Question

Find the number of moles: (a) 12g of Oxygen Gas (b) 20g of Water (c) 22g of Carbon Dioxide —————————————————————

Answer 1

Given :

▪ Mass of oxygen gas = 12g

▪ Mass of water = 20g

▪ Mass of carbon dioxide = 22g

To Find :

➳ Number of moles of each compound$.$

Solution :

➝ No. of mole is defined as the ratio of mass of substance to the molar mass of substance$.$

➝ It has no unit. (unitless quantity)

፨ Molar mass of $\sf{O_2}$= 32g/mol

፨ Molar mass of $\sf{H_2O}$ = 18g/mol

፨ Molar mass of $\sf{CO_2}$= 22g/mol

Let's calculate ☃

(I) No. of moles of oxygen gas :

➢ n¹ = 12/32 = 0.375

(II) No. of moles of water :

➢ n² = 20/18 = 1.11

(III) No. of moles of carbon dioxide :

➢ n³ = 22/44 = 0.5