Question

Use the data given in the following table to calculate the molar mass of naturally occurring argon isotopes:

Isotope	Isotopic molar mass	Abundance
${}^{36}Ar$	$35.96755g{mol}^{-1}$	$0.337$
${}^{38}Ar$	$37.96272g{mol}^{-1}$	$0.063$
${}^{40}Ar$	$39.9624g{mol}^{-1}$	$99.600$

Answer 1

Average atomic mass $=\frac{\text{Sum of the product of masses and natural abundances}}{100}$

The average atomic mass of argon $=\frac{35.96755\left(0.337\right)+37.96275\left(0.063\right)+39.9624\left(99.60\right)}{100}$

$=39.94$ g/mol.