What is the fraction of the mass of water due to neutrons?
Solution.
In water molecule , number of neutrons = [(number of neutrons in H) (number of neutrons in O)] (as number of
neutrons in H = 0)
Mass of 8 neutrons (mass of one neutron = 1.008934)
Molar mass of water
There are 8 neutrons in one atom of oxygen
Mass of 8 neutrons
Fraction of mass of water due to neutrons =