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.