Discuss the shape of the following molec | 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

  • Jubin Debnat
  • 2019-10-03 19:44:33

Thank you


  • Melvin Y Sayee
  • 2019-07-14 16:28:21

merci


  • Chandan Kumar
  • 2019-03-01 21:10:22

Thank you


  • Rahul
  • 2019-02-26 09:27:24

What is the shape of XeF4


  • Rahul
  • 2019-02-26 09:25:54

XeF4. & SF6 shape


  • Raghiv
  • 2019-01-18 21:40:25

Plz explain, CH4 also


  • Anna
  • 2017-09-05 22:27:08

why CH4,NH3,H2O are not shown?


  • perveen neha
  • 2017-08-05 14:45:40

PH3 does not have trigonal bipyramidal shape rather it has trigonal pyramidal shape


  • jjjjjjjjjjiu
  • 2017-01-20 23:24:54

shape ofch4


Comment(s) on this Question

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 7: Discuss the shape of the following molecules using the VSEPR model: BeCl2, BCl3, SiCl4, AsF5, H2S....