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# How to Calculate Theoretical Yields

❶You can determine this by the coefficients in front of your desired reactant and product in your balanced equation.   Calculate the theoretical mole yield by using the chemical equation. The multiply the ratio between the limiting reagent and the product by the number of moles of the limiting reagent used in the experiment. Multiply the number of moles of the product by the molecular weight of the product to determine the theoretical yield. For example, if you created 0. Mark Kennan is a writer based in the Kansas City area, specializing in personal finance and business topics.

Here's a Calculator to Help You X. Things Needed Calculator Chemical equation Molecular weights of compounds used. The answer is the theoretical yield of the desired product in moles. You started with 0. The theoretical yield of carbon dioxide is 0. Convert the result to grams. Multiply your answer in moles by the molar mass of that compound to find the theoretical yield in grams. This is a more convenient unit to use in most experiments. The theoretical yield of the experiment is The theoretical yield you calculated assumes that everything went perfectly.

In an actual experiment, this never happens: This is why chemists use 3 different concepts to refer to yield: The theoretical yield is the maximum amount of product the experiment could make. The actual yield is the actual amount you created, measured directly on a scale. Write down the actual yield of the experiment. If you performed the experiment yourself, gather the purified product from your reaction and weigh it on a balance to calculate its mass.

If you are working on a homework problem or someone else's notes, the actual yield should be listed. Divide the actual yield by the theoretical yield. Make sure you use the same units for both values typically grams. Your answer will be a unit-less ratio. The actual yield was 29 grams, while the theoretical yield was Multiply by to convert to a percentage. The answer is the percent yield.

If in the reaction is below 32 of C2H6 and produces 44 grams of CO2, what is the percent yield? This is your theoretical yield based on the 32g of C2H6 you started with and the molar ratio between C2H6 and CO2 in your balanced equation. Not Helpful 0 Helpful 1.

You can determine this by the coefficients in front of your desired reactant and product in your balanced equation. Not Helpful 1 Helpful 1. How do I calculate the percentage yield when I'm only given the volume of the reactants? Not Helpful 6 Helpful Well water is composed of 3 atoms, 2 hydrogen and 1 oxygen. Not Helpful 7 Helpful What do I do with mols in different atoms when calculating the percentage yield?

Actual yield divided by theoretical yield. Not Helpful 10 Helpful How do I calculate the limiting reactant when calculating the percent yield? Find the number of moles of the reactants and compare them. The reactant with the least number of moles will be your limiting reactant. Actual yield is the mass that will be given to you after the experiment or in the exam question. However, the actual yield will nearly always be given.

Not Helpful 7 Helpful 1. Where can I find more examples that will help me solve specific problems that I need to calculate?

In other words, this reaction can produce 6 molecules of carbon dioxide from one molecule of glucose. Multiply the ratio by the limiting reactant's quantity in moles. The answer is the theoretical yield, in moles, of the desired product.

In this example, the 25g of glucose equate to 0. The ratio of carbon dioxide to glucose is 6: You expect to create six times as many moles of carbon dioxide as you have of glucose to begin with. The theoretical yield of carbon dioxide is 0. Convert the result to grams. This is the reverse of your earlier step of calculating the number of moles or reactant. When you know the number of moles that you expect, you will multiply by the molar mass of the product to find the theoretical yield in grams.

The theoretical yield of the experiment is Repeat the calculation for the other product if desired. In many experiments, you may only be concerned with the yield of one product.

If you wish to find the theoretical yield of both products, just repeat the process. According to the balanced equation, you expect 6 molecules of water to come from 6 molecules of glucose. This is a ratio of 1: Therefore, beginning with 0. Multiply the number of moles of water by the molar mass of water. Multiplying by the product, this results in 0. The theoretical yield of water for this experiment is 2. Doesn't one molecule of glucose produce six molecules of water, not one?

Not Helpful 0 Helpful 2. Your final step with the image you provided does not match. Is the theoretical mass of water 15 grams or 2. Answer this question Flag as Include your email address to get a message when this question is answered.

Already answered Not a question Bad question Other. Quick Summary To calculate theoretical yield, start by finding the limiting reactant in the equation, which is the reactant that gets used up first when the chemical reaction takes place. Did this summary help you? Chemistry Calculations In other languages: Thanks to all authors for creating a page that has been read , times. ## Main Topics

Use molar mass of reactant to convert grams of reactant to moles of reactant. Use the mole ratio between reactant and product to convert moles reactant to moles product. Use the molar mass of the product to convert moles product to grams of product.

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Knowing the theoretical yield helps determine a reaction's efficiency. This is important to know at any level, from beginning chemistry students to industrial chemists seeking to .