Lavoisier’s law of mass conservation:
The total mass of the substances involved in chemical transformation remains constant and therefore the sum of the masses of the reactants must be equal to the sum of the masses of the reaction products.
From a balanced chemical equation can be calculated:
- Amount of reagent is needed to react with a given amount of another.
- Amount or reagent required to obtain a given amount of product.
- Amount of product obtained from a certain amount of reagent.
Processes to follow in chemical calculations:
1º Formulate and adjust the corresponding chemical equation.
2º Set the ratio between data and unknowns.
Stoichiometric calculations using conversion factors:
- Conversion grams in moles.
- Multiply by the equivalence link between substances.
- Conversion moles in grams, or the equivalent in liters, if it is a gaseous substance.
In adjusted ionic equations the both laws of conservation of mass and electric charge must be accomplished.
You can download the App BioProfe READER to practice this theory with self-corrected exercises.