8.98
×
N
A
cobalt atoms
Explanation:
N
A
,
Avogadro's number
specifies
6.0221
×
10
23
individual particles. It is simply another collective number like a dozen, or a score, or a gross.
N
A
has the property that
6.0221
×
10
23
individual cobalt atoms has a mass of
58.93
⋅
g
. How did I know that? Did I have it memorized?
So the quantity is
≈
54
×
10
23
cobalt atoms.
