Calculate the molecular masses of H 2 , O 2 , Cl 2 , CO 2 , CH 4 , C 2 H 6 , C 2 H 4 , NH 3 , CH 3 OH

 

Answer

Atomic mass of H =1 u

Atomic mass of O = 16 u

Atomic mass of Cl = 35.5 u

Atomic mass of C = 12u

Atomic mass of N= 14 u

 

Molecular mass of H 2 = 2 x Atomic mass of H

                                     = 2 x 1u

                                     = 2u

 

Molecular mass of O 2 = 2 x Atomic mass of O

                                     = 2 x 16u

                                     = 32u

 

Molecular mass of Cl 2 = 2 x Atomic mass of Cl

                                     = 2 x 35.5u

                                     = 71u

 

Molecular mass of CO 2 = 1x Atomic mass of C + 2 x Atomic mass of O

                                     = 1 x 12u + 2x16u

                                     = 12u+32u

                                     = 48u

 

Molecular mass of CH 4 = 1x Atomic mass of C + 4 x Atomic mass of H

                                     = 1 x 12u + 4x1u

                                     = 12u+4u

                                     = 16u

 

Molecular mass of C 2 H 6 = 2x Atomic mass of C + 6 x Atomic mass of H

                                         = 2 x 12u + 6x1u

                                     = 24u+6u

                                     = 30u

 

Molecular mass of C 2 H 4 = 2x Atomic mass of C + 4 x Atomic mass of H

                                     = 2 x 12u + 4x1u

                                     = 24u+4u

                                     = 28u

 

Molecular mass of NH 3 = 1x Atomic mass of N + 3 x Atomic mass of H

                                     = 1 x 14u + 3x1u

                                     = 14u+3u

                                     = 17u

 

Molecular mass of CH 3 OH = 1x Atomic mass of C + 4 x Atomic mass of H + 1 x Atomic mass of O

                                     = 1 x 12u + 4x1u + 1 x 16u

                                     = 12u+4u+16u

                                     = 32u

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

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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