How many molecules are present in 1.00 mg of asprin, C9H8O4?
I have posted answers to very similar questions recently. Here is an example:
http://www.jiskha.com/display.cgi?id=1259646460
don't forget to convert mg to g
To determine the number of molecules present in 1.00 mg of aspirin (C9H8O4), we need to use the concept of moles and Avogadro's number.
1. First, we need to find the molar mass of aspirin (C9H8O4).
- The molar mass of carbon (C) is approximately 12.01 g/mol.
- The molar mass of hydrogen (H) is approximately 1.01 g/mol.
- The molar mass of oxygen (O) is approximately 16.00 g/mol.
2. Calculate the molar mass of aspirin:
Molar mass of C9H8O4 = (9 * molar mass of C) + (8 * molar mass of H) + (4 * molar mass of O)
Molar mass of C9H8O4 = (9 * 12.01 g/mol) + (8 * 1.01 g/mol) + (4 * 16.00 g/mol)
Molar mass of C9H8O4 ≈ 180.16 g/mol
3. Convert the mass of aspirin from milligrams to grams since the molar mass is given in grams per mole:
1.00 mg = 0.001 g
4. Use the molar mass to convert the mass of the aspirin to moles:
Moles of aspirin = mass of aspirin / molar mass of aspirin
Moles of aspirin = 0.001 g / 180.16 g/mol
Moles of aspirin ≈ 5.55 × 10^-6 moles
5. Finally, use Avogadro's number to convert moles to the number of molecules:
Number of molecules = moles of aspirin * Avogadro's number
Number of molecules = 5.55 × 10^-6 moles * (6.022 × 10^23 molecules/mol)
Number of molecules ≈ 3.34 × 10^18 molecules
Therefore, there are approximately 3.34 × 10^18 molecules present in 1.00 mg of aspirin (C9H8O4).