Second, we calculated the theoretical yield.First, we went to the lab, ran the reaction, and found our actual yield.In fact, you could find yourself with a percent yield greater than 100%, which should be impossible, and often indicates that either your calculations are incorrect or your product is heavily contaminated.Īlright, before you try an example on your own, let’s review the steps we took to calculate the percent yield for our banana oil reaction. So if anything, we may be overestimating our actual yield.
Basically, without further testing, we don’t know the purity of our product we’re just assuming that it’s 100% banana oil. But what if there was some leftover acetic acid in our product (after all, we added it in excess)? Or maybe some water since that was a product too. The reasons will vary from reaction to reaction, so some critical analysis will be necessary.Īlso, note that we did make an assumption about the mass of our product. Maybe we didn’t allow the reaction enough time or provide enough energy or maybe the chemical equilibrium lies close to the reactants. Or maybe there’s a competing side reaction that produces a different product.
Maybe you lost a lot of product during extraction or purifying steps. Whenever you find yourself with a low percent yield, it’s always good to reflect on why that happened. Ideally, we want the percent yield of a reaction to be higher to avoid wasting resources and energy. Remember, percent yield equals the actual yield divided by the theoretical yield times 100%, which gives us 77%. The simple definition of percent yield is the actual yield divided by the theoretical yield times 100 (to convert to a percentage). As this is a concept best learned through practice, we’ll start with a quick definition but then jump right into some examples. Hi, and welcome to this video on calculating the percent yield of a chemical reaction! It’s an important concept, particularly in the laboratory, and is often used as a method for measuring the success of a reaction.
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