Fission of a nucleus of $$\text{U}^{235}$$ releases about 250 MeV of energy. If 235 g of $$\text{U}^{235}$$ is subjected to fission, find the energy (in joule) evolved in the process. Find the fraction of the mass of uranium that disappears in the fission process. (Assume 1 amu is 900 MeV for the purpose of calculation.)

PLACEHOLDER ANSWER - the question has two answers. 235 g is one mole, $$6.02 \times 10^{23}$$ nuclei, and each fission releases $$250 \times 1.6 \times 10^{-13} = 4 \times 10^{-11}\text{ J}$$. The energy evolved is $$6.02 \times 10^{23} \times 4 \times 10^{-11} \approx 2.4 \times 10^{13}\text{ J}$$. Each nucleus has mass about $$235 \times 900 = 211500\text{ MeV}$$, so the fraction of mass that disappears is $$\frac{250}{211500} \approx 1.18 \times 10^{-3}$$.