Are Exothermic Reactions a Violation of the Law of Conservation of Mass?

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SUMMARY

Exothermic reactions do not violate the law of conservation of mass, as this law is a practical guideline rather than an absolute principle. The energy changes in chemical reactions are negligible compared to the total mass of the reactants, making mass conservation appear valid. In contrast, nuclear reactions exhibit a more significant mass deficit, highlighting that total energy, rather than mass alone, is conserved. The discussion emphasizes that while mass and energy are equivalent, the conservation of mass is not fundamentally absolute in all contexts.

PREREQUISITES
  • Understanding of exothermic reactions and their characteristics
  • Basic knowledge of the law of conservation of mass
  • Familiarity with the concept of mass-energy equivalence
  • Awareness of nuclear reactions and their implications
NEXT STEPS
  • Research the principles of mass-energy equivalence as defined by Einstein's theory
  • Study the differences between chemical and nuclear reactions
  • Explore the implications of conservation laws in different scientific contexts
  • Examine case studies of exothermic reactions and their energy changes
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Chemistry students, educators, and professionals interested in thermodynamics and the principles of energy conservation in chemical processes.

Nikhil faraday
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Are exothermic reactions violation of law of conservation of mass , because energy and mass are equivalent? Please clarify!
 
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Conservation of mass is a rule of thumb, not a fundamental law. It works because the energy gain or loss in chemical reactions is very small compared with the total mass of the reactants. The mass deficit gets obvious in nuclear reactions. It is total energy that gets conserved.

[edit]Note: the mass-energy gain or loss in chemical reactions is very small (order parts per billion) compared with the electro-magnetic energy energy change from just rearranging the atoms.
 
Last edited:
Simon Bridge said:
Conservation of mass is a rule of thumb, not a fundamental law. It works because the energy gain or loss in chemical reactions is very small compared with the total mass of the reactants. The mass deficit gets obvious in nuclear reactions. It is total energy that gets conserved.
Thanks
 

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