Question

what is the atomic mass of an element , if 1.58×10^19 atoms weighs 1.05mg

Answer 1

HEY,

The concept to use here is that " Atomic mass of the element is the mass of Avagadro number of atoms"

1.58x10^19====>>>1.05x10^-3g

So just find the mass of 6x10^23 atoms.

6x10^23======>>>X

From both relation

X=1.05x10^-3gx6x10^23/1.58x10^19

==>>39.87===>>>>40