Monday in class we continued with the method that we had already learned, and applied it to solving for what are called the limiting reagent and the excess reagent. The limiting reagent whichever conversion ends up as the smaller number, and this number is the maximum amount of product that can be made. The limiting reagent is called this because the reaction will occur until this reactant runs out, and the other reactant in the reaction will be leftover in excess. The excess reagent is the larger number in these conversions, but its amount is not this number. To find the amount of excess reagent, you must take the amount of the limiting reagent and use the conversions to put it in the correct labeling for the excess. For example, if the limiting reagent was 10.5g NH3, then you would take the 10.5gNH3 and convert it to grams of Ca(OH)2, the excess reagent. Once this is converted, you will take that number and subtract it from the original amount, and finally you will know how much is left.
These images show how some of the reactants form the products, but the red leftovers are the excess reagents we solve for.
This link helped me the most, even though it has silly illustrations:
https://www.khanacademy.org/science/chemistry/chemical-reactions-stoichiome/limiting-reagent-stoichiometry/a/limiting-reagents-and-percent-yield
Here are some other links that helped me with this lesson:
Website:
https://www.chem.tamu.edu/class/majors/tutorialnotefiles/limiting.htm
Video:
https://www.youtube.com/watch?v=qLUJdF_l8LA
Holly, thank you for this great post! Your explanation of what a limiting reagent is made it really easy to understand. Also, the pictures are way more helpful than any that I was able to find on my own, so thank you for those. Lastly, all of the links you included were really informational and I'm sure they will help me when studying for this test :)
ReplyDeleteHolly, I found your post very helpful and detailed. Your explanation distinguishing the difference between limiting and excess reagent was very clear. Also, the example you added at the end of it showed that you fully understood the concept. Lastly, the pictures you posted gave me a visual at what happens in all reactions. It can be hard to imagine what is really going on, and the pictures helped me comprehend how the molecules and atoms move in a reaction.
ReplyDeleteThis was a great post Holly. The example helped and the pictures were a good visual. Also the link and the video helped a lot.
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