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The d-and f-Block Elements
Calculate the molecular mass of the following: (i) H2O (ii) CO2 (ii...

Actinoid contraction is greater from ele | Class 12 Chemistry Chapter The d-and f-Block Elements, The d-and f-Block Elements 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

Romid Gayari
2019-11-04 07:06:26

Thanks for Ur answer in simple language....

Soumarya
2019-10-12 21:40:59

Good

VeryGood
2019-03-11 20:48:29

Alfredo

Richa
2019-03-08 13:34:51

Good

Alfred
2019-03-06 07:57:35

Very useful ð

Alfred
2019-03-06 00:04:14

Very useful ð

Ifthana
2019-03-01 16:41:02

Helpful

Adith
2019-02-27 16:07:22

Tnx

Ishvi
2019-02-18 09:46:59

Thanks .

Romid Gayari
2019-02-13 20:16:33

How sweet

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Welcome to the NCERT Solutions for Class 12 Chemistry - Chapter . This page offers a step-by-step solution to the specific question from Excercise 1 , Question 10: Actinoid contraction is greater from element to element than lanthanoid contraction. Why?....

Actinoid contraction is greater from ele | Class 12 Chemistry Chapter The d-and f-Block Elements, The d-and f-Block Elements NCERT Solutions

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