calculate the amount of U(wt.235) which must go nuclear fission.?

Question

to produce the same amount of energy as produced by 1 ton of coal.The heat of combustion of coal is 8x10^3cal/g.The fission of U(235) produces 200Mev energy per fission.
(1cal=4.2J; 1 ton=10^6g; Av.number=6.023x10^23;
1eV=1.602x10^-19J)

Answer 1

1) 1 ton of coal produces 10^6 x 8x10^3 cal = 3.36 x 10^10 J.

2) 1 fission produces 200 MeV = 200 x 10^6 x 1.602x10^-19J = 3.204 x 10^-11 J.

3) We therefore need 3.36 x 10^10 J/3.204 x 10^-11 J = 1.049 x 10^21 fissions, which is 1.049 x 10^21 / 6.023x10^23 = 1.741 x 10^-3 mol, which is 1.741 x 10^-3 * 235 = 0.409 gram.

Answer 2

So, calculate the amount of energy in the ton of coal and divide by the energy of a single fission. Then divide by Avagadro's number to get the moles of U235 required.