Law of conservation of mass

Definition

The law of conservation of mass states that in a closed system, mass cannot be created or destroyed during a chemical reaction. This principle implies that the total mass of reactants must equal the total mass of products, establishing a foundational concept in atomic theory and structure. It emphasizes that atoms are rearranged during reactions but remain unchanged in quantity.

5 Must Know Facts For Your Next Test

1. The law was first formulated by Antoine Lavoisier in the late 18th century and laid the groundwork for modern chemistry.
2. It applies not only to chemical reactions but also to physical processes like melting and evaporation, where mass remains constant.
3. In practical terms, this law means that if you start with 10 grams of reactants, you will end up with 10 grams of products after a reaction.
4. The law highlights the importance of accounting for all substances involved in a reaction, ensuring accurate measurements in experiments.
5. It serves as a key principle for understanding chemical equations, emphasizing the need for balance to reflect true conservation in reactions.

Review Questions

• How does the law of conservation of mass relate to the concept of balancing chemical equations?
  • The law of conservation of mass directly relates to balancing chemical equations because it requires that the number of atoms for each element remains consistent before and after a reaction. When chemists balance equations, they ensure that the total mass and number of atoms on both sides are equal. This practice not only demonstrates adherence to the conservation law but also helps in understanding how different substances interact during reactions.
• In what ways did Antoine Lavoisier's formulation of the law of conservation of mass influence modern chemistry?
  • Antoine Lavoisier's formulation established a fundamental principle that reshaped chemistry, emphasizing careful measurements and experimentation. By proving that matter is neither created nor destroyed, he set the stage for future scientific investigations and methodologies. This law led to systematic approaches in chemical analysis and the development of stoichiometry, which is essential for calculating reactants and products in reactions.
• Evaluate how the law of conservation of mass can be applied in real-world scenarios, such as environmental science or engineering.
  • In real-world applications like environmental science, the law of conservation of mass is crucial for tracking pollutants in ecosystems or designing waste management systems. For instance, when analyzing waste treatment processes, engineers must account for all inputs and outputs to ensure efficiency and safety. Understanding this law helps them predict how materials will transform or remain constant throughout processes, ultimately leading to better resource management and environmental protection strategies.

Related terms

Chemical Reaction: A process where reactants are transformed into products through the breaking and forming of chemical bonds.

Atom: The smallest unit of an element that retains the properties of that element, consisting of protons, neutrons, and electrons.

Balancing Equations: The process of ensuring that the number of atoms for each element is the same on both sides of a chemical equation to reflect the law of conservation of mass.