Select the commonly used units of e. electron volts kcal/mole newtons meters m/s

Assuming the E you are referring to is Internal Energy, which refers to the total amount of the kinetic and potential energies of the particles that form your system. The common units for this internal energy are kcal/mole, and kJ/mol.

Yes i think so not 100 percent sure though

The mass has escaped into a gas which you can not see so the law stays true.