(i) Calculate the mass of 2.5 mole of oxygen atom.
(ii) Calculate the number of molecules in 11g of `CO_2`.

Explanation

(i) Number of moles `=("Mass")/("Atomic mass")`
`:. ` Mass = Number of moles `xx` Atomic mass
`=0.5xx16=8g`
(ii) Gram Molecular of `CO_2=44g`
Number of molecules present in 44 g of `CO_2=6.023xx10^(23)`
`:.` Number of molecules present in 11g of `CO_2=(6.023xx10^(23))/44xx11`
`=1.53xx10^(23)` molecules
(iii) Number of moles = `("Mass")/("Atomic mass")`
`81/27=3` moles