What is the atomic mass of an element if 4.00 grams of it contains 2.98x1022 atoms ?

Atomic mass of the element = 80.80 amu

Explanation:

Given:

Mass of element = 4.00 g

No. of atoms =

Avogadro's no. = tex]6.02\times 10^{23}[/tex]

=

Formula for moles in the terms of mass and atomic mass

Atomic mass of the element =

Atomic mass of the element = 80.80 amu

i believe you are right for all except the 3rd ( look at sqdancefan his answer is much better)