Question

How much mass change per mole of uranium-235 using the exact mass of isotopes and neutons the mass of a neutron is 1.00866 amu.
(141.9164 amu), 91Kr (90.9234 amu), and n (1.00866 amu).

find the energy released in joules/mokes

1n + 235U → 142Ba + 91Kr + 3 1n

Answer 1

1n + 235U → 142Ba + 91Kr + 3 1n

Mass of reactants

1n = 1.00866

235U = 235.043924

Total mass of reactants: 1.00866 + 235.043924 = 236.0526 amu

Mass of Products

142Ba = 141.9164

91Kr = 90.9234

Total mass of products: 141.9164 + 90.9234 + (3 x 1.00866) = 235.8658 amu

Mass Change: 236.0526 - 235.8658 = 0.1868 amu

1 amu = 1.66 x 10^-24 g

Mass change per mole: 0.1868 amu x 1.66 x 10^-24 g/amu x 6.023 x 10²³ / mole x 1000 g/ 238g/mole = 0.794 g

Amount of energy released: 0.794 g x (1amu/1.66x10^-24g) = 1.31 x 10²⁴ amu x 931 x 10⁶ eV / amu x 1.6 x 10^-19 J

Amunt of energy released: 1.95 x 10¹⁴ J

Amount of energy released per mole of U²³⁵ is 1.95 x 10¹⁴J