CH: Stoichiometry


Stoichiometry is a fundamental concept in chemistry that deals with calculating the quantities of reactants and products involved in a chemical reaction.

To perform stoichiometric calculations, you typically start with a balanced chemical equation, which shows the identities of the reactants and products, as well as the relative number of moles or molecules of each. The coefficients in the balanced equation represent the stoichiometric ratios between the substances involved.

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Stoichiometry allows you to answer various types of questions, such as:

  1. Determining the amount of product formed from a given amount of reactant or finding the amount of reactant required to produce a certain amount of product. By using the stoichiometric ratios in the balanced equation, you can calculate the number of moles or grams of product that will be produced, or you can determine the quantity of reactant needed to obtain a desired amount of product. Watch this video for a great tutorial.
  2. Predicting the limiting reactant: The limiting reactant is the substance that is completely consumed in a reaction, limiting the amount of product that can be formed. Stoichiometry helps identify which reactant is in limited supply by comparing the amounts of each reactant and their stoichiometric ratios.
  3. Estimating percent yield: The percent yield is a measure of the efficiency of a chemical reaction and represents the actual yield (the amount of product obtained experimentally) compared to the theoretical yield (the maximum amount of product calculated using stoichiometry).

The formula to calculate % Yield is as follows:

% 𝒀𝒊𝒆𝒍𝒅 = (𝑨𝒄𝒕𝒖𝒂𝒍 𝒀𝒊𝒆𝒍𝒅 / 𝑻𝒉𝒆𝒐𝒓𝒆𝒕𝒊𝒄𝒂𝒍 𝒀𝒊𝒆𝒍𝒅) 𝒙 𝟏𝟎𝟎%

(Percent yield equals actual yield, divided by theoretical yield, and then multiplied by 100%)

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