Question

What is the mass in grams of `5.56 X 10^22` lead atoms?

Answer 1

Well, `6.0221xx10^23` individual lead atoms have a mass of `207.2*g`.

Explanation:

So we take the quotient,

`(5.56xx10^22" atoms")/(6.022xx10^23*"atoms"*mol^-1)` `xx207.2*g*mol^-1` `=`

`"How many grams?"`

This idea of mass equivalence, of a mass representing a GIVEN number of atoms or molecules, is central to chemistry, and it is worth getting right. Using this concept, for a given reactant, we can predict the mass of products likely to be observed. Over your studies in chemistry, you will do many such problems.