What is the molecular mass of sodium oxide #Na_2O#?
The molecular mass of sodium oxide is the sum of 2 Sodium atoms and one Oxygen atom or 62 amu
Sodium Na number 11 has 11 protons and 12 neutrons for a mass of 23 amu. Since there are two Sodiums the mass of Sodium in the molecules is 2 x 23 = 46 amu.
Oxygen Atomic number 8 has 8 protons and 8 neutrons, for a mass of 16 amu for the mass of Oxygen in the molecule is 16 amu since there is only one Oxygen atom in the molecule
Add the mass of the sodium ( 46 amu) with the mass of Oxygen (16 amu) to find the mass of the molecule
46 amu + 16 amu = 62 amu