Ordinary Chemical Equations
* Focus: Describe changes in the arrangement of atoms and the formation or breaking of chemical bonds.
* Involve: Electrons and the outer shells of atoms.
* Changes: Changes in the *types* of molecules present (e.g., reactants becoming products).
* Mass Conservation: Mass is strictly conserved (the total mass of reactants equals the total mass of products).
* Example:
* Combustion of methane: CH₄ + 2O₂ → CO₂ + 2H₂O
* This equation shows the rearrangement of atoms to form carbon dioxide and water.
Nuclear Equations
* Focus: Describe changes in the nucleus of an atom, involving protons, neutrons, and sometimes electrons.
* Involve: Protons, neutrons, and sometimes electrons.
* Changes: Changes in the *identity* of elements (e.g., radioactive decay, nuclear fission, nuclear fusion).
* Mass Conservation: Mass is not always strictly conserved due to the conversion of mass into energy (E=mc²).
* Example:
* Alpha decay of uranium-238: ²³⁸U → ²³⁴Th + ⁴He
* This equation shows the uranium-238 nucleus decaying into thorium-234 and an alpha particle (helium nucleus).
Key Differences in a Nutshell:
* Scope: Chemical equations deal with the outer shells of atoms, while nuclear equations deal with the nucleus.
* Elements: Chemical equations may change the types of molecules but not the elements involved. Nuclear equations can change the elements themselves.
* Mass Conservation: Chemical equations strictly conserve mass. Nuclear equations may not conserve mass due to energy release.
Additional Notes:
* Conservation of Charge: Both types of equations must conserve charge (the sum of charges on the reactant side equals the sum of charges on the product side).
* Notation: Nuclear equations use superscripts for mass numbers and subscripts for atomic numbers, while chemical equations typically use symbols and numbers for the elements and their quantities.
