What is the mass percent of oxygen in C14H19NO2? Molar mass of carbon = 12.01; hydrogen = 1.01; nitrogen = 14.01; oxygen = 16.00.
The correct answer and explanation is:
To calculate the mass percent of oxygen in C14H19NO2, you first need to determine the molar mass of the compound, then calculate the contribution of oxygen to that total molar mass.
- Step 1: Calculate the molar mass of C14H19NO2.
Using the atomic masses:
- Carbon (C): 12.01 g/mol
- Hydrogen (H): 1.01 g/mol
- Nitrogen (N): 14.01 g/mol
- Oxygen (O): 16.00 g/mol
Now, let’s calculate the total molar mass:
- Carbon: 14 atoms × 12.01 g/mol = 168.14 g/mol
- Hydrogen: 19 atoms × 1.01 g/mol = 19.19 g/mol
- Nitrogen: 1 atom × 14.01 g/mol = 14.01 g/mol
- Oxygen: 2 atoms × 16.00 g/mol = 32.00 g/mol
The total molar mass of C14H19NO2:
168.14 g/mol + 19.19 g/mol + 14.01 g/mol + 32.00 g/mol = 233.34 g/mol
- Step 2: Find the mass percent of oxygen.
The mass of oxygen in the compound is 32.00 g/mol. The total molar mass of the compound is 233.34 g/mol.
The formula for mass percent is: Mass percent of oxygen=(Mass of oxygenTotal molar mass)×100\text{Mass percent of oxygen} = \left( \frac{\text{Mass of oxygen}}{\text{Total molar mass}} \right) \times 100
Substitute the values: Mass percent of oxygen=(32.00233.34)×100=13.72%\text{Mass percent of oxygen} = \left( \frac{32.00}{233.34} \right) \times 100 = 13.72\%
Conclusion: The mass percent of oxygen in C14H19NO2 is 13.72%.
This calculation involves determining the contribution of each element’s mass to the overall molar mass of the compound and then expressing the oxygen’s contribution as a percentage. This kind of calculation is essential in understanding the chemical composition and can be applied to various molecular formulas. It provides insight into the relative abundance of oxygen in the compound compared to the other elements.