Convert into mole.

(a) 12 g of oxygen gas

(b) 20 g of water

(c) 22 g of carbon dioxide.

 

Answer

We know that,

Number of moles of a substance = Given mass of the substance / Molar mass of the substance

               

 

(a) 12 g of oxygen gas

 

Given mass of O 2 = m = 12g

Molar Mass of O 2 = M = 32g

We know that,

Number of moles of a substance = Given mass of the substance / Molar mass of the substance

= m/M

= 12g / 32g

= 6 /16  moles

                                     = ⅜ moles

 

(b) 20 g of water

 

Given mass of H 2 O = m = 20g

Molar Mass of H 2 O = M = 18g

We know that,

Number of moles of a substance = Given mass of the substance / Molar mass of the substance

= m/M

= 20g/18g

= 10/9  moles

                                 

 

(c) 22 g of carbon dioxide

 

Given mass of CO 2 = m = 22g

Molar Mass of CO 2 = M = 44g

We know that,

Number of moles of a substance = Given mass of the substance / Molar mass of the substance

= m/M

= 22g/44g

= 1/2  moles

                                     = 0.5 moles

  1. Class 9
  2. Chapter 3 Class 9 - Atoms And Molecules (Term 2)

About the Author

CA Maninder Singh's photo - Founder at Teachoo
CA Maninder Singh
CA Maninder Singh is a Chartered Accountant for the past 11 years and a teacher from the past 11 years. He teaches Science, Accounts and English at Teachoo