Question

How many atoms are in exactly one mole of atom?

Answer 1

The answer to this question is dependent on the basic concept of general chemistry which involves the fact about the Avogadro law and the Avogadro constant and this fact gives the required answer.

Completes answer:
The concept of general chemistry which deals with the chapter called as some basic concepts of chemistry, tells us about the mole, molecule and atoms and their masses along with it.
We shall now see what one molecule of substance is and how can it be determined by taking one instance of a chemical reaction.
- According to the Avogadro law, mole concept that is one mole of a substance is defined as ‘the amount of a substance which contains as many elementary particles as that the number of carbon atoms present in 12 g of C – 12 isotope’.
- Avogadro proposed a law which states that ‘equal volumes of different gases measured under the same conditions of temperature and pressure contain the same number of molecules’.
This was initially not well known but 50 years later his works were known and later the Avogadro constant value was derived based on his law.
- This value was found by the experiment which gave the Avogadro number and was derived as shown below,
One atom of C-12 weighs $1.992648\times {{10}^{-23}}g$
One mole of C-12 weighs 12g.
Therefore, 12 g of C-12 contains$\dfrac{12}{1.992648\times {{10}^{-23}}}=6.0221367\times {{10}^{23}}\approx 6.022\times {{10}^{23}}$atoms.
Thus, there are $6.022\times {{10}^{23}}$atoms in exactly one mole of atom.

Note:
Note that the Avogadro number also relates the molar volume of a substance to that of the average volume which is nominally occupied by one of its particles when both are expressed in the same units of volume.