LIVETUTORIALS LEARNING LIBRARY
Moles, Molar Mass and Reaction Quantities
Relate a measured mass to an amount in moles and interpret balanced reaction coefficients as particle and mole ratios.
Overview
A mole is a counting unit for a specified type of entity. Molar mass links the amount of substance to mass through n = m/M, where n is amount in moles, m is mass and M is molar mass. Use compatible mass units: grams divided by grams per mole gives moles.
A balanced chemical equation conserves the number of atoms of each element. Its coefficients state relative numbers of reacting entities and therefore relative amounts in moles. They do not directly state a gram-to-gram ratio, because different substances have different molar masses.
When more than one reactant is supplied, the limiting reactant determines the maximum product amount in the ideal calculation. Compare the available moles of each reactant with the coefficient it requires. The smallest available amount per coefficient sets the reaction extent.
Keep theoretical yield separate from a measured experimental yield. These lessons calculate ideal amounts from a balanced equation and specified inputs. They do not assume that a real experiment has no losses or unwanted reactions.
References
Continue learning
- Mass-to-Mole Calculations and Limiting Reactants
Use molar mass and balanced coefficients in the correct order, and identify the reactant that limits an ideal product amount.