Mass of salicylic acid used: 2.0 g Volume of acetic anhydride used: 5:0 g Mass o
ID: 992631 • Letter: M
Question
Mass of salicylic acid used: 2.0 g Volume of acetic anhydride used: 5:0 g Mass of aspirin obtained: 1.47 g Mass of acetic anhydride used: 5.4 g density=1.08 g/mL Melting point of aspirin: 140C How would I find the theoretical yield of aspirin and the percentage yield of aspirin(by mass)? Mass of salicylic acid used: 2.0 g Volume of acetic anhydride used: 5:0 g Mass of aspirin obtained: 1.47 g Mass of acetic anhydride used: 5.4 g density=1.08 g/mL Melting point of aspirin: 140C How would I find the theoretical yield of aspirin and the percentage yield of aspirin(by mass)? Volume of acetic anhydride used: 5:0 g Mass of aspirin obtained: 1.47 g Mass of acetic anhydride used: 5.4 g density=1.08 g/mL Melting point of aspirin: 140C How would I find the theoretical yield of aspirin and the percentage yield of aspirin(by mass)?Explanation / Answer
acetic anhydride+ salicylic acid ------->acetylsalicylic acid + acetic acid
C4H6O3 + C7H6O3 ------> C9H8O4 + C2H4O2
Molar mass of acetic anhydride is 102 g/mol
Molar mass of salicylic acid is 138 g/mol
Molar mass of acetylsalicylic acid is 180 g/mol
According to the balanced reaction,
102 g of acetic anhydride reacts with 138 g of salicylic acid
M g of acetic anhydride reacts with 2.0 g of salicylic acid
M = ( 2.0x102) / 138
= 1.48 g
So 5.0-1.48 = 3.52 g of acetic anhydride left unreacted so it is the excess reactant.
Since all the mass of salicylic acid completly reacted it is the limiting reacted.
From the balanced reaction,
138 g of salicylic acid produces 180 g of aspirin
2.0 g of salicylic acid produces Ng of aspirin
N = ( 2.0x180) / 138
= 2.61 g of asprin ----> this is the theoretical yield
Given actual yield is 1.47 g
So percentage of aspirin = ( acutal yield / theoretical yield) x100
= ( 1.47 / 2.61) x100
= 56.35%