# How do I calculate Mole to Mole stoichiometry?

In mole-to-mole stoichiometry, there is a need to understand how to compare the relationship between two or more substances in an equation.

This enables us to calculate the amount of mole of substances required or produced

It is important to understand mole to mole relationships and calculations but I will recommend starting from mole to mole comparisons

Stoichiometry calculations is based simply on mole concept and the understanding of this concept enables us to do our calculations easily..

## Examples of Mole-to-Mole Calculations

This is one of the basic calculations you can get in the stoichiometry table.

Example 1

Calculate the number of moles of sulphur vi oxide evolved by reacting 3.5 moles sulphur iv oxide and oxygen according to this equation

2SO2 + O2====2SO3

Solution

First, compare the two substances mentioned in the equation

Secondly, compare the moles of the two substances mentioned.

Thirdly, underline the moles of the two substances mentioned

In this case, it is SO2 and SO3

2SO2 + O2====2SO3

2 moles of SO2 = 2 moles of SO3

3.5 moles of SO2 = X

X = 3.5 X 2 /2 = 3.5 moles of SO3

Therefore, 3.5 moles of sulphur vi oxide evolved

Example 2

Consider the equation;

N2 +3H2===2NH3

If 3.3 moles of Nitrogen reacted with unknown mole of hydrogen.  Calculate the number of moles of ammonia evolved.

Solution

Again, first you compare the substances involved

Secondly, compare the moles of the two substances mentioned.

Thirdly, underline the moles of the two substances mentioned

N2 +3H2===2NH3

So we have to calculate based on number of moles

1 mole of N2 = 2 moles of NH3

3.3 moles of N2= X

X= 3.3 X 2 /1

X= 6.6 moles of ammonia

Therefore 6.6 moles of ammonia evolved when 3.3 moles of nitrogen were evolved

Example 3

How many moles of Propane is needed to yield 5 moles of carbon iv oxide according to this

C3H8 + 5O2===3CO2 + 4H2O

Solution

C3H8 + 5O2===3CO2 + 4H2O

1 mole of C3H8 ==3 moles of CO2

X moles of C3H8==5 moles of CO2

X= 1 mole X 5 moles /3 moles

× = 1.667 mole of carbon iv oxide evolved

Example 4

What is the number of moles of carbon iv oxide produced when 0.65 moles of oxygen complexity burns an unknown mass of carbon.

C + O2==CO2

I will go straight to the calculations since I have laid down the principle a second time.

1 mole of O2===1 mole of CO2

0.65 mole of O2===X

X= 0.65 X 1 = 0.65 mole of CO2

So therefore 0.65 mole of carbon iv oxide evolved

Example 5

If 3.35 moles calcium carbonate decomposed completely to yield calcium oxide and carbon iv oxide, what’s the number of moles of carbon iv oxide produced?

Solution

CaCO3 ===CaO + CO2

If 1 mole of CaCO3==1 mole of CO2

3.35 moles of CaCO3 ==×

X= 3.35 x1 = 3.35 moles of CO2

So 3.35 moles of carbon iv oxide evolved

In conclusion, mole to mole stoichiometry is a basic calculation in stoichiometry based on mole concept analysis.