Question

How many moles of aspirin, C₉H₈O₄, are in a 5.00×10² mg tablet?

A) 0.009 moles
B) 0.018 moles
C) 0.027 moles
D) 0.036 moles

Answer 1

To find the number of moles of aspirin in a 5.00×10² mg tablet, convert the mass to grams, then divide by the molecular mass of aspirin (180.15 g/mol). The correct answer is approximately 0.003 moles of aspirin.

Step-by-step explanation:

The subject is a chemistry calculation involving the conversion of mass to moles for aspirin, C9H8O4. To find the number of moles of aspirin in a 5.00×102 mg tablet, we first need to convert the mass from milligrams to grams, as the molar mass is given in grams per mole. We know that 1 mg is 0.001 grams.

Step 1: Convert the mass of aspirin from milligrams to grams. 5.00×102 mg is equivalent to 5.00×102 mg × 0.001 g/mg = 0.500 grams.

Step 2: Calculate the number of moles using the molecular mass of aspirin. The molecular mass of aspirin is 180.15 g/mol.
Number of moles = mass (g) / molar mass (g/mol)
Number of moles = 0.500 g / 180.15 g/mol = 0.002776 moles.

Step 3: Select the correct answer based on the calculated moles. The correct answer is option A) 0.002776 moles, which rounds to A) 0.003 moles when considering significant figures appropriate for the given options.