Question

CHEM HELP PLEASE

How many grams do 1.3 x 10^21 atoms of sodium weigh??

Answer 1

So first we must find how many moles this amount of atoms is. We know that Avogadro's number is the amount of atoms per mole:

`(1mole)/(6.022x10^(23) atoms) *[1.3*10^(21)atoms]=2.16*10^(-3)mol`

So then we look to the periodic table to find the molar weight of sodium (Na).

Sodium's molar weight is 22.99g/mol. So let's solve for the amount of grams:

`(22.99g)/(1mol)*[2.16*10^(-3)mol]=4.97*10^(-2)g`

So now we know that the given amount of atoms weighs
`4.97*10^(-2)g`.