Question

Calculate the molecular mass of ( a) HNO₃ ( b) C₂H₆ ( Given atomic mass of ( 1)H= 1 amu ( 2) N= 14 amu ( 3) O= 16 amu ( 4)C= 12amu )

Answer 1

The molar mass of the chemical substance is equal to the sum of the atomic mass of the individual atoms.

Given

Atomic mass of H = 1u

Atomic mass of N = 14 u

Atomic mass of O = 16u

The molar mass of HNO3 is

(1 × 1) +(1 × 14) + (16×3) = 63 u.

molecular mass of C₂H₆= 2 × 12 + 6 × 1

                                     = 30 u.

Answer 2

Answer:

(a.) Molecular mass of HNO₃ is 63amu.

(b.) Molecular mass of C₂H₆ is 30amu.

Step-by-step explanation:

Given that,

Atomic mass of H = 1amu, N = 14amu, O = 16amu, C = 12amu.

(a.) HNO₃

In this molecule there are: 1 H-atom, 1 N-atom & 3 O-atoms.

So,

⇒ 1(1) + 1(14) + 3(16)

⇒ 1 + 14 + 48

⇒ 63

∴ Molecular mass of HNO₃ is 63amu.

(b.) C₂H₆

In this molecule there are: 2 C-atoms & 6 H-atoms.

So,

⇒ 2(12) + 6(1)

⇒ 24 + 6

⇒ 30amu

∴ Molecular mass of C₂H₆ is 30amu.

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