Question

How do you calculate atomic mass from isotopic composition?

Answer 1

You ascertain the nuclear mass of a component by taking the normal mass of the entirety of its iotas. The nuclear mass of a component is a weighted normal of the majority of the relative multitude of component's isotopes dependent on their rate plenitudes.

Complete answer:
Assume that we have 10 000 Cl atoms (we could assume any number). Then we have 7577 Cl-35 atoms and 2423 Cl-37 atoms.
Mass of 7577Cl - 35 atoms
$= 7577atoms \times \dfrac{34.969u}{ 1atom}$
$= 264960u$
Mass of 2423Cl - 37 atoms
$= 2423atoms \times \dfrac{36.959u}{ 1atom}$
$= 89566u$
Mass of 10000 atoms of Cl
$= 354526u$
Average mass of a Cl atom}
$= \dfrac{354526u} {10000 atoms} = 35.45u$

We are allowed to use only 4 significant figures in the answer because we were given only 4 significant figures for the isotope percentages.
For some random isotope, the amount of the quantities of protons and neutrons in the core is known as the mass number.
This is on the grounds that every proton and every neutron gauge one nuclear mass unit (amu). By including the quantity of protons and neutrons and duplicating by 1 amu, you can compute the mass of the molecule. All components exist as an assortment of isotopes.

Note: The word 'isotope' comes from the Greek 'isos' (signifying 'same') and 'topes' (signifying 'place') in light of the fact that the components can possess a similar put on the intermittent table while being distinctive in subatomic development.