Convert into mole.
(a) 12 g of oxygen gas
(b) 20 g of water
(c) 22 g of carbon dioxide.
Mass (in grams) = no. of moles x molecular mass (g/mol)
(a) Molar mass of O2 = 2 x 16 = 32 g/mol
Mass = no. of mole x molar mass
12 = n x 32
n = 12/3 = 3/8
n = 0.375 mole
(b) Given mass = 20 g
Molar mass of H2O = 2 x 1 + 1 x 16
= 2 + 16 = 18 g/mol
Mass = no. of mole x molar mass
20 = n x 18
n = 20/18 = 10/9
n = 1.11 mole
(c) Given mass = 22g
Molar mass of CO2 = 1 x 12 + 2 X 16
= 12 + 32 = 44 g/mol
Mass = no. of moles x molar mass
22 = n x 44
n = 22/44 = ½
n = 0.5. mole
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