Article: The right side of a chemical equation shows the products created by the reaction. The coefficients of each product, if the reaction is balanced, tells you the amount to expect, in molecular ratios. Each product has a theoretical yield, meaning the amount of product you would expect to get if the reaction is perfectly efficient. Continuing the example above, you are analyzing the reaction 6O2+C6H12O6{\displaystyle 6O_{2}+C_{6}H_{12}O_{6}} 6CO2+6H2O{\displaystyle 6CO_{2}+6H_{2}O}. The two products shown on the right are carbon dioxide and water. You can begin with either product to calculate theoretical yield. In some cases, you may be concerned only with one product or the other. If so, that is the one you would start with. You must always compare moles of reactant to moles of product. If you try to compare the mass of each, you will not reach the correct results. In the example above, glucose is the limiting reactant. The molar mass calculations found that the initial 25g of glucose are equal to 0.139 moles of glucose. Return to the balanced equation. Divide the number of molecules of your desired product by the number of molecules of your limiting reactant. The balanced equation for this example is 6O2+C6H12O6{\displaystyle 6O_{2}+C_{6}H_{12}O_{6}} 6CO2+6H2O{\displaystyle 6CO_{2}+6H_{2}O}. This equation tells you that you expect 6 molecules of the desired product, carbon dioxide (CO2{\displaystyle CO_{2}}), compared to 1 molecule of glucose (C6H12O6{\displaystyle C_{6}H_{12}O_{6}}). The ratio of carbon dioxide to glucose is 6/1 = 6. In other words, this reaction can produce 6 molecules of carbon dioxide from one molecule of glucose. The answer is the theoretical yield, in moles, of the desired product. In this example, the 25g of glucose equate to 0.139 moles of glucose. The ratio of carbon dioxide to glucose is 6:1. 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 (0.139 moles glucose) x (6 moles carbon dioxide / mole glucose) = 0.834 moles carbon dioxide. 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. In this example, the molar mass of CO2 is about 44 g/mol. (Carbon's molar mass is ~12 g/mol and oxygen's is ~16 g/mol, so the total is 12 + 16 + 16 = 44.) Multiply 0.834 moles CO2 x 44 g/mol CO2 = ~36.7 grams. The theoretical yield of the experiment is 36.7 grams of CO2. 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. In this example, the second product is water, H2O{\displaystyle H_{2}O}. According to the balanced equation, you expect 6 molecules of water to come from 1 molecule of glucose. This is a ratio of 6:1. Therefore, beginning with 0.139 moles of glucose should result in 0.834 moles of water. Multiply the number of moles of water by the molar mass of water. The molar mass is 2 + 16 = 18 g/mol. Multiplying by the product, this results in 0.834 moles H2O x 18 g/mol H2O = ~15 grams. The theoretical yield of water for this experiment is 15 grams.
Question: What is a summary of what this article is about?
Review the reaction to find the desired product. Write down the number of moles of your limiting reactant. Compare the ratio of molecules in product and reactant. Multiply the ratio by the limiting reactant's quantity in moles. Convert the result to grams. Repeat the calculation for the other product if desired.

Depending on the type of biological control that you use, you may need to get a permit from your local department of wildlife or agriculture. Some species that can control lake weeds are considered invasive in particular areas, and you may not be allowed to introduce them. Always learn what your local laws are before introducing a new animal or fish into your lake. Mute swans can be released onto small lakes. As they feed on both submerged plants and algae, they may be ideal to control vegetation. Keep in mind that swans require extra care, husbandry, and protection from predators. Also known as the white amur, grass carp feed on the submersed plants in your lake. They are usually introduced into a lake to control vegetation. Keep in mind that grass carp will eat almost any submerged vegetation, not just invasive species or weeds. Grass carp will not help much with duckweed or watermeal. It is recommended that you stock 15 to 30 fish per acre of lake. Get carp that are at least ten or twelve inches long. Grass carp can be invasive. Check your local laws to make sure that you are allowed to use them as a biological control before you release them into your lake. If you want to target a specific weed, you may look into using insects as form of biological control. You will need to find insects that are host-specific; this means you pick a species of insects that will only eat the specific weed that you want to remove. You can research your particular weed to see if there is an insect species that may help. You might also reach out to your local department of wildlife or agriculture, Noxious Weed Control Board, or an ecologist. Do not release non-native insects until you have verified that they will only eat the plant in question and that they will have no other impact on your local ecosystem.
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Check your local laws. Introduce swans to the lake. Release grass carp into the lake. Research which insects may be helpful.