Question

Energy of 1 kg substance in?

Answer 1

You need to use the mass-energy equivalence equation, which you already know: e = mc^2, where m is the mass and c is the speed of light. Plugging in mass = 1kg and c = 3*10^8 m/s (approximately), you get

e = 1kg(3*10^8 m/s)^2 = 9*10^16 kg m^2/s^2

which is by definition equal to 9*10^16 joules