Limiting and Excess Reactants

In 1973, oil exports coming from the Middle East decreased. The end result was a gas shortage in the United States. Did this stop many cars from driving on the roads? No. Cars continued to drive and gas stations experienced long lines. Many gas stations had days when they were completely out of gas. Some stations even had signs to limit drivers, like the one seen in the image on this page. The gas supply was the limiting reagent in the equation.

In a chemical reaction, the amount of the reactants determines how much of the product is formed. It is necessary for some reactions to take place with unequal amounts of reactants. This means one reactant will run out before the other. The lesser reactant becomes a limiting reactant. As soon as it runs out, the reaction will end. Many other processes have a type of limiting reactant.

Can you think of any process that has a limiting reactant? What is the impact of a shortage of that reactant? Post your responses to these questions in the discussions area. Then, return to the topic several times over the next few days to read your coursemates’ posts. Reply to at least two of them, being sure to offer new insights, ask questions, and encourage further conversation.