Aspirin (C9H8O4) is synthesized by reacting salicylic acid (C7H6O3) with acetic anhydride (C4H6O3). The balanced equation is given below.
C7H6O3 + C4H6O3 C9H8O4 + HC2H3O2
(a) What mass of acetic anhydride is needed to completely consume 4.40 102 g salicylic acid? What is the maximum mass of aspirin (the theoretical yield) that could be produced in this reaction?
Here is a problem I have posted that gives the basic steps for stoichiometric problems. It isn't the same problem but most of them are worked the same way. Here is the link.
http://www.jiskha.com/science/chemistry/stoichiometry.html
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To find the mass of acetic anhydride needed to completely consume 4.40 x 10^2 g of salicylic acid, we need to use stoichiometry and the balanced equation.
The balanced equation gives us the molar ratio between salicylic acid and acetic anhydride as 1:1. This means that for every mole of salicylic acid consumed, 1 mole of acetic anhydride is needed.
To find the number of moles of salicylic acid, we divide its mass by its molar mass. The molar mass of salicylic acid (C7H6O3) is 138.12 g/mol.
Number of moles of salicylic acid = mass of salicylic acid / molar mass
= 4.40 x 10^2 g / 138.12 g/mol
Next, using the stoichiometry from the balanced equation, we can find the number of moles of acetic anhydride needed.
Number of moles of acetic anhydride = Number of moles of salicylic acid
Now, we need to find the mass of acetic anhydride using its molar mass, which is 102.09 g/mol.
Mass of acetic anhydride = Number of moles of acetic anhydride × molar mass
= Number of moles of salicylic acid × molar mass of acetic anhydride
Now, let's calculate the mass of acetic anhydride needed to completely consume 4.40 x 10^2 g of salicylic acid.
Mass of acetic anhydride = (4.40 x 10^2 g / 138.12 g/mol) × 102.09 g/mol
To find the maximum mass of aspirin that could be produced (the theoretical yield), we need to consider the stoichiometry of the balanced equation. The molar ratio between salicylic acid and aspirin is also 1:1.
Using the same approach as before, we can find the number of moles of salicylic acid:
Number of moles of salicylic acid = 4.40 x 10^2 g salicylic acid / 138.12 g/mol
Since the molar ratio of salicylic acid to aspirin is 1:1, the number of moles of salicylic acid equals the number of moles of aspirin.
Now, we can calculate the maximum mass of aspirin that could be produced.
Maximum mass of aspirin (theoretical yield) = Number of moles of aspirin × molar mass of aspirin
= Number of moles of salicylic acid × molar mass of aspirin
The molar mass of aspirin (C9H8O4) is 180.16 g/mol.
Maximum mass of aspirin = (4.40 x 10^2 g salicylic acid / 138.12 g/mol) × 180.16 g/mol
By performing these calculations, you can determine the mass of acetic anhydride needed to consume salicylic acid and the maximum mass of aspirin that could be produced in this reaction.