Suppose a log's mass is 5 kg. after burning, the mass of the ash is 1 kg. explain what may have happened to the other 4 kg

I think the "missing mass" may have escaped the site of the
conflagration in the form of hot, invisible gases, and in the form
of all the tiny particles in the smoke.

Answerthe energy required is 1.60 × 10⁻¹⁸ j, to three significant figures.explanationwe define electric potential as the ratio electric potential energy to the charge,    then the following gives us the potential difference,      the formula  may be on your formula sheet.the change in electric potential energy would be the energy that would needed to move it from point a to point b. solving for that, we get    using q = 8.00  × 10⁻¹⁹ c and  δv = 2.00 v, we get    the energy required is 1.60 × 10⁻¹⁸ j, to three significant figures.

Ithink it is a. but i'm not 100 percent sure.