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

Calculate the molarity of a solution 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

Sameer
2019-07-02 20:02:19

Calculate the the molarity solution of methanol in 1 litre offer water in which of the mole fraction of is 0.5

Mukesh jain
2019-06-26 11:02:30

In this question water density given but still need to solve this question not have density of solution so a/c to my opinion that question fandamentically wrong. And if think water density is equal to solution density than answers will be2.01M

ISMAIL
2019-06-09 16:11:36

2.22/1.040=2.14461~2.1 Therefore,Molarity of Ethanol= 2.1M

ISMAIL
2019-06-09 16:09:14

WTF! 2.22Ã·1.040 = 2.134615~2.1M

sachin
2019-05-02 13:51:22

write answer is 2.22

Shanaya
2019-04-27 14:35:32

Volume of water i.e 1 litre is converted to 1000ml

Shanaya
2019-04-27 14:28:13

Volume of water i.e 1 litre is converted to 1000ml

Wajahat
2018-12-11 14:51:25

Why vol of water 1000 why God why

phd in chemistry
2018-11-12 21:56:10

the answer is totally wrong,it should be 2.09 M

Abhi
2018-09-15 08:44:05

Thanks

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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 29: Calculate the molarity of a solution of ethanol in water in which the mole fraction of ethanol is 0.....

Calculate the molarity of a solution of | Class 11 Chemistry Chapter Some Basic Concepts of Chemistry, Some Basic Concepts of Chemistry NCERT Solutions

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