In a fission reaction of U-235, there was a release of #9.20 x 10^11#11 kJ of energy. What amount of mass in kilograms would have been lost?

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Answer 1 · 2016-09-14T07:02:27

#1.02xx10^-2*kg#

We use the famous mass energy equivalence formula, #E=mc^2#.

There were #9.20xx10^11*kJ# evolved in the fission of #""^235U#.

Thus #E=9.20xx10^11*kJ="mass"xx(3.00xx10^8m*s^-1)^2#

And #"mass"# #=# #(9.20xx10^11*kJ)/(3.00xx10^8m*s^-1)^2#

But #1J# #=# #1*kg*m^2*s^-2#

#"mass"# #=# #(9.20xx10^14*kg*cancel(m^2*s^-2))/((3.00xx10^8)^2*cancel(m^2*s^-2))#

Thus a mass of #1.02xx10^-2*kg# would have been converted.

Please review my figures. You might get a more nuanced answer in the Physics section.