Law of Conservation of Mass
States that mass can neither be created nor destroyed in a chemical reaction, meaning the total mass of reactants equals the total mass of products.
What is Law of Conservation of Mass?
A fundamental principle stating that the total mass of reactants in a chemical reaction must equal the total mass of products formed, as matter cannot be created or destroyed.
Key formula / rule: Conservation of Mass
Key points
- Understand the principle of mass conservation in chemical reactions.
- Apply the law to predict the mass of products or reactants.
- Recognize its significance in chemical calculations and balancing equations.
Common exam trap
Assuming mass can be lost or gained due to gaseous reactants or products escaping or entering the system (if not closed).
Definitions
- Term
Law of Conservation of Mass
- Meaning
A fundamental principle stating that the total mass of reactants in a chemical reaction must equal the total mass of products formed, as matter cannot be created or destroyed.
- Term
Closed System
- Meaning
A system in which no matter enters or leaves, allowing for accurate observation of mass conservation during reactions.
Learning objectives
Understand the principle of mass conservation in chemical reactions.
Apply the law to predict the mass of products or reactants.
Recognize its significance in chemical calculations and balancing equations.
Formulae
- Name
Conservation of Mass
- Note
This applies to chemical reactions occurring in a closed system.
- Expression
Total Mass of Reactants = Total Mass of Products
Prerequisites
Basic understanding of chemical reactions.
Concept of reactants and products.
Familiarity with atomic structure and elements.
Common mistakes
Assuming mass can be lost or gained due to gaseous reactants or products escaping or entering the system (if not closed).
Incorrectly calculating reactant or product masses without considering the stoichiometry.
Confusing conservation of mass with conservation of energy (though related by E=mc² at nuclear levels, not typically relevant for chemical reactions).
Keywords
Conservation of Mass
Lavoisier
Reactants
Products
Chemical Reaction
Stoichiometry
Matter
Closed System
Practice preview
According to the Law of Conservation of Mass, if 10 grams of reactant A reacts completely with 5 grams of reactant B, what will be the total mass of the products formed?…
easy
Which scientist is credited with formulating the Law of Conservation of Mass?…
easy
Consider the reaction: 2H₂ (g) + O₂ (g) → 2H₂O (l). If 4 grams of hydrogen gas react completely with oxygen gas to produce 36 grams of water, what mass of oxygen gas was consumed?…
medium