How would you calculate the percent yield for a reaction that began with 10 moles of acetone and 16 moles of benzaldehyde which yielded 6 moles of dibenzalacetone as the product? The molecular weights are as follows (acetone = 58.08 g/mole), (benzaldehyde = 106.2 g/mole), (dibenzalacetone = 234.3 g/mole. Thanks.
1. Write the balanced equation.
2. Calculate theoretical yield; i.e., how much product (in mols) SHOULD you get, using stoichiometry.
3. Then
%yield = [6 mols/theoretical mols]x100 =??
To calculate the percent yield of a reaction, you'll need to follow these steps:
1. Write the balanced equation: To do this, you'll need to know the reactants and products involved in the reaction. In this case, you have acetone (C3H6O) and benzaldehyde (C7H6O), which react to form dibenzalacetone (C17H14O). The balanced equation would be:
2 C3H6O + 3 C7H6O → C17H14O + H2O
2. Calculate the theoretical yield: The theoretical yield is the maximum amount of product that can be obtained from the given reactants. You can determine the theoretical yield by using stoichiometry and the balanced equation. Start by calculating the molar ratios between the reactants and the product. From the balanced equation, you can see that 2 moles of acetone react with 3 moles of benzaldehyde to produce 1 mole of dibenzalacetone.
Since you have 10 moles of acetone and 16 moles of benzaldehyde, you need to determine which reactant will be the limiting reactant. The limiting reactant is the one that is completely consumed and determines the maximum amount of product that can be formed. To find the limiting reactant, compare the ratios of moles of reactants to moles required according to the balanced equation.
For acetone: 10 moles * (3 moles/2 moles) = 15 moles of benzaldehyde required
For benzaldehyde: 16 moles * (2 moles/3 moles) = 10.67 moles of acetone required
Since you have less than the required amount of benzaldehyde, it is the limiting reactant. Therefore, the moles of benzaldehyde (10 moles) will determine the maximum moles of dibenzalacetone that can be formed.
Next, convert the moles of dibenzalacetone to grams using the molar mass:
The molar mass of dibenzalacetone is given as 234.3 g/mol.
The theoretical yield in grams = moles of dibenzalacetone * molar mass of dibenzalacetone
Theoretical yield = 10 moles * 234.3 g/mol = 2343 g
3. Calculate the percent yield: The percent yield is the actual yield (in this case, the given yield of 6 moles) divided by the theoretical yield, multiplied by 100.
% yield = (actual yield / theoretical yield) * 100
% yield = (6 moles / 10 moles) * 100 = 60%
Therefore, the percent yield for this reaction is 60%.