Question

What is the mass of a single aluminum atom?

Answer 1

One mole of aluminum atoms has a mass of `26.98` grams, and contains `6.02xx10^23` atoms. Dividing `26.98/(6.02xx10^23)` yields a mass of `4.48xx10^-23` `g` for one aluminum atom.

Explanation:

A few notes:

I'm Australian, so I would normally spell it 'aluminium', but I'm 'speaking American'. ;-)

`6.02xx10^23` is 'Avogadro's number' - the number of anything in a a mole of that thing

In the division above, the molar mass is `26.98` `gmol^-1` and is divided by Avogadro's number which is expressed in `mol^-1`, leaving the answer in `g`, which is what we want.

Unlike in most other chemistry and physics, we work in grams rather than the SI unit of mass, the kilogram, when dealing with molar masses, because it is a more convenient sized unit.