Convert into mole :
(a) 12 g of oxygen gas
(b) 20 g of water
(c) 22 g of carbon dioxide.

Explanation

(a) Molar mass of oxygen `(O_(2)) = 2 xx 16` = 32 g
Given mass of oxygen = 12 g
Number of moles = `("given mass")/("molar mass")`
`=(12)/(32) = 0.375` mole
Mole of oxygen gas = 0.375 mole.
(b) Molar mass of water `(H_(2)O) = (2 xx 1) + 16` = 2 + 16 = 18 g
Given mass of water = 20 g Number of moles = `("given mass")/("molar mass")`
`=(20)/(18) ~~ 1.11` mole
Mole of water = 1.11 mole.
(c) Molar mass of carbon dioxide `(CO_(2)) = 12 + (2 xx 16)` = 12 + 32 = 44 g
Given mass of carbon dioxide = 22 g
Number of moles = `("given mass")/("molar mass")`
`=(22)/(44) = 0.5` mole
Mole of carbon dioxide = 0.5 mole.