How many moles of sodium are needed to produce 2.4 mol of sodium oxide?

Explanation:

4

N

a

+

O

2

→

2

N

a

2

O

.

By the stoichiometry of this reaction if 5 mol natrium react, then 2.5 mol

N

a

2

O

should result.

Explanation:

The molecular mass of natrium oxide is

61.98

g

⋅

m

o

l

−

1

. If

5

m

o

l

natrium react, then

5

2

m

o

l

×

61.98

g

⋅

m

o

l

−

1

=

154.95

g

natrium oxide should result.

So what have I done here? First, I had a balanced chemical equation (this is the important step; is it balanced?). Then I used the stoichiometry to get the molar quantity of product, and converted this molar quantity to mass. If this is not clear, I am willing to have another go.

considering the question as per the attachment

here we can see that the radon nuclide has 222 as the atomic mass number and 86 as the atomic number.

when it undergoes nuclear fission it gives polonium which has atomic mass number as 218 and atomic number will be 84 along with a helium nucleus which has 4 atomic mass number and 2 as its atomic number.

222 = 218 + 4 (atomic mass number)

86 = ? + 2; therefore ? = 86-2 = 84.

the atomic mass number of polonium will be 84.