Final answer:
To find the mass percent of oxygen in epinephrine, calculate the mass contribution of oxygen based on its atomic mass and frequency in the molecular formula, then divide it by the molar mass of the whole compound and multiply by 100.
Step-by-step explanation:
To calculate the mass percent of oxygen in epinephrine, first, we need the molecular formula of epinephrine, which is C9H13NO3. This formula shows that there are 9 carbons (C), 13 hydrogens (H), 1 nitrogen (N), and 3 oxygens (O). To find the mass percent of oxygen, we must:
- Determine the molar mass of each element in the compound.
- Calculate the total molar mass of the compound.
- Find the mass contributed by oxygen and divide it by the total molar mass.
- Multiply the result by 100 to obtain the percent composition.
Using the atomic masses from the periodic table (approximate atomic masses: C = 12.01, H = 1.01, N = 14.01, O = 16.00), we calculate the molar mass of epinephrine: (9 × 12.01) + (13 × 1.01) + (1 × 14.01) + (3 × 16.00). Next, we find the mass of oxygen: 3 × 16.00. Then, divide the mass of oxygen by the total molar mass of epinephrine and multiply by 100 to get the mass percent of oxygen.
The exact calculations can be performed to obtain a precise percentage, and this process can be used for other compounds to determine the mass percent of any element within them.