Final answer:
To calculate the mass percent composition of N2O5, find the molar mass of the compound, divide the mass of each element in one mole by the total molar mass, and multiply by 100%. The percentage by mass for N2O5 is 25.92% N and 74.08% O.
Step-by-step explanation:
To calculate the mass percent composition of N2O5, you'll first need to determine the molar mass of the compound by summing the atomic masses of its constituent atoms. Nitrogen (N) has an atomic mass of approximately 14.01 amu, and Oxygen (O) has an atomic mass of approximately 16.00 amu. The molecular formula N2O5 indicates that there are 2 nitrogen atoms and 5 oxygen atoms in one molecule of dinitrogen pentoxide.
The molar mass of N2O5 is thus (2 × 14.01 amu) + (5 × 16.00 amu) = 28.02 amu + 80.00 amu = 108.02 amu. To find the percent composition, you divide the mass of each element in one mole of the compound by the total molar mass of the compound and multiply by 100%:
- Nitrogen: ((2 × 14.01) / 108.02) × 100% = 25.92%
- Oxygen: ((5 × 16.00) / 108.02) × 100% = 74.08%
Therefore, the percent composition by mass for N2O5 is 25.92% N and 74.08% O.