To determine the number of moles of oxygen atoms in a given amount of HNO3, we need to use the molar mass and the molecular formula of HNO3.
The molecular formula of HNO3 represents one molecule of nitric acid, which consists of one hydrogen atom (H), one nitrogen atom (N), and three oxygen atoms (O).
The molar mass of HNO3 can be calculated by adding the atomic masses of its constituent elements: H: 1.00784 g/mol N: 14.00674 g/mol O: 15.999 g/mol (for each oxygen atom)
Molar mass of HNO3 = 1.00784 g/mol + 14.00674 g/mol + (15.999 g/mol * 3) ≈ 63.0129 g/mol
Now, we can calculate the number of moles of HNO3 corresponding to 126 AMU using the molar mass:
Number of moles = Mass (in grams) / Molar mass
Mass of HNO3 = 126 AMU (atomic mass units)
To convert AMU to grams, we need to use the conversion factor: 1 AMU = 1.66054 x 10^-24 grams
Mass of HNO3 = 126 AMU * (1.66054 x 10^-24 g/AMU) ≈ 2.09138 x 10^-22 g
Number of moles = (2.09138 x 10^-22 g) / (63.0129 g/mol) ≈ 3.317 x 10^-24 mol
Since each molecule of HNO3 contains three oxygen atoms, the number of moles of oxygen atoms is three times the number of moles of HNO3:
Number of moles of O-atom = 3 * (3.317 x 10^-24 mol) ≈ 9.951 x 10^-24 mol
Therefore, the number of moles of oxygen atoms in 126 AMU of HNO3 is approximately 9.951 x 10^-24 mol.