Answer to Question #324654 in Inorganic Chemistry for Emily

Question

How do we calculate the mass of 300 atoms of Iron(Fe)

Answer 1

Explanation:

You can get to the answer in two steps:

1)calculate: 300 atoms =

x

mol ?

2)using Avogadro's constant.

calculate:

x

mol =

?

grams,

using the atomic mass of Iron.

Step 1

Avogadro's constant says that

1

mole of any atom contains

6.022

⋅

10

23

atoms. In this case you

atoms:

300

atoms

6.022

⋅

10

23

atoms

mol

=

4.98

⋅

10

−

22

m

o

l

Step 2

The atomic mass of iron (Fe) will give you the weight of one mole of this molecule:

1

mol =

55.845

gram:

55.845

g

mol

⋅

4.98

⋅

10

−

22

mol

=

2.78

⋅

10

−

20

g

So the 300 iron atoms weigh

2.78

⋅

10

−

20

gram.