Convert into mole

Solution:
(a) $32 \mathrm{~g}$ of oxygen gas $=1$ mole

Then, $12 \mathrm{~g}$ of oxygen gas $=\frac{12}{32}$

$=0.375 \mathrm{~mole}$

(b) $18 \mathrm{~g}$ of water $=1 \mathrm{~mole}$

Then, $20 \mathrm{~g}$ of water $=\frac{18}{20}$

$=1.11$ moles (approx)

(c) $44 \mathrm{~g}$ of carbon dioxide $=1$ mole

Then, $22 \mathrm{~g}$ of carbon dioxide $=\frac{22}{44}$

$=0.5$ mole