Obtain a bottle of aspirin and identify the amount of active ingredient (acetylsalicylic acid, C₉H₈O₄) per tablet.
a. How many moles of aspirin are in one tablet?

Verified step by step guidance

1. Step 1: Identify the mass of acetylsalicylic acid (C9H8O4) per tablet from the label on the aspirin bottle. This value is typically given in milligrams (mg).
2. Step 2: Convert the mass of acetylsalicylic acid from milligrams to grams by dividing by 1000, since there are 1000 milligrams in a gram.
3. Step 3: Calculate the molar mass of acetylsalicylic acid (C9H8O4) by summing the atomic masses of its constituent atoms: Carbon (C), Hydrogen (H), and Oxygen (O). Use the periodic table to find the atomic masses: C = 12.01 g/mol, H = 1.008 g/mol, O = 16.00 g/mol. The molar mass is calculated as: $9\times 12.01+8\times 1.008+4\times 16.00$.
4. Step 4: Use the formula for moles: $n=\frac{\mathrm{mass}}{\mathrm{molar\; mass}}$. Divide the mass of acetylsalicylic acid (in grams) by its molar mass (calculated in Step 3).
5. Step 5: The result from Step 4 gives the number of moles of acetylsalicylic acid in one tablet.

Key Concepts

Molar Mass

Molar mass is the mass of one mole of a substance, typically expressed in grams per mole (g/mol). For acetylsalicylic acid (C9H8O4), the molar mass can be calculated by summing the atomic masses of its constituent elements: carbon (C), hydrogen (H), and oxygen (O). This value is essential for converting between grams and moles, allowing us to determine how many moles of aspirin are present in a given mass.

Moles

A mole is a unit in chemistry that represents a specific quantity of particles, typically atoms or molecules. One mole contains approximately 6.022 x 10^23 entities, known as Avogadro's number. Understanding moles is crucial for stoichiometric calculations, as it allows chemists to relate the mass of a substance to the number of particles, facilitating the determination of how many moles of aspirin are in a tablet based on its mass.

Active Ingredient

The active ingredient in a pharmaceutical product is the component responsible for its therapeutic effect. In the case of aspirin, the active ingredient is acetylsalicylic acid (C9H8O4). Knowing the amount of active ingredient per tablet is vital for dosage calculations and understanding the medication's efficacy, as it directly influences how many moles of the substance are available for biological activity.