Asprin, C9H8O4, is prepared by reacting salicylic acid, C7H6O3, with acetic anhydride, C4H6O3.

The other product is acetic acid C2H4O2,

C9h8o4 + C4H6O3 -> C9H8O4 + C2H4O2

when 2.00 g of salicylic acid is heated with 4.00 g of acetic anhydride.

If the actual yield of aspirin is 2.1 g, what is the percentage yield?

This is a limiting regent(LR) problem. Your equation is wrong; i.e., you started with aspirin to form aspirin. You meant to start with salicylic acid (SA). I will shorten these formulas to

C7H6O3 + C4H6O3 -> C9H8O4 + C2H4O2
SA + AH(acetic anhydride) => ASA(aspirin) = HAc(acetic acid)

mols SA = grams/molar mass = ?
mols AH = grams/molar mass = ?

Find the LR this way.
Convert mols SA to mols ASA. That's done by using the coefficients in the balanced equation; i.e., mols SA x (1 mol ASA/1 mol SA) = ? mols ASA.
Do the same and convert mols AH to mols ASA.
The SMALLER number always wins in LR problems and the LR is the reagent producing the smaller mols product.
Now convert mols ASA (the product you want) to grams. g = mols x molar mass = ?. This is the theoretical yield (TY). The actual yield (AY) in the problem is given as 2.1 g.
% yield = (AY/TY)*100 = ?
Post your work if you get stuck.

кДчЯ

To calculate the percentage yield, we need to compare the actual yield of the product to the theoretical yield.

First, let's find the theoretical yield of aspirin. We can use the given mass of salicylic acid to calculate the moles of salicylic acid, and then use the balanced equation to determine the moles of aspirin formed.

1. Calculate the moles of salicylic acid (C7H6O3):
Molar mass of salicylic acid (C7H6O3) = (12.01*7) + (1.01*6) + (16.00*3) = 138.12 g/mol

Moles of salicylic acid = mass (g) / molar mass (g/mol) = 2.00 g / 138.12 g/mol = 0.0145 mol

2. Use the balanced equation to determine the moles of aspirin (C9H8O4) formed:
From the equation: 1 mol salicylic acid produces 1 mol aspirin
Therefore, moles of aspirin = moles of salicylic acid = 0.0145 mol

3. Calculate the mass of aspirin using the molar mass of aspirin:
Molar mass of aspirin (C9H8O4) = (12.01*9) + (1.01*8) + (16.00*4) = 180.16 g/mol

Theoretical yield of aspirin = moles of aspirin * molar mass of aspirin = 0.0145 mol * 180.16 g/mol = 2.61 g

Now we can calculate the percentage yield:

Percentage yield = (Actual yield / Theoretical yield) * 100%
= (2.10 g / 2.61 g) * 100%
≈ 80.46%

Therefore, the percentage yield of aspirin is approximately 80.46%.