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

Explanation

Average molar mass of oxygen `=((35.96755 xx 0.337) + (37.96272 xx 0.063) + (39.9624 xx 99.600))/(0.337 + 0.063 + 99.600)`
`=39.948 g mol^(-1)`