Question

during early research in nuclear energy, why were scientists surprised that the products from splitting a uranium nucleus had less mass than the reactants? they expected that the large release of energy would cause an increase in mass. up to that time, only chemical changes were known to form less mass than they started with. all known changes always started and ended with the same amount of mass. other known nuclear changes resulted in the same mass of products as reactants.

Explanation:

In chemical and most known changes before nuclear - energy research, mass was conserved. In nuclear fission of uranium, mass loss occurred which was unexpected as scientists were used to mass - conservation principles in other changes.

Answer:

They expected that the large release of energy would cause an increase in mass.