Acetylsalicylic acid (C9H8O4) is a monoprotic acid commonly known as "aspirin." A typical aspirin tablet, however, contains only a small amount of the acid. In an experiment to determine its composition, an aspirin tablet was crushed and dissolved in water. It took 12.25 mL of 0.1466 M NaOH to neutralize the solution. Calculate the number of grains of aspirin in the tablet. (One grain = 0.0648 g.)

Question

Acetylsalicylic acid (C9H8O4) is a monoprotic acid commonly known as "aspirin." A typical aspirin tablet, however, contains only a small amount of the acid. In an experiment to determine its composition, an aspirin tablet was crushed and dissolved in water. It took 12.25 mL of 0.1466 M NaOH to neutralize the solution. Calculate the number of grains of aspirin in the tablet. (One grain = 0.0648 g.)

Answer 1

mols NaOH = M x L = ?

mols aspirin = mols NaOH
grams aspirin = mols aspirin x molar mass aspirin

Then use the conversion factor to convert to grains. It should be close to 5 grains

Answer 2

To calculate the number of grains of aspirin in the tablet, we need to determine the number of moles of acetylsalicylic acid in the solution.

Step 1: Calculate the number of moles of NaOH used.
The volume of NaOH used is 12.25 mL, and its concentration is 0.1466 M (moles per liter).
Convert the volume from milliliters to liters:
12.25 mL ÷ 1000 mL/L = 0.01225 L

Calculate the number of moles of NaOH:
0.01225 L × 0.1466 mol/L = 0.001795 mol

Step 2: Determine the stoichiometry between NaOH and acetylsalicylic acid.
From the balanced chemical equation for the acid-base reaction between NaOH and acetylsalicylic acid, we know:
1 mol of NaOH reacts with 1 mol of acetylsalicylic acid.

Step 3: Calculate the number of moles of acetylsalicylic acid.
Since the stoichiometry is 1:1, the number of moles of acetylsalicylic acid is also 0.001795 mol.

Step 4: Calculate the mass of acetylsalicylic acid.
The molar mass of acetylsalicylic acid (C9H8O4) is calculated as follows:
(9 × 12.01 g/mol) + (8 × 1.008 g/mol) + (4 × 16.00 g/mol) = 180.16 g/mol

Calculate the mass of acetylsalicylic acid:
0.001795 mol × 180.16 g/mol = 0.3238 g

Step 5: Convert the mass of acetylsalicylic acid to grains.
One grain is equal to 0.0648 g.

Calculate the number of grains:
0.3238 g ÷ 0.0648 g/grain = 4.99 grains (approximately 5 grains)

Therefore, there are approximately 5 grains of aspirin in the tablet.

Answer 3

To calculate the number of grains of aspirin in the tablet, we need to determine the number of moles of aspirin and then convert it to grams and finally to grains.

Here's how we can approach the problem:

1. First, let's determine the number of moles of NaOH used in the neutralization reaction. We can use the molarity and volume of NaOH to calculate this. The equation for the reaction between NaOH and aspirin is:

2 C9H8O4 + 4 NaOH → 4 C9H7O4Na + 2 H2O

Moles of NaOH = Molarity of NaOH × Volume of NaOH (in liters)
= 0.1466 mol/L × 0.01225 L
= 0.001795 mol

2. Since the balanced equation shows that for every 2 moles of NaOH, we have 1 mole of aspirin, we can calculate the number of moles of aspirin in the tablet:

Moles of aspirin = 0.001795 mol ÷ 2
= 0.0008975 mol

3. Next, we need to convert the moles of aspirin to grams. To do this, we use the molar mass of aspirin:

Molar mass of aspirin (C9H8O4) = (9 × atomic mass of C) + (8 × atomic mass of H) + (4 × atomic mass of O)
= (9 × 12.01 g/mol) + (8 × 1.01 g/mol) + (4 × 16.00 g/mol)
= 180.16 g/mol

Mass of aspirin = Moles of aspirin × Molar mass of aspirin
= 0.0008975 mol × 180.16 g/mol
= 0.1615 g

4. Finally, we can convert the mass of aspirin to grains by dividing by the mass of one grain (0.0648 g):

Number of grains of aspirin = Mass of aspirin ÷ Mass of one grain
= 0.1615 g ÷ 0.0648 g
= 2.495 grains

Therefore, the number of grains of aspirin in the tablet is approximately 2.495 grains.