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Calculate the molecular mass of the following: (i) H2O (ii) CO2 (ii...

Explain with the help of suitable exampl | Class 11 Chemistry Chapter Chemical Bonding and Molecular Structure, Chemical Bonding and Molecular Structure NCERT Solutions

Question:

Calculate the molecular mass of the following:
(i) H₂O
(ii) CO₂
(iii) CH₄

Answer:

Molecules are made up of atoms & are quite small, therefore the actual mass of a molecule cannot be detrmined.It is expressed as the relative mass.C-12 isotope is used to express the relative molecular masses of substances.Thus molecular mass of a substance may be defined as: the average relative mass of its molecule as compared to the mass of carbon atom taken as 12 amu.

(i) H₂O:

The molecular mass of water, H₂O

= (2 × Atomic mass of hydrogen) + (1 × Atomic mass of oxygen)

= [2(1.0084) + 1(16.00 u)]

= 2.016 u + 16.00 u

= 18.016

= 18.02 u

(ii) CO₂:

The molecular mass of carbon dioxide, CO₂

= (1 × Atomic mass of carbon) + (2 × Atomic mass of oxygen)

= [1(12.011 u) + 2 (16.00 u)]

= 12.011 u + 32.00 u

= 44.01 u

(iii) CH₄:

The molecular mass of methane, CH₄

= (1 × Atomic mass of carbon) + (4 × Atomic mass of hydrogen)

= [1(12.011 u) + 4 (1.008 u)]

= 12.011 u + 4.032 u

= 16.043 u

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Comments

Rihal
2019-11-05 20:35:15

Very useful

Pratik
2019-09-26 20:26:02

Thank you

Akansha bhardwaj
2019-09-21 23:16:01

Brilliant ðð

Akansha bhardwaj
2019-09-21 23:15:25

Brilliant ðð

Vunamra kharola
2018-11-02 21:46:42

Gadar bhai Gadar

raj
2018-09-26 19:01:58

The bond in NaCl is Ionic bond not covalent bond hence example is wrong answer is okay

Well wisher
2018-08-26 09:45:29

Thanks.... great answer...short,crisp and to the point

Vasu
2018-07-17 20:06:16

Good

Kishan kumar
2017-10-09 09:28:32

Very useful niceeee

Nskwow
2017-09-07 23:13:06

carrerbourgbsueilos

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Welcome to the NCERT Solutions for Class 11 Chemistry - Chapter . This page offers a step-by-step solution to the specific question from Excercise 1 , Question 18: Explain with the help of suitable example polar covalent bond.....

Explain with the help of suitable exampl | Class 11 Chemistry Chapter Chemical Bonding and Molecular Structure, Chemical Bonding and Molecular Structure NCERT Solutions

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