Question

The value of Avogadro number is
(A) \[6.25\times {{10}^{18}}\]
(B) \[6.022\times {{10}^{23}}\]
(C) 96500
(D) \[3.12\times {{10}^{18}}\]

Answer 1

Hint: We know that Avogadro number has a numerical value. And we use this number for calculating the number of moles or molecules.

Step by step solution:
Avogadro's number: The number of particles in a unit known as a mole. This was not discovered by Amadeo Avogadro (1776-1856). In 1865 Loschmidt used kinetic molecular theory to estimate the number of particles in one cubic centimeter of gas at standard conditions.
Avogadro's number is the number of elementary entities (that is, atoms, electrons, ions, molecules) that exist in a mole of any substance. And mol is the unit which allows to measure and express a certain amount of substance.
This is the unit that chemists use to make known the weight of each atom, a figure that equals a very large number of particles. A "mol" equals the number of atoms in twelve grams of pure carbon-12.

The equation would be the following:
1 mole = \[6.022045\times {{10}^{23}}\]
1 mole = \[6.022045\times {{10}^{23}}\] particles.
This amount is usually rounded down to\[6.022\times {{10}^{23}}\]. And it is denoted by ‘N’.
The utility of the Avogadro constant lies in the need to count particles or microscopic entities from macroscopic measurements (such as mass).
So, the correct answer is option “B”.

Note: With Avogadro's number, we can discuss and compare very large numbers, which is useful because substances in everyday quantities contain very large numbers of atoms and molecules.