how Avogadro’s constant links relative atomic mass to the actual atomic mass
In: Chemistry
Technically, molar mass is standardized by the weight of Carbon-12, but that’s not how I learned it when it was first introduced to me in high school. I learned with a simplified explanation.
Each elements mass number is the combination of their protons and neutrons. For simplicity’s sake, we’ll say protons and neutrons have the same mass (they don’t really) and the name of that unit of mass is a Dalton.
Avagadro’s number links Daltons to grams. If you have an Avagadros number of things that individually weigh 1 Dalton, then an Avagadro pile of them (a mole of them) would weigh 1 gram.
So for an element like Lithium for example, it has 3 protons and 3 neutrons, so a single atom weighs ~6 Daltons. If you have an Avagadro’s number of them, then you have a pile of 6 grams of Lithium.
The try usefulness of this relationship shines when you have a sample of some known compound, and just by measuring the weight you will be able to determine the quantity of individual atoms/molecules.
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