Question

convert into moles (i)12g of oxygen gas, (ii)20g of water, (iii)22g of carbon dioxide

Answer 1

Solution :-

(i) 12 g of oxygen gas

Molar mass of oxygen (O₂) = 16 × 2 = 32 g/mole

number of moles = $\bf \frac{Given\:\:Mass}{Molar\:\:Mass} = \frac{12g}{32g/mole} = 0.375 \:\:mole$

(ii) 20 g of water

Molar mass of water (H₂O) = 2 + 16 = 18 g/mole

number of moles = $\bf \frac{Given\:\:Mass}{Molar\:\:Mass} = \frac{20g}{18g/mole} = 1.11\:\:mole$

(iii) 22 g of carbon dioxide

Molar mass of carbon dioxide (CO₂) = 12 + 32 = 44 g/mole

number of moles = $\bf \frac{Given\:\:Mass}{Molar\:\:Mass} = \frac{22g}{44g/mole} = 0.5\:\:mole$

Answer 2

Solution :-

i) 12 g of oxygen gas.

Atomic mass of oxygen gas $(O_2)$ = 32 g

Moles = Given mass / Atomic mass

= 12/32 g = 0.375 Mole

ii) 20 g of water.

Atomic mass of water $(H_2O)$ = (2 + 16) = 18 g

Moles = Given mass / Atomic mass

= 20/18 g = 1.11 Mole

iii) 22 g of carbon dioxide.

Atomic mass of carbon dioxide $(CO_2)$ = (12 + 16 + 16)= 44 g

Moles = Given mass / Atomic mass

= 22/44 g = 0.5 Mole