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

Pressure of 1 g of an ideal gas A at 27 | Class 11 Chemistry Chapter States of Matter, States of Matter 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

Sana
2019-10-17 20:34:13

Why it can't be just p directly proportional to molecular weight by which mw1=2mw2

Rockstar
2019-09-20 22:45:27

Greatest explanation

Samadrita
2019-06-27 21:06:26

Thank you. Really helpful ð

Lakshita joshi
2019-02-27 12:22:22

R is here universal gas constant

Lakshita joshi
2019-02-27 12:21:59

R is here universal gas constant

Niti
2018-11-08 15:30:29

Why does the volume is constant here ... it is not given in question ..????

shiva tiwari allhabadi
2018-10-30 07:16:11

W means n

shiva tiwari allhabadi
2018-10-30 07:15:55

R means 0.281 atm

shiva tiwari allhabadi
2018-10-30 07:11:34

Anita are u know the formula of mAss\molarmass =n and here n is represented by W ðð

Anita
2018-08-13 22:08:58

What is meaning of wA/mA+wB/mB in this question please answer

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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 5: Pressure of 1 g of an ideal gas A at 27 °C is found to be 2 bar. When 2 g of another ideal gas B....

Pressure of 1 g of an ideal gas A at 27 | Class 11 Chemistry Chapter States of Matter, States of Matter NCERT Solutions

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