Which contains the greatest number of moles of oxygen atoms?
(i) 1 mol of ethanol
(ii) 1 mol of formic acid
(iii) 1 mol of `H_(2)O`

Explanation

(i) 1 mol of ethanol `C_(2)H_(5)OH` (ethanol) - Molar mass = 24 + 6 + 16 = 46
46 g of ethanol contains `1xx 6.023 xx 10^(23)`
number of oxygen atoms.
(ii) 1 mol of formic acid
HCOOH (formic acid) - Molar mass = 2 + 12 +32 = 46
46 g of HCOOH contains `2xx 6.023 xx 10^(23)` number of oxygen atoms.
(iii) 1 mol of `H_(2)O`
`H_(2)O` (water) - Molar mass = 2+16=18
18 g of water contains `1 xx 6.023 x 10^(23)` number of oxygen atoms.
`:.` 1 mole of formic acid contains the greatest number of oxygen atoms.