What does Stoichiometry Tell us about Conservation of Matter?
This post will relate stoichiometry and the law of conservation of mass for Prelim Chemistry.
Topic: Chemical Reactions and Stoichiometry
- Relate stoichiometry to the law of conservation of mass in chemical reactions by investigating:
- Balancing chemical equations
- Solving problems regarding mass changes in chemical reactions
Stoichiometry is the branch of chemistry that deals with the quantitative relationships between the reactants and products in a chemical reaction. It allows us to predict the amount of each substance that will be consumed or produced in a reaction. This information is crucial for understanding the conservation of matter.
The Law of Conservation of Mass
The law of conservation of mass states that the total mass in an isolated system (a system whereby no energy nor matter can be exchanged with surroundings) will not change. This video will go through a little more about the law.
The conservation of matter states that matter cannot be created or destroyed, only transformed. This principle is at the core of stoichiometry, as it allows us to calculate the exact amount of each substance that will be present before and after a chemical reaction.
For example, if we know the stoichiometry of a reaction, we can determine the number of moles of each reactant that are required to produce a certain number of moles of a product. This is done by using the balanced equation of the reaction. By using the balanced equation and the molar ratios, we can determine the number of moles of each substance that will be present before and after the reaction, and thus ensure that the conservation of matter is upheld.
This video goes through the law of constant proportions which might enhance your understanding of stoichiometry.
Furthermore, stoichiometry can also be used to predict the yield of a reaction, which is the amount of product that will be formed in comparison to the amount of reactant used. This can be important in industrial settings, where large amounts of reactant are used and the yield of the product must be maximised.
In summary, stoichiometry allows us to understand the quantitative relationships between the reactants and products in a chemical reaction, which helps ensure the conservation of matter. It also helps us to predict the amount of product that will be formed and the amount of reactant that will be consumed in a reaction.
Balancing Chemical Equations
This video will go through balancing chemical equations which is important to fulfil the stoichiometric relationship between reactants and products.
 A little practical
This video shows how mass will be conserved (note that it is an open system here – a system whereby both matter and energy can be exchanged with the environment, not an isolated system).
