium, so during its reverse reaction, nitrogen oxide and carbon dioxide\nreact to form nitrogen dioxide and carbon monoxide.<\/li><\/ul>\n\n\n\n<p>NO<sub>2<\/sub>(g) + CO(g) \u21cc NO(g) + CO<sub>2<\/sub>(g)<\/p>\n\n\n\n<ul><li>Dynamic\nequilibrium can also occur in a single-phase system. Let&#8217;s consider an example\nwith acid-base equilibrium such that the dissociation of acetic acid takes\nplace in an aqueous solution as shown below:<\/li><\/ul>\n\n\n\n<p>CH<sub>3<\/sub>CO<sub>2<\/sub>H\n\u21cc CH<sub>3<\/sub>CO<sub>2<\/sub><sup>&#8211;<\/sup>\n+ H<sup>+<\/sup><\/p>\n\n\n\n<p>Here, in this case, some protons will be\nreleased from acetic acid molecules during a forward reaction while the\nbackward reaction tells us the formation of an acetic acid molecule when a\nproton is accepted by an acetate ion. Equilibrium is achieved when the sum of\nreactants on the left side of the equation is equal to the sum of products\npresent on the right-hand side. It means the rate of forwarding and the\nbackward reaction is equal to each other. The formation of the chemical\ncomplexes shows a dynamic equilibrium and the concentrations are rules by the\nstability constants of complexes.<\/p>\n\n\n\n<ul><li>Civil engineers use dynamic equilibrium\nduring the construction of bridges or buildings. They have to consider all the\nforces that will be applied to these structures. They maintain the balance of\nthe structure against the exerted forces by calculating the applied forces and\nthis maintain a state of equilibrium.<\/li><\/ul>\n\n\n\n<ul><li>Dynamic equilibrium plays an important role in\nwarm-blooded species including ourselves. The homeostasis keeps the body\ntemperature constant. When our body gets too hot then our body helps us to cool\nus down by a process of sweating. Sweating allows the heat to escape through\nblood vessels neat to the skin surface to make us feel cool. When our body gets\ntoo cold, we start shivering to generate metabolic heat. This results when\ncapillaries become small in size to retain heat and keeps blood away from arms\nand legs to maintain the core body temperature.<\/li><\/ul>\n\n\n\n<ul><li>Consider\nanother example of a bathtub that is filled with water up to a certain level.\nTake out the plug from the tub and allow the water to keep on adding through a\ntap. The water that is going out of the tub will be equal to the water that is\ncoming into the tub through a tap. Hence we will observe that the amount of\nwater in the tub will remain at a constant level, while there is a fluent\namount of water being added to the tub system. But if we change the system such\nas the flow from either end of the tub, we will observe that the level of the\nwater will also change depending on how much change will occur in the system.<\/li><\/ul>\n\n\n\n<ul><li>In\neconomics the example of the dynamic equilibrium is explained as if you are in\na free market, then according to the theory, the price of a product remains the\nsame. This will be possible only when the buyers will buy all the products that\nthey want and the sellers will sell all they want to sell. If the conditions of\nsupply and demand changes, the prices will either decrease or increase.<\/li><\/ul>\n\n\n\n<p><strong>An Equation that can never be an example\nof dynamic equilibrium:<\/strong><\/p>\n\n\n\n<p>4Fe(s) + 6H<sub>2<\/sub>O(l) + 3O<sub>2<\/sub>(g)&nbsp;changes to&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 4Fe(OH)<sub>3<\/sub> (s)<\/p>\n\n\n\n<p>This\nequation tells us about the formation of rust. We will observe that it will\nnever be in dynamic equilibrium because the arrow goes only in the forward\nreaction that is one way which shows that the rusty object can never come back\nto its original form.