0.650 g Au
contain
1.99
×
10
21
atoms
.
Explanation:
Calculate the moles of gold by dividing the given mass by its molar mass,
196.966569 g/mol
(atomic weight on periodic table in g/mol).
0.650
g Au
196.966569
g
mol
Au
=
0.00330 mol Au atoms
1
mol atoms
=
6.022
×
10
23
atoms
Multiply the calculated mol Au times
6.022
×
10
23
atoms
1
mol
.
0.00330
mol Au
×
6.022
×
10
23
atoms
1
mol
=
1.99
×
10
21
atoms Au
