Morphine has the molecular formula C17H19NO3. What is the mass percent of oxygen in morphine?

• A. 13.5%
• B. 21.2%
• C. 16.0%
• D. 9.8%

Answer: (A)

Verified step by step guidance

1. Identify the molecular formula of morphine: C17H19NO3. This tells us the number of atoms of each element in one molecule.
2. Calculate the molar mass of morphine by summing the atomic masses of all atoms: multiply the number of each type of atom by its atomic mass (C = 12.01 g/mol, H = 1.008 g/mol, N = 14.01 g/mol, O = 16.00 g/mol) and add them together using the formula: \(\text{Molar mass} = 17 \times 12.01 + 19 \times 1.008 + 1 \times 14.01 + 3 \times 16.00\).
3. Calculate the total mass of oxygen atoms in the molecule by multiplying the number of oxygen atoms by the atomic mass of oxygen: \$3 \times 16.00$ g/mol.
4. Determine the mass percent of oxygen by dividing the total mass of oxygen by the molar mass of morphine and then multiplying by 100 to convert to a percentage: \(\text{Mass \% O} = \left( \frac{3 \times 16.00}{\text{Molar mass of morphine}} \right) \times 100\).
5. Interpret the result to find the mass percent of oxygen in morphine, which corresponds to one of the given answer choices.