According to Einsteins equation E equals mc2 how much mass in kg would have to disappear during a reaction for 9 x 1016 J of energy to be produced?

E = M c2

M = (E) / (c2)

M = (9 x 1016) / (3 x 108)2

= (9 x 1016) / (9 x 1016)

= 1 kg

Amazing. That's a lotta energy. Like 2.85 gigawatt-years, according to my Casio !