* Total mass: This is the fundamental principle of conservation of mass. The total mass of the reactants (starting materials) must equal the total mass of the products (what's formed). Atoms are not created or destroyed, just rearranged.
* Number of atoms: While the arrangement of atoms changes, the total number of each type of atom remains the same. This is also related to conservation of mass.
* Total energy: This is the principle of conservation of energy. Energy can be converted from one form to another (like chemical energy to heat), but it cannot be created or destroyed.
However, the following things change during a chemical reaction:
* Chemical composition: The chemical makeup of the substances changes as new compounds are formed.
* Physical properties: Properties like melting point, boiling point, color, and density might change drastically as new substances are created.
* State of matter: The physical state of the reactants and products can change (e.g., from liquid to gas).
Let me know if you'd like to explore any of these concepts further!
