Question

how to find the atomic mass of oxygen

Answer 1

We know the mass of 6.022×10^23 oxygen atoms which are present in 1 mole of an atom mass of 1 mole of an oxygen atom is 15.99 g/mol ≈16 g/mol

Therefore

1 mole of oxygen= 16 g

6.022×10^23 atoms of oxygen=16 g

1 atom of oxygen= 16÷6.022×10^23 g

1 atom of oxygen=2.65692461×10^-23

Thus mass of one oxygen atom is 2.65692461×10^-23.

Answer 2

Then, calculate the mass numbers. The chlorine isotope with 18 neutrons has an abundance of 0.7577 and a mass number of 35 amu. To calculate the average atomic mass, multiply the fraction by the mass number for each isotope, then add them together