Can 1 mole of H2 react partially with one mole of O2? - Chemistry Stack Exchange most recent 30 from chemistry.stackexchange.com 2019-08-19T01:53:02Z https://chemistry.stackexchange.com/feeds/question/6225 http://www.creativecommons.org/licenses/by-sa/3.0/rdf https://chemistry.stackexchange.com/q/6225 10 Can 1 mole of H2 react partially with one mole of O2? stupidSheep https://chemistry.stackexchange.com/users/2310 2013-09-15T19:27:27Z 2017-04-04T04:30:48Z <p>I am currently studying stoichiometry (high school level) and we came across the following equation in school:</p> <p>\$\ce{2H2 + 1O2 -&gt; 2H2O}\$</p> <p>which is clear to me. We learned in school that reactions in chemistry only happen if there are enough atoms/molecules to react (so every molecule/atom can react), therefore the following reaction won't do anything:</p> <p>\$\ce{1H2 + 1O2 -&gt; nothing happens}\$</p> <p>So now my first question: Why does the following not happen:</p> <p>\$\ce{1H2 + 1O2 -&gt; 1H2O + 1O}\$</p> <p>And, as a follow up question, why does the following not work?</p> <p>\$\ce{H2 + O2 -&gt; H2O + 1/2O2 (Left) }\$</p> <p>What do I do wrong? (maybe I simply misunderstood our teacher)</p> <p>Are there any explanations for this? I'm especially interested in the answer of my example with \$1\$ mole of \$\ce{H2}\$ and \$1\$ mole of \$\ce{O2}\$. According to our teacher nothing will happen at all. I would assume that at least all \$\ce{H2}\$ molecules react with half of the oxygen molecules to \$\ce{H2O}\$ - leaving half a mole of \$\ce{O2}\$ left over. (otherwise this would mean that all molecules "know" each other so they are "aware" that not all molecules/atoms can react) </p> <p>Can somebody help me? Or point out what I am doing wrong?</p> https://chemistry.stackexchange.com/questions/6225/can-1-mole-of-h2-react-partially-with-one-mole-of-o2/6226#6226 20 Answer by ashu for Can 1 mole of H2 react partially with one mole of O2? ashu https://chemistry.stackexchange.com/users/1878 2013-09-15T20:34:22Z 2015-12-17T09:38:58Z <p>As you have said, you are studying stoichiometry at <strong>High School Level</strong>. From this I can guess, that you have probably not studied the <strong><a href="http://en.wikipedia.org/wiki/Limiting_reagent" rel="nofollow">concept of Limiting Reagent</a></strong> yet.</p> <h2><strong>What is Limiting Reagent?</strong></h2> <blockquote> <p>In a chemical reaction, the limiting reagent, also known as the "limiting reactant", is the substance which is totally consumed when the chemical reaction is complete. The amount of product formed is limited by this reagent since the reaction cannot proceed further without it. The other reagents may be present in excess of the quantities required to react with the limiting reagent.</p> </blockquote> <p>As per your question, \$\ce{H2}\$ is limiting reagent. Hence it will get totally consumed when reaction happens and 1/2 Moles of \$\ce{O2}\$ will be left.</p> <blockquote> <p>1 mole of H2 and 1 mole of O2 won't make 1 mole of H2O and 1/2 mole O2.</p> </blockquote> <p>1 mole of \$\ce{H2}\$ and 1 mole of \$\ce{O2}\$ <strong>will make</strong> 1 mole of \$\ce{H2O}\$ and 1/2 mole \$\ce{O2}\$ will be left.</p> <p>\$\ce{H2 + O2 -&gt; H2O + 1/2O2 (Left) }\$</p> <p>And here is an advice for you. If your teacher is saying that this will not happen at all, tell him to be sure that reactant in reaction are single <strong>molecules</strong>, not 1 <strong>mole</strong>.</p> <p>Read <a href="http://en.wikipedia.org/wiki/Limiting_reagent" rel="nofollow">this</a> to be more clear on concept of limiting reagent.</p>