# Mole-to-Mole Conversions

## Mole-to-mole conversions can be facilitated by using conversion factors found in the balanced equation for the reaction of interest.

#### Key Points

• The law of conservation of mass dictates that the quantity of an element does not change over the course of a reaction. Therefore, a chemical equation is balanced when all entries have equal values on both the left and right sides.

• The balanced equation for the reaction of interest contains the stoichiometric ratios of the reactants and products; these ratios can be used as conversion factors for mole-to-mole conversions.

• Stoichiometric ratios are unique for each chemical reaction.

#### Terms

• In the International System of Units, the base unit of the amount of substance; the amount of substance of a system that contains as many elementary entities as there are atoms in 0.012 kg of carbon-12. Symbol: mol. The number of atoms in a mole is known as Avogadro’s number.

#### Figures

1. ##### Mole to Mole Conversions

The mole ratio can be used as a conversion factor for mole to mole conversions.

2. ##### Stoichiometry, Moles to Moles

Shows how to determine the number of moles of reactants and products if you are given the number of moles of one of the substances in the reaction.

A chemical equation is a visual representation of a chemical reaction. A typical chemical equation follows the form $2H_{2} + O_{2} \rightarrow 2H_{2}O$

We can see the relationship between O2 and H2O: for every one mole of O2, two moles of H2O are produced. Therefore our ratio is one mole of O2 to two moles of H2O. Now, if we assume abundant hydrogen, and we have two moles of O2, then we can calculate:

$2 mol O_2 * \frac{2mol H_2O}{1 mol O_2} = 4mol H_2O$

The stoichiometric conversion factors are reaction-specific and require that the reaction be balanced. Therefore, the above steps must be followed for every single reaction you encounter.

Figure 2

#### Key Term Glossary

balanced equation
The law of conservation of mass dictates the quantity of each element does not change in a chemical reaction. Thus, each side of the chemical equation must represent the same quantity of any particular element. Similarly, the charge is conserved in a chemical reaction. Therefore, the same charge must be present on both sides of the balanced equation.
##### Appears in these related concepts:
chemical equation
a symbolic representation of a chemical reaction; reactants are represented on the left, and products on the right
##### Appears in these related concepts:
chemical reaction
A process involving the breaking or making of interatomic bonds, in which one or more substances are changed into others.
##### Appears in these related concepts:
conversion factor
A conversion factor changes something to a different version or form.
##### Appears in these related concepts:
mole
In the International System of Units, the base unit of the amount of substance; the amount of substance of a system that contains as many elementary entities as there are atoms in 0.012 kg of carbon-12. Symbol: mol. The number of atoms in a mole is known as Avogadro’s number.
##### Appears in these related concepts:
ratio
The relative magnitudes of two quantities (usually expressed as a quotient).