Alternative definition of the mole? [duplicate]








**This question already has an answer here**:
 
 




[Why was atomic mass scale changed from Oxygen - 16 to Carbon - 12?](/questions/23456/why-was-atomic-mass-scale-changed-from-oxygen-16-to-carbon-12)

 (1 answer)
 

Closed 6 years ago.



1 **amu** (atomic mass unit) is defined as the one twelfth of the mass of a carbon-12 atom. The **mole** is defined as the number of carbon-12 atom in 12 **g** of carbon-12. In other words, 


$$\require{cancel} 1 \textbf{ mole} = \dfrac{12 \textbf{ g}}{m(^{12}C)} = \dfrac{\cancel{12} \textbf{ g}}{\cancel{12} \textbf{ amu}} = \dfrac{\textbf{ g}}{\textbf{ amu}} $$


I believe that the 12 **g** were chosen so that the **mole** could exacly express the ratio between the **g** and **amu**. 


Consider now this alternative definition : the **amu** is defined as the exact mass of a proton and the **mole** is exact ratio between the **g** and the **amu**. Wouldn't it be simpler this way?


What are the advantages of one definition over the other? ~~Is there any reason we would want to keep the former?~~ Why scientists decided to define the mole like that and not pick a simpler definition like the one I proposed?




One of the reasons to take Carbon-12 could be that it's hard to get your hands on one mole of pure hydrogen (and to weigh it). Carbon-12 is a (room temperature) solid which is relatively easy to produce, keep pure, store and weigh.


 2