If 1.0 gram of matter was converted to energy, how much energy would be formed?

To determine the equivalent energy, we use the equation of Einstein's theory of relativity which is expressed as:

Energy = mc^2    where m is the mass and c is the speed of light which is equal to 3x10^8 m/s

Substituting mass and the speed of light,
Energy = .001 kg ( 3 x 10^8 m/s )^2
Energy = 9 x10^13 J

Answer is to avoid experimental error