The drain cleaner, Drainex contains smal | Class 11 Chemistry Chapter States of Matter, States of Matter 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


Study Tips for Answering NCERT Questions:

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Comments

  • surya
  • 2019-11-13 18:25:19

thank u


  • Khushi
  • 2019-03-06 22:24:29

H2=22.4 how


  • Shahnawaaz
  • 2019-02-09 19:43:32

Why you convert temprature in kelvin although all the quantities are in cgs


  • Shahnawaaz
  • 2019-02-09 19:41:44

Why you take T1 273? And what is the base of it


  • Smn
  • 2018-11-24 23:12:44

Nice


  • prakash
  • 2018-09-24 11:07:02

How p1=1 and p2=1


  • Ashsha
  • 2018-08-04 13:19:27

22.4L converted to litre


  • Mohit
  • 2017-09-27 17:37:37

What is 22400 here


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 6: The drain cleaner, Drainex contains small bits of aluminum which react with caustic soda to produce ....