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

Electromagnetic radiation of wavelength | 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

Rahmat Fatima
2020-07-14 19:34:52

Thq a lot to give this answers

Kanchan verma
2019-11-14 14:03:57

I have problem in dealing with numerical

Varnika
2019-11-12 06:52:27

Thank

Y
2019-07-01 22:29:54

Aisha
2019-05-17 11:40:28

What about if use hydrogen instead of sodium

Priyanshi
2019-04-23 20:05:25

Tq saralstudy

Aryan
2019-03-24 15:13:14

Why cant we use -13.6Z^2

Aryan
2019-03-24 15:13:02

Why cant we use -13.6Z^2

Megha
2018-11-07 18:37:49

How it's come?

Abhishek upmanyu
2018-08-23 11:13:59

Right solution

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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 10: Electromagnetic radiation of wavelength 242 nm is just sufficient to ionise the sodium atom. Calcula....

Electromagnetic radiation of wavelength | Class 11 Chemistry Chapter Structure of Atom, Structure of Atom NCERT Solutions

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