How big a mole really is
How much is 6.022 × 1023? Writing it out as a decimal does not help much. So try an illustration instead.
Problem
Suppose there are 1000 million children in the world. If one mole of sugar balls were shared equally among them, how many would each child get?
Solution
number of children = 1000 million = 1000 × 106 = 109
each child's share = (6.022 × 1023) ÷ 109
= 6.022 × 1014
= 602 200 000 000 000
What that tells you
Every child in the world would receive more than six hundred million million sugar balls — and only one mole was shared out. Yet weigh out water and you get a mole of its molecules from 18 g, less than a tablespoonful.
Which is exactly why the mole is needed
Particles are so small that a spoonful holds more of them than could ever be counted. What a chemist needs is a unit that turns enormous counts into ordinary numbers, and that is all the mole does: 1 in place of 6.022 × 1023.