how Avogadro’s constant links relative atomic mass to the actual atomic mass

Question

how Avogadro’s constant links relative atomic mass to the actual atomic mass

In: Chemistry

Answer 1

What people are missing here is that atomic mass is consistent.

Hydrogen (generally) just has one proton, helium has 2 protons and 2 neutrons, chlorine has 17 protons and 18 neutrons, etc.

Protons and neutrons basically have the same mass, so we just say they’re the same.

So, if we define a mol of hydrogen to have a mass of 1 gram, then we work backwards and find out how many atoms that is.

And the rest flows from there. An atom with 40 protons and 38 neutrons has a mass 78 times more than the hydrogen atom, so if you have that many atoms of it, it will be 78g.