Oxygen is a mixture of two isotopes 16-O and 18-O with relative abundances of 90% and 10% respectively. The relative atomic mass of oxygen is?
16.0
16.2
17.0
18.0
Correct answer is B
816O, 818O
90% 10%
R.A.M = (90)/(100) x 16 + (10)/(100) x 18 = 14.4 + 1.8 = 16.2