The atomic mass of oxygen can be calculated using the formula:
Atomic mass (O) = (Mass of isotope 1 * Abundance of isotope 1) + (Mass of isotope 2 * Abundance of isotope 2) + ...
Oxygen has three naturally occurring isotopes: oxygen-16 (mass = 15.9949 amu), oxygen-17 (mass = 16.9991 amu), and oxygen-18 (mass = 17.9992 amu).
To calculate the average atomic mass of oxygen, we need to consider the relative abundances of these isotopes. The most common isotope, oxygen-16, has an abundance of approximately 99.76%. Oxygen-17 has a very low abundance of about 0.04%, and oxygen-18 has an abundance of around 0.20%.
Using these values, we can calculate the atomic mass of oxygen as follows:
Atomic mass (O) = (15.9949 amu * 0.9976) + (16.9991 amu * 0.0004) + (17.9992 amu * 0.0020)
Atomic mass (O) ≈ 15.9994 amu
Therefore, the atomic mass of oxygen is approximately 15.9994 amu.