Answer:
3.18 x
molecules
Step-by-step explanation:
Molecular mass of KBr : 39 + 80 = 119 g/mol
Moles : Mass
1 : 119
X : 628.8
X = 628.8/119
X = 5.28 moles
One of of a substance contains 6.022 x
molecules.
Moles : Molecules
1 : 6.022 x

5.28 : X
X = 5.28 x (6.022 x
)
X = 3.18 x
molecules