Final answer:
The mole is a fundamental unit in chemistry often referred to as the 'chemist's secret unit'. It allows chemists to work with the subatomic world with macro world units. This is possible because a mole of any substance contains Avogadro's number of individual units.
Step-by-step explanation:
The mole is often referred to as the chemists' secret unit because it allows chemists to work with the subatomic world with macro world units. This is possible because one mole of a substance contains Avogadro's number (6.022 x 1023) of individual units (such as atoms or molecules). Thus, it acts as a practical bridge between the atomic and macroscopic worlds.
For example, a mole of water molecules is 18g of water, but at the same time, it contains Avogadro's number of water molecules. Hence, using the concept of mole, chemists can count molecules in a way similar to how one can count eggs by dozens.
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