Question

Definition of molecular mass for class 9th

Answer 1

MOLECULAR MASS:
actuall no of atoms present in molecule of a compound .

Answer 2

molecule is the combination of elements, and elements have their atomic masses like-hydrogen-1 au so for molecular masses you have to add all the atomic masses which is present in a molecule.
example- H2o- atomic mass of hydrogen-1 ,atomic mass of oxygen-16
molecular masses-1*2+16
=18

hope it helps u :)