Wow nice, by visualizing this, I think I perfectly understand chemical equilibrium 

How is equilibrum constant of forward reactiom equals to reverse reaction.

<div>
<h2 class="title">Chemical equilibrium</h2>
<p>Systems in equilibrium are balanced. For example, if you are running on a treadmill you are in constant motion. However, you are not moving forward or backwards. As fast as you run forward the treadmill is moving you backwards. You are in equilibrium with the treadmill.</p>
<img alt="" src="https://data.ulearngo.com/assets/f2cca798-e4b5-4bec-b67f-b2810f788582"/>
<p>In the same way chemical reactions can be in equilibrium (the products and reactants are produced at the same rate). We will begin by exploring chemical equilibrium in more detail. Ways of measuring equilibrium and the factors that affect equilibrium will be covered.</p>
<section>
<h2 class="title">What is chemical equilibrium?</h2>
<p>To define chemical equilibrium we need to ask some important questions about reactions:</p>
<ol>
<li>
<p>Does a reaction always run its full course so that all the reactants are used up?</p>
<ul>
<li>When all the reactants in a reaction are used up the reaction is said to have <strong>gone to completion</strong>. However, in some reactions not all the reactants are used. \(\color{red}{\textbf{Not all reactions go to completion}}\).</li>
</ul>
</li>
<li>
<p>Does a reaction always proceed in the same direction or can it be reversed? In other words, does a reaction always proceed <em>reactants \(\to\) products</em>, or is it possible that a reaction will reverse and go <em>products \(\to\) reactants</em>?</p>
<ul>
<li>Reactions that go to completion are <em>irreversible</em>. However, in some reactions the reactants form products (in a \(\color{red}{\textbf{forward reaction}}\)), and the products can change back into reactants (in a \(\color{red}{\textbf{reverse reaction}}\)).</li>
</ul>
</li>
<li>
<p>Can a reaction reach a point where reactants are still present, but there does not seem to be any further change taking place in the reaction?</p>
<ul>
<li>
<p>In all reactions, as the amount of reactant in a reaction decreases the product is formed more slowly. In a reversible reaction, as the amount of product increases the reactant is formed more quickly. Eventually the rate of the forward reaction (reactants \(\to\) products) equals the rate of the reverse reaction (products \(\to\) reactants).</p>
<p>At this point there \(\color{red}{\textbf{are still reactants present}}\) but there does not <em>appear</em> to be any further change taking place. The reaction is said to be in \(\color{blue}{\textbf{chemical}}\) \(\color{blue}{\textbf{equilibrium}}\).</p>
</li>
</ul>
</li>
</ol>
<p>Chemical equilibrium is the state of a <a data-lesson="reversible-reactions" data-subject="chemistry" data-tutorial="chemical-equilibrium" href="https://app.ulearngo.com/chemistry/chemical-equilibrium/reversible-reactions">reversible reaction</a> where the rate of the forward reaction equals the rate of the reverse reaction. While a reaction is in equilibrium the <a data-lesson="equilibrium-calculations" data-subject="chemistry" data-tutorial="basic-equilibrium-concepts" href="https://app.ulearngo.com/chemistry/basic-equilibrium-concepts/equilibrium-calculations">concentration</a> of the reactants and products are constant.</p>
<div class="ns-school-emp">
<h3>Definition: Chemical equilibrium</h3>
<div class="ns-school-defn">
<p>A reaction is in chemical equilibrium when the rate of the forward reaction equals the rate of the reverse reaction.</p>
</div>
</div>
<p>There are many examples of chemical equilibrium all around you. One example is a bottle of fizzy cooldrink. In the bottle there is <a data-lesson="carbon" data-subject="chemistry" data-tutorial="metals-metalloids-nonmetals" href="https://app.ulearngo.com/chemistry/metals-metalloids-nonmetals/carbon">carbon</a> dioxide (\(\text{CO}_{2}\)) dissolved in the liquid. There is also \(\text{CO}_{2}\) gas in the space between the liquid and the cap. There is a constant movement of \(\text{CO}_{2}\) from the liquid to the gas phase, and from the gas phase into the liquid. However, if you look at the bottle there does not appear to be any change. The system is in equilibrium.</p>
<p>\(\text{CO}_{2}(\text{g}) + \text{H}_{2}\text{O}(\text{l})\) \(\rightleftharpoons\) \(\text{H}_{2}\text{CO}_{3}(\text{aq})\)</p>
<p>Without chemical equilibrium life as we know it would not be possible. Another example of equilibrium in our everyday lives goes on within our very bodies. Haemoglobin is a macromolecule that transports <a data-lesson="occurrence-preparation-and-compounds-of-oxygen" data-subject="chemistry" data-tutorial="metals-metalloids-nonmetals" href="https://app.ulearngo.com/chemistry/metals-metalloids-nonmetals/occurrence-preparation-and-compounds-of-oxygen">oxygen</a> around our bodies. Without it we would not survive. The haemoglobin has to be able to take up oxgen, but also to release it and this is done through changes in the chemical equilibrium of this reaction in different places in our bodies.</p>
<p>haemoglobin(aq) + \(4\text{O}_{2}(\text{g})\) \(\rightleftharpoons\) haemoglobin(\(\text{O}_{2})_{4}\)(aq)</p>
<div class="ns-school-defn2">
<h4>Fact:</h4>
<p>Haemoglobin, inside red <a data-lesson="medicine-the-buffer-system-in-blood" data-subject="chemistry" data-tutorial="acid-base-equilibria" href="https://app.ulearngo.com/chemistry/acid-base-equilibria/medicine-the-buffer-system-in-blood">blood</a> cells in the lungs, bonds with oxygen. This <em>oxyhaemoglobin</em> moves with the red blood cells through the blood stream to cells throughout the body.</p>
<img alt="" src="https://data.ulearngo.com/assets/3e40a39a-a8bb-4bef-8093-b68c24406d31"/></div>
<h3>Optional Video: Demonstration of Simulated Chemical Equilibrium</h3>
<p>This video is a good demonstration of how a reaction reaches equilibrium with time.</p>
<div class="note visit"><iframe allowfullscreen="allowfullscreen" frameborder="0" height="360" src="https://www.youtube.com/embed/C5jDmG4nVV8?rel=0&amp;modestbranding=1&amp;cc_lang_pref=en&amp;cc_load_policy=1" width="640"></iframe></div>
</section>
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What is Chemical Equilibrium?

Chemistry generally explores the substances of which matter is composed, the investigation of their properties and reactions, and the use of such reactions to form new substances. 

Chemistry

Discover the principles of Chemical Equilibrium including reversible reactions, dynamic equilibrium, and the Equilibrium Constant, learn how to calculate and interpret RICE tables, and explore the effects of concentration, temperature, pressure, and catalysts on equilibrium reactions.


What is Chemical Equilibrium?

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