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

Calculate the wavelength, frequency and | Class 11 Chemistry Chapter Structure of Atom, Structure of Atom 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

Dilpreet
2019-08-27 19:42:44

Thanx for your answer . Its so easy and i was confused to see it . Thanks a lot to u

Abhishek
2019-08-07 21:18:03

I am confused in the middle

Ujjal
2019-07-29 20:06:01

ðððð

Dhanya
2019-07-17 21:40:29

Tanx i understood the question &answer

teju k b
2019-07-17 20:57:28

thnx for your ans

Omkar Chhabra
2019-06-30 16:00:47

Maza aa gya bhai padh kar

Omkar Chhabra
2019-06-30 16:00:22

Bohot sahi h bhai

Manju Shrestha
2019-06-26 06:39:27

Thank you... i have understood....

Devendra sharma
2019-06-08 08:30:11

Kuch samaj nhi aaya .plzz explain it better

Chetna
2019-06-07 16:49:06

It helped me a lot thnkio...ð

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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 7: Calculate the wavelength, frequency and wave number of a light wave whose period is 2.0 × 10&n....

Calculate the wavelength, frequency and | Class 11 Chemistry Chapter Structure of Atom, Structure of Atom NCERT Solutions

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