Question

CHEM HELP PLEASE (:

How many grams do

1.3 x 10^21 atoms of sodium weigh?

Answer 1

look at yo periodic table to find the atomic mass

it says that there is 22.98g of sodium (Na) in 1 mol of sodium

1 mol is 6.022 * 10^23 atoms

one way we can do this is ratio and proportion

`(grams_1)/(mols_1)=(grams_2)/(mols_2)`

we are solving for
`grams_2`

multiply both sides by
`mols_2`

`((grams_1)(mols_2))/(mols_1)=grams_2`

let's say
`grams_1`=22.98g and
`mols_1=6.022*10^(23)` and
`mols_2=1.3*10^(21)`

therefor

`((22.98g)(1.3&10^(21)mol))/(6.022*10^(23)mol)=grams_2`

`0.0496081g=grams_2`

so it weighs about
`5.0*10^(-2)g`