% Oxygen = (mass of oxygen in N2O4 / molar mass of N2O4) x 100
1. Find the molar mass of N2O4:
The molar mass of N2O4 is the sum of the atomic masses of two nitrogen atoms (N) and four oxygen atoms (O). The atomic mass of nitrogen is 14.01 g/mol, and the atomic mass of oxygen is 16.00 g/mol.
Molar mass of N2O4 = 2 × (14.01 g/mol) + 4 × (16.00 g/mol)
= 28.02 g/mol + 64.00 g/mol
= 92.02 g/mol
2. Calculate the mass of oxygen in N2O4:
There are four oxygen atoms in a molecule of N2O4. Each oxygen atom has a mass of 16.00 g/mol. Therefore, the mass of oxygen in N2O4 is:
Mass of oxygen in N2O4 = 4 × (16.00 g/mol)
= 64.00 g/mol
3. Calculate the mass percent of oxygen in N2O4:
Now we can substitute the values into the formula:
% Oxygen = (64.00 g/mol / 92.02 g/mol) x 100
= (0.695) x 100
= 69.5%
Therefore, the mass percent of oxygen in N2O4 is 69.5%.
