Question

What is the mass of `6xx10^22` `"zinc atoms"`?

Answer 1

Well, we use the molar quantity, `N_A=6.022xx10^23*mol^-1`, and gets approx. a mass of `6.5*g`.

Explanation:

We know that `N_A` `"zinc atoms"`, i.e. `6.022xx10^23` individual zinc atoms, have a mass of `65.39*g` precisely. How do we know this? Well, because we has access to a Periodic Table, and this EXPLICITLY tells us the mass of a molar quantity.

And so we simply have to take the equivalent mass of zinc metal, i.e. `(6xx10^22*"zinc atoms")/(6.022xx10^23*"zinc atoms"*mol^-1)xx65.38*g*mol^-1=??g`.

Capisce? This is a very important concept to master in the study of chemistry.