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What is a Mole?

The mole we're talking about is not a furry little critter that digs holes in your back yard.  No, it is far from it.  A mole is a number, 6.02 x 10²³ to be exact.  What's the significance of this number you may ask? Well back in the early 1900's scientists got to thinking and they decided that the Atomic Mass Unit or amu (equal to protons + nuetrons in an element) was not very practical in the laboratory.  The desired units were grams but how many atoms does it take to equal the atomic mass of an element? They knew already that the ratio between any two elements is constant.  For example 1 atom of hydrogen is 1amu and 1 atom of oxygen is 16 amus, a ratio of 1:16.  Even when the number of atoms is doubles, tripled, and so on, the ratio remains the same, 1:16.  This ment that if the masses of the elements were in ratiothen they would each contain same number of atoms.  To answer the question of how many atoms does it take to equal the atomic mass of an element, they experimented with carbon 12.  Carbon 12 has 12amus.  To determine the number of atoms in 12 grams of carbon they experimented and found that it took 6.02 x 10²³ atoms.  So the mole (abbreviated mol) is a unit of measurement and the mole of any element is defined as the number of atoms of that element equal to the number of atoms in exactly 12.0 grams of carbon-12.  But you can have a mole of anything, such as a mole of moles.  

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