Consider a neutral metal sphere on an insulating stand. If the sphere is charged to –79.5 nC by adding electrons, how much did the mass of the metal sphere change?

Calculate the answer in kg and make sure to include the unit. Report your final answer with three significant figures and use scientific notation, i.e. 352 000 000 would be 3.52E8 (or 3.52x10⁸).

show your work.