Answer to Question #298232 in General Chemistry for Megan

Question

2S+3O₂→2SO₃

How many O2 molecules are needed to react with 2.15 g of S?

What is the theoretical yield of SO₃ produced by 2.15 g of S?

Answer 1

Look at the stoichiometry...S

(

s

)

+

3

2

O

2

(

g

)

→

S

O

3

(

g

)

Explanation:

The stoichiometric coefficients are in terms of moles, and certainly this REPRESENTS a numerical quantity....i.e. where N

A

=

Avogadro's number

=

6.022

×

10

23

⋅

m

o

l

−

1

.

With respect to sulfur we got a molar quantity of...

6.67

⋅

g

32.0

⋅

g

⋅

m

o

l

−

1

=

0.208

⋅

m

o

l

And therefore CLEARLY we need 0.208

⋅

m

o

l

×

3

2

=

0.313

⋅

m

o

l

 OF OXYGEN MOLECULES for stoichiometric equivalence.

0.208

⋅

m

o

l

×

3

2

×

6.022

×

10

23

⋅

m

o

l

−

1

=

1.88

×

10

23

⋅

oxygen molecules.