Calculate the number of atoms in each of | Class 11 Chemistry Chapter Some Basic Concepts of Chemistry, Some Basic Concepts of Chemistry 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

nitish kumar
2019-09-10 08:34:55

thanks sir this question came to our first terminal exam,

Vipul
2019-08-04 16:34:28

Thanks

Anusha
2019-07-31 22:46:11

Thank u for answering in such a way that is really easy to understand.. ð

Chirantan
2019-07-14 20:55:57

Thank You Sir...

Sanchita sharma
2019-06-26 19:04:19

Thank you it is very helpful for me.

Santosh
2019-06-23 00:52:14

Thank you

Rashmi Chaudhary
2019-05-08 18:00:36

Thanks

Rashmi Chaudhary
2019-05-08 18:00:18

Thanks

Rashmi Chaudhary
2019-05-08 17:59:55

Thanks

Minakshi
2019-04-05 18:54:36

Thank you so much

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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 33: Calculate the number of atoms in each of the following (i) 52 moles of Ar ....

Calculate the number of atoms in each of | Class 11 Chemistry Chapter Some Basic Concepts of Chemistry, Some Basic Concepts of Chemistry NCERT Solutions

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