A 0.300 g sample of an aspirin tablet is used to prepare 100.0 mL of a stock solution by dissolving the tablet in 1 M NaOH then diluting with distilled water to the 100 mL mark of a volumetric flask. A 0.30 mL sample of the stock solution is then transferred to a volumetric flask and diluted with 0.02 M iron(III) chloride to the 10.00 mL mark. The tetraaquasalicylatoiron(III) complex concentration in this 10.00 mL sample is determined to be 4.3x10-4M. What is the percentage of acetylsalicylic acid in the original aspirin tablet? Do not include the % sign in your answer. For example, for a value of 100% enter 100.
To find the percentage of acetylsalicylic acid in the original aspirin tablet, we need to calculate the concentration of acetylsalicylic acid in the stock solution and then use this value to find the amount of acetylsalicylic acid in the tablet.
Step 1: Calculate the concentration of the tetraaquasalicylatoiron(III) complex in the 10.00 mL sample.
Given:
- Volume of the stock solution transferred = 0.30 mL
- Volume of the final sample = 10.00 mL
- Concentration of the tetraaquasalicylatoiron(III) complex = 4.3x10^-4 M
To calculate the concentration of the tetraaquasalicylatoiron(III) complex in the 10.00 mL sample, we can use the formula:
C1V1 = C2V2
Where:
C1 = initial concentration (4.3x10^-4 M)
V1 = initial volume (0.30 mL)
C2 = final concentration (unknown)
V2 = final volume (10.00 mL)
Rearranging the formula, we have:
C2 = (C1 * V1) / V2
C2 = (4.3x10^-4 M * 0.30 mL) / 10.00 mL
C2 = 1.29x10^-5 M
Therefore, the concentration of the tetraaquasalicylatoiron(III) complex in the 10.00 mL sample is 1.29x10^-5 M.
Step 2: Calculate the concentration of acetylsalicylic acid in the stock solution.
The tetraaquasalicylatoiron(III) complex is formed by the reaction between acetylsalicylic acid in the stock solution and iron(III) chloride in the diluting solution. The ratio between the complex and the acetylsalicylic acid can be determined using stoichiometry.
Let's assume the balanced equation for the reaction is:
FeCl3 + C9H8O4 → [Fe(C9H7O4) (H2O)4] + 3HCl
According to the equation, the molar ratio between the complex and acetylsalicylic acid is 1:1.
Since the concentration of the complex is 1.29x10^-5 M, the concentration of acetylsalicylic acid in the stock solution is also 1.29x10^-5 M.
Step 3: Calculate the amount (in moles) of acetylsalicylic acid in the stock solution.
Given:
- Volume of the stock solution = 100.0 mL = 0.100 L
- Concentration of acetylsalicylic acid in the stock solution = 1.29x10^-5 M
The amount (in moles) of acetylsalicylic acid in the stock solution can be calculated using the formula:
moles = concentration * volume
moles = 1.29x10^-5 M * 0.100 L
moles = 1.29x10^-6 mol
Step 4: Calculate the mass of the acetylsalicylic acid in the stock solution.
Given:
- Mass of the aspirin tablet = 0.300 g
The molar mass of acetylsalicylic acid (C9H8O4) is 180.16 g/mol.
The mass of the acetylsalicylic acid in the stock solution can be calculated using the formula:
mass = moles * molar mass
mass = 1.29x10^-6 mol * 180.16 g/mol
mass = 0.0002328728 g
Step 5: Calculate the percentage of acetylsalicylic acid in the original aspirin tablet.
The percentage of acetylsalicylic acid in the original aspirin tablet can be calculated using the formula:
percentage = (mass of acetylsalicylic acid / mass of the aspirin tablet) * 100
percentage = (0.0002328728 g / 0.300 g) * 100
percentage ≈ 0.0776%
Therefore, the percentage of acetylsalicylic acid in the original aspirin tablet is approximately 0.0776%.
To calculate the percentage of acetylsalicylic acid in the original aspirin tablet, we need to determine the concentration of acetylsalicylic acid in the stock solution and then use that information to find the percentage.
Let's start by finding the concentration of the tetraaquasalicylatoiron(III) complex in the 10.00 mL sample.
Given:
Volume of the 10.00 mL sample = 0.30 mL
Concentration of the tetraaquasalicylatoiron(III) complex = 4.3x10^(-4) M
Since we diluted the 0.30 mL sample to 10.00 mL, we can calculate the concentration of the tetraaquasalicylatoiron(III) complex in the 10.00 mL sample using the dilution equation:
C1V1 = C2V2
Where:
C1 = initial concentration
V1 = initial volume
C2 = final concentration
V2 = final volume
Let's plug in the values:
(4.3x10^(-4)) * (0.30) = C2 * (10.00)
C2 = (4.3x10^(-4) * 0.30) / 10.00
C2 = 1.29x10^(-4) M
Now that we know the concentration of the tetraaquasalicylatoiron(III) complex, which is formed by the reaction of acetylsalicylic acid with iron(III) chloride, we can calculate the molar ratio between acetylsalicylic acid and the complex.
The reaction equation is:
2C9H8O4 + FeCl3 -> [Fe(C9H7O4)2(H2O)2] + 3HCl
From the balanced equation, we can see that 2 moles of acetylsalicylic acid react with 1 mole of the tetraaquasalicylatoiron(III) complex.
Therefore, the concentration of acetylsalicylic acid in the stock solution is:
1.29x10^(-4) M * 1/2 = 6.45x10^(-5) M
Now, we can calculate the number of moles of acetylsalicylic acid present in the stock solution.
Number of moles = concentration * volume
Number of moles = 6.45x10^(-5) M * 0.300 mL (converted to L)
Next, we need to convert the mass of the aspirin tablet sample to moles.
Given:
Mass of the aspirin tablet sample = 0.300 g
Molar mass of acetylsalicylic acid (C9H8O4) = 180.16 g/mol
Number of moles of acetylsalicylic acid in the stock solution = (6.45x10^(-5) mol/L) * (0.300 mL / 1000 mL/ L) = 1.94x10^(-5) mol
Finally, we can calculate the percentage of acetylsalicylic acid in the original aspirin tablet.
Percentage = (moles of acetylsalicylic acid / moles of aspirin tablet) * 100
Percentage = (1.94x10^(-5) mol / (0.300 g / 180.16 g/mol)) * 100
Now, we can calculate the percentage:
Percentage = (1.94x10^(-5) mol / (0.300 g / 180.16 g/mol)) * 100 = 1.94%
Therefore, the percentage of acetylsalicylic acid in the original aspirin tablet is 1.94%.