<\/p>\n\n\n\n<p><strong>References:<\/strong><\/p>\n\n\n\n<p><a href=\"https:\/\/blog.prepscholar.com\/what-is-dynamic-equilibrium-definition-example\" target=\"_blank\" rel=\"noopener\">https:\/\/blog.prepscholar.com\/what-is-dynamic-equilibrium-definition-example<\/a><\/p>\n\n\n\n<p><a href=\"https:\/\/chem.libretexts.org\/Bookshelves\/Physical_and_Theoretical_Chemistry_Textbook_Maps\/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)\/Equilibria\/Chemical_Equilibria\/Principles_of_Chemical_Equilibria\/Dynamic_equilibrium\" target=\"_blank\" rel=\"noopener\">https:\/\/chem.libretexts.org\/Bookshelves\/Physical_and_Theoretical_Chemistry_Textbook_Maps\/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)\/Equilibria\/Chemical_Equilibria\/Principles_of_Chemical_Equilibria\/Dynamic_equilibrium<\/a><\/p>\n\n\n\n<p><a href=\"https:\/\/anotherequilibriumsite.weebly.com\/everyday-examples.html\" target=\"_blank\" rel=\"noopener\">https:\/\/anotherequilibriumsite.weebly.com\/everyday-examples.html<\/a><\/p>\n\n\n\n<p><a href=\"https:\/\/www.thoughtco.com\/definition-of-dynamic-equilibrium-605052\" target=\"_blank\" rel=\"noopener\">https:\/\/www.thoughtco.com\/definition-of-dynamic-equilibrium-605052<\/a><\/p>\n\n\n\n<p><a href=\"https:\/\/blog.prepscholar.com\/what-is-dynamic-equilibrium-definition-example\" target=\"_blank\" rel=\"noopener\">https:\/\/blog.prepscholar.com\/what-is-dynamic-equilibrium-definition-example<\/a><\/p>\n\n\n\n<p><a href=\"https:\/\/biologydictionary.net\/dynamic-equilibrium\/\" target=\"_blank\" rel=\"noopener\">https:\/\/biologydictionary.net\/dynamic-equilibrium\/<\/a><\/p>\n\n\n\n<p><a href=\"https:\/\/en.wikipedia.org\/wiki\/Dynamic_equilibrium\" target=\"_blank\" rel=\"noopener\">https:\/\/en.wikipedia.org\/wiki\/Dynamic_equilibrium<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>The word equilibrium is derived from the Latin word equilibrium which means \u201can equal balance\u201d. Therefore, we can say that it is a state in which the opposing forces are balanced or a system that is not changing with time i.e. no net force is acting. Equilibrium is divided into two types: static equilibrium and &#8230; <a title=\"Dynamic Equilibrium\" class=\"read-more\" href=\"https:\/\/chemdictionary.org\/dynamic-equilibrium\/\" aria-label=\"More on Dynamic Equilibrium\">Read more<\/a><\/p>\n","protected":false},"author":6,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"rating_form_position":"","rating_results_position":"","mr_structured_data_type":""},"categories":[3,2],"tags":[],"multi-rating":{"mr_rating_results":[{"adjusted_star_result":5,"star_result":5,"total_max_option_value":5,"adjusted_score_result":5,"score_result":5,"percentage_result":100,"adjusted_percentage_result":100,"count":1,"post_id":993}]},"_links":{"self":[{"href":"https:\/\/chemdictionary.org\/wp-json\/wp\/v2\/posts\/993"}],"collection":[{"href":"https:\/\/chemdictionary.org\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/chemdictionary.org\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/chemdictionary.org\/wp-json\/wp\/v2\/users\/6"}],"replies":[{"embeddable":true,"href":"https:\/\/chemdictionary.org\/wp-json\/wp\/v2\/comments?post=993"}],"version-history":[{"count":5,"href":"https:\/\/chemdictionary.org\/wp-json\/wp\/v2\/posts\/993\/revisions"}],"predecessor-version":[{"id":1039,"href":"https:\/\/chemdictionary.org\/wp-json\/wp\/v2\/posts\/993\/revisions\/1039"}],"wp:attachment":[{"href":"https:\/\/chemdictionary.org\/wp-json\/wp\/v2\/media?parent=993"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/chemdictionary.org\/wp-json\/wp\/v2\/categories?post=993"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/chemdictionary.org\/wp-json\/wp\/v2\/tags?post=993"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}