How many moles of aspirin, C₉H₈O₄, are in a bottle containing 450 g by weight? (Note: The approximate atomic weights of its atoms are C = 12, H = 1, and O = 16.)

Verified step by step guidance

1. Identify the molecular formula of aspirin, which is C\_9H\_8O\_4, and note the atomic weights: C = 12, H = 1, O = 16.
2. Calculate the molar mass of aspirin by multiplying the number of each type of atom by its atomic weight and summing the results: \(\text{Molar mass} = (9 \times 12) + (8 \times 1) + (4 \times 16)\).
3. Sum the values from the previous step to find the total molar mass of one mole of aspirin in grams per mole (g/mol).
4. Use the formula to find the number of moles: \(\text{moles} = \frac{\text{mass of sample (g)}}{\text{molar mass (g/mol)}}\).
5. Substitute the given mass of aspirin (450 g) and the calculated molar mass into the formula to determine the number of moles in the bottle.

Key Concepts

Molar Mass

Molar mass is the mass of one mole of a substance, calculated by summing the atomic masses of all atoms in its molecular formula. For aspirin (C₉H₈O₄), multiply the number of each atom by its atomic weight and add them to find the molar mass in grams per mole.

Mole Concept

A mole represents 6.022 × 10²³ particles (atoms, molecules, etc.) of a substance. It links the microscopic scale of atoms to the macroscopic scale of grams, allowing conversion between mass and number of molecules using the molar mass.

Mass to Moles Conversion

To find the number of moles from a given mass, divide the mass of the substance by its molar mass. This calculation converts the weight of aspirin in grams to the amount in moles, which is essential for stoichiometric and quantitative chemical analysis.