8. how many atoms of cobalt are in a 0.39 mole sample of coc

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.

the dissolution of polymer can be thermodynamically described in 2 steps.