Question

One atom has a mass of `6.644xx10^(-23)*g`. What is the atom?

Answer 1

Well for one I think it is reasonably clear that you got the element calcium...

Explanation:

Why?

Because one atom of the stuff has a mass of `6.644xx10^-23*g`...and so ONE mole of the stuff has a mass of...

`6.644xx10^-23*gxx6.022xx10^23*mol^-1=40.0*g*mol^-1`.. and a quick glance at the Periodic Table tells us that the likely element in calcium metal..the which has a mass of `40.0*g*mol^-1`.

And so how many moles in `40*kg`?

Well....`(40xx10^3*g)/(40.0*g*mol^-1)=1000*mol`...

..and so ...

`"number of calcium atoms"=1000*molxx6.022xx10^23*mol^-1=6.022xx10^26*"calcium atoms"`