Question

What is the mass of `5.32xx10^21` platinum atoms?

Answer 1

Well, what is the mass of `6.022xx10^23` `"platinum atoms?"`

Explanation:

You have no doubt twigged that here we must use molar quantities, and one mole of platinum atoms has a mass of `195.1*g`.

And so we take the product of the quotient....

`(5.32xx10^21*"platinum atoms")/(6.022xx10^23*"platinum atoms"*mol^-1)xx195.1*g*mol^-1`

`~=2*g`...