if 1.5g of salicylic acid is heated with an excess of acetic anhydride, what is the theoretical yield of acetylsalicylic acid?
Here is a solved example of a stoichiometry problem which will give you the theoretical yield. Post your work if you get stuck.
http://www.jiskha.com/science/chemistry/stoichiometry.html
To determine the theoretical yield of acetylsalicylic acid, we need to calculate the molar mass of both salicylic acid and acetylsalicylic acid. Here is the step-by-step explanation:
Step 1: Calculate the number of moles of salicylic acid.
To find the number of moles, use the given mass and the molar mass of salicylic acid.
The molar mass of salicylic acid is:
C7H6O3 = (12.01 g/mol x 7) + (1.01 g/mol x 6) + (16.00 g/mol x 3) = 138.12 g/mol
Moles of salicylic acid = (1.5 g) / (138.12 g/mol)
Moles of salicylic acid = 0.01086 mol
Step 2: Determine the stoichiometry between salicylic acid and acetylsalicylic acid.
From the balanced chemical equation for the reaction of salicylic acid with acetic anhydride:
C7H6O3 + (C4H6O3)n → C9H8O4 + CH3COOH
The stoichiometry is 1:1, meaning that one mole of salicylic acid reacts with one mole of acetic anhydride to produce one mole of acetylsalicylic acid.
Step 3: Calculate the theoretical yield of acetylsalicylic acid.
Since there is an excess of acetic anhydride (meaning it will not limit the reaction), the number of moles of acetylsalicylic acid formed will be equal to the number of moles of salicylic acid used.
So, the theoretical yield of acetylsalicylic acid = 0.01086 mol
To convert the theoretical yield from moles to grams, multiply the number of moles by the molar mass of acetylsalicylic acid.
The molar mass of acetylsalicylic acid is:
C9H8O4 = (12.01 g/mol x 9) + (1.01 g/mol x 8) + (16.00 g/mol x 4) = 180.16 g/mol
Theoretical yield of acetylsalicylic acid = (0.01086 mol) × (180.16 g/mol)
Theoretical yield of acetylsalicylic acid = 1.955 g
Therefore, the theoretical yield of acetylsalicylic acid is approximately 1.955 grams.