Determining Moles of Aspirin in a Tablet: A Crucial Calculation for Pharmaceutical Accuracy

Determining the number of moles of aspirin in a tablet is crucial for ensuring accurate dosage and efficacy in pharmaceutical applications. This measurement helps in precise pharmaceutical calculations, ensuring that each tablet contains the correct amount of active ingredient. Additionally, it plays a vital role in quality control, verifying the consistency and safety of the medication produced.

Molecular Formula and Molar Mass of Aspirin

The molecular formula of aspirin is C₉H₈O₄. This means each molecule of aspirin contains:

• 9 carbon © atoms
• 8 hydrogen (H) atoms
• 4 oxygen (O) atoms

To calculate the molar mass of aspirin, you sum the atomic masses of all the atoms in the formula:

1. Carbon ©: 12.01 g/mol × 9 = 108.09 g/mol
2. Hydrogen (H): 1.01 g/mol × 8 = 8.08 g/mol
3. Oxygen (O): 16.00 g/mol × 4 = 64.00 g/mol

Adding these together gives the molar mass of aspirin:

$$108.09 + 8.08 + 64.00 = 180.17 \, \text{g/mol}$$108.09+8.08+64.00=180.17g/mol

This molar mass is essential for determining the number of moles of aspirin in a tablet. If you have the mass of the aspirin in the tablet, you can use the formula:

$$\text{Number of moles} = \frac{\text{mass of aspirin (g)}}{\text{molar mass (g/mol)}}$$Number of moles=molar mass (g/mol)mass of aspirin (g)​

For example, if a tablet contains 360 mg (0.360 g) of aspirin:

$$\text{Number of moles} = \frac{0.360 \, \text{g}}{180.17 \, \text{g/mol}} \approx 0.002 \, \text{moles}$$Number of moles=180.17g/mol0.360g​≈0.002moles

Calculating Moles from Mass

Here’s a step-by-step example of calculating the number of moles of aspirin in a tablet using the formula:

Formula:
[ \text{moles} = \frac{\text{mass (g)}}{\text{molar mass (g/mol)}} ]

Example Calculation:

1. Determine the mass of aspirin in the tablet:

   • Let’s say the tablet contains 325 mg of aspirin.
   • Convert this mass to grams: ( 325 , \text{mg} = 0.325 , \text{g} ).

2. Find the molar mass of aspirin (C(_9)H(_8)O(_4)):

   • Carbon ©: ( 12.01 , \text{g/mol} \times 9 = 108.09 , \text{g/mol} )
   • Hydrogen (H): ( 1.01 , \text{g/mol} \times 8 = 8.08 , \text{g/mol} )
   • Oxygen (O): ( 16.00 , \text{g/mol} \times 4 = 64.00 , \text{g/mol} )
   • Total molar mass: ( 108.09 + 8.08 + 64.00 = 180.17 , \text{g/mol} )

3. Calculate the number of moles:

   • Using the formula:
     [ \text{moles} = \frac{0.325 , \text{g}}{180.17 , \text{g/mol}} \approx 0.0018 , \text{mol} ]

So, there are approximately 0.0018 moles of aspirin in the tablet.

Practical Application

Knowing the number of moles of aspirin in a tablet has several practical applications:

1. Dosage Accuracy: Ensuring the correct dosage is crucial for the effectiveness and safety of the medication. By knowing the exact number of moles, pharmacists and healthcare providers can accurately prescribe the right amount to achieve the desired therapeutic effect without causing harm.

2. Chemical Reactions in the Body: Aspirin (acetylsalicylic acid) undergoes hydrolysis in the body to produce salicylic acid and acetic acid. Knowing the moles helps in understanding the extent of this reaction and its impact on the body, such as its anti-inflammatory and pain-relieving effects.

3. Quality Control: Manufacturers use this information to ensure each tablet contains the correct amount of active ingredient, maintaining consistency and efficacy across batches.

These applications highlight the importance of precise measurements in both medical and pharmaceutical contexts.

Calculating Moles of Aspirin

To calculate the number of moles of aspirin in a tablet, use the formula: moles = mass (g) / molar mass (g/mol).

First, determine the mass of aspirin in the tablet and convert it to grams if necessary. Then, find the molar mass of aspirin by summing the atomic masses of its constituent elements: carbon, hydrogen, and oxygen.

Finally, divide the mass of aspirin by its molar mass to obtain the number of moles.

The Importance of Knowing Moles of Aspirin

Knowing the number of moles of aspirin in a tablet is crucial for various applications. It ensures dosage accuracy, allowing pharmacists and healthcare providers to prescribe the correct amount without causing harm.

Additionally, understanding the chemical reactions that occur in the body when taking aspirin helps in grasping its therapeutic effects and potential side effects.

Furthermore, manufacturers use this information to maintain consistency and efficacy across batches, ensuring quality control.