Question

Calculate the molecular masses of C2​H6​, C2H4, NH3​, CH3​OH, O2.​

Answer 1

Answer :

Molecular mass is the sum of the masses of the individual atoms.

(I) C₂H₆

Mass of carbon atom = 12

Mass of C₂ = 2 × 12 = 24

Mass of Hydrogen atom = 1

Mass of H₆ = 1 × 6 = 6

Now, molecular mass of C₂H₆ is 24 + 6 = 30

Hence, the molecular mass of C₂H₆ is 30.

$\qquad$━━━━━━━━━━━━━━━━━

(II) C₂H₄

Mass of carbon atom = 12

Mass of C₂ = 2 × 12 = 24

Mass of Hydrogen atom = 1

Mass of H₄ = 1 × 4 = 4

Now, molecular mass of C₂H₄ is 24 + 4 = 28

Hence, the molecular mass of C₂H₆ is 28.

$\qquad$━━━━━━━━━━━━━━━━━

(III) NH₃

Mass of Nitrogen atom (N) = 14

Mass of Hydrogen atom = 1

Mass of H₃ = 1 × 3 = 3

Now, molecular mass of NH₃ is 14 + 3 = 17

Hence, the molecular mass of NH₃ is 17.

$\qquad$━━━━━━━━━━━━━━━━━

(IV) CH₃OH

Mass of carbon atom (C) = 12

Mass of Hydrogen atom = 1

Mass of H₃ = 1 × 3 = 3

Total mass of Hydrogen atoms in given compound = 3 + 1 = 4

Mass of Oxygen atom (O) = 16

Now, molecular mass of CH₃OH is 12 + 4 + 16 = 32

Hence, the molecular mass of CH₃OH is 32.

$\qquad$━━━━━━━━━━━━━━━━━

(V) O₂

Mass of Oxygen atom = 16

Mass of O₂ = 2 × 16 = 32

Hence, the molecular mass of O₂ is 32.

Answer 2

Explanation:

]Answer :

Molecular mass is the sum of the masses of the individual atoms.

(I) C₂H₆

Mass of carbon atom = 12

Mass of C₂ = 2 × 12 = 24

Mass of Hydrogen atom = 1

Mass of H₆ = 1 × 6 = 6

Now, molecular mass of C₂H₆ is 24 + 6 = 30

Hence, the molecular mass of C₂H₆ is 30.

\qquad ━━━━━━━━━━━━━━━━━

(II) C₂H₄

Mass of carbon atom = 12

Mass of C₂ = 2 × 12 = 24

Mass of Hydrogen atom = 1

Mass of H₄ = 1 × 4 = 4

Now, molecular mass of C₂H₄ is 24 + 4 = 28

Hence, the molecular mass of C₂H₆ is 28.

\qquad ━━━━━━━━━━━━━━━━━

(III) NH₃

Mass of Nitrogen atom (N) = 14

Mass of Hydrogen atom = 1

Mass of H₃ = 1 × 3 = 3

Now, molecular mass of NH₃ is 14 + 3 = 17

Hence, the molecular mass of NH₃ is 17.

\qquad ━━━━━━━━━━━━━━━━━

(IV) CH₃OH

Mass of carbon atom (C) = 12

Mass of Hydrogen atom = 1

Mass of H₃ = 1 × 3 = 3

Total mass of Hydrogen atoms in given compound = 3 + 1 = 4

Mass of Oxygen atom (O) = 16

Now, molecular mass of CH₃OH is 12 + 4 + 16 = 32

Hence, the molecular mass of CH₃OH is 32.

\qquad ━━━━━━━━━━━━━━━━━

(V) O₂

Mass of Oxygen atom = 16

Mass of O₂ = 2 × 16 = 32

Hence, the molecular mass of O₂ is 32.