Why is mass in a nuclear reaction not conserved?

Question

Amelia Adams · Accepted Answer

Some mass is turned into energy, according to #E=mc^2#.

#E=mc^2# is probably the most famous equation. #E# is the energy, #m# is mass, and #c# is the constant speed of light. Einstein came up with it to show that energy and mass are proportional - one can turn into the other, and back again. Mass in nuclear reactions is not strictly conserved due to this principle of mass and energy being quite similar. We know that nuclear reactions release a lot of energy. This energy, though, is actually mass that is lost from nucleons, converted into energy, and lost as the mass defect.

Charlotte Aaron · Answer

undefined Mass is not conserved in a nuclear reaction due to the conversion of mass into energy, as described by Einstein's famous equation, E=mc^2. In nuclear reactions, such as fission or fusion, the nuclei of atoms are rearranged, leading to the release or absorption of energy. This energy corresponds to a change in mass according to Einstein's equation. Therefore, while the total energy (including both mass and energy) is conserved in a nuclear reaction, the mass alone is not conserved because some of it is converted into energy.