Avogadro - his number
It was long after Avogadro that the idea of a mole was introduced. Since a molecular weight in grams (mole) of any substance contains the same number of molecules, then according to Avogadro's Principle, the molar volumes of all gases should be the same. The number of molecules in one mole is now called Avogadro's number. It must be emphasised that Avogadro, of course, had no knowledge of moles, or of the number that was to bear his name. Thus the number was never actually determined by Avogadro himself.
As we all know today, Avogadro's number is very large, the presently accepted value being 6.0221367 x 1023. The size of such a number is extremely difficult to comprehend. There are many awe-inspiring illustrations to help visualize the enormous size of this number. For example:
- An Avogadro's number of standard soft drink cans would cover the surface of the earth to a depth of over 200 miles.
- If you had Avogadro's number of unpopped popcorn kernels, and spread them across the United States of America, the country would be covered in popcorn to a depth of over 9 miles.
- If we were able to count atoms at the rate of 10 million per second, it would take about 2 billion years to count the atoms in one mole.