SATHEE: Some Basic Concepts of Chemistry

Some Basic Concepts of Chemistry - Result Question 3

####6. If Avogadro number $N_{A}$ , is changed from $6.022 \times 10^{23} m o l^{- 1}$ to $6.022 \times 10^{20} m o l^{- 1}$ this would change :

[2015 RS]

(a) the definition of mass in units of grams

(b) the mass of one mole of carbon

(d) the ratio of elements to each other in a compound

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Solution:

(b) If $6.022 \times 10^{23}$ changes to $6.022 \times 10^{20} / m o l$ then this would change mass of one mole of carbon.

Mass of $_{12} C$ carbon is used to define the atomic mass unit. In this system, $12 C$ is assigned a mass of exactly 12 a.m.u.

Earlier one mole was defined as the amount of substance that contains as many particles as there are atoms in exactly $12 g$ of the $_{12} C$ isotope. From November 2018, one mole is defined as exactly $6.02214076 \times 10^{23}$ constitutive particles, which may be atoms, molecules, ions or electrons.

Hence, if we change the value of NA from $6.022 \times$ $10^{23} m o l^{- 1}$ to $6.022 \times 10^{20} m o l^{- 1}$ then mass of one mole of carbon will also change.

The definition of mass is independent of Avogadro number $N_{A}$ .

(3) Molecules of water $=$ mole $\times N_{A} = 10^{- 3} N_{A}$

Some Basic Concepts of Chemistry - Result Question 3

Solution:

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Some Basic Concepts of Chemistry - Result Question 3

Solution:

Engineering Preparation

Medical Preparation

NCERT Books & Solutions

Important Resources

Other Resources

Syllabus

Test Platform

Sample Mock Test

Mentorship

NCERT Exercise Video Solution

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