Can anyone help w/ this fission problem?

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To determine how many gallons of gasoline must be burned to match the energy released from fission of 1.87 lb of 235U, first convert 181 MeV to Joules, which is approximately 2.896×10^-11 J. Each fission reaction releases this energy per atom of 235U, and there are about 6.023×10^23 atoms in one mole of 235U, which weighs 235 grams. The total energy from fission can be calculated by multiplying the energy per fission by the number of atoms in the total mass of 235U. Finally, divide the total energy from fission by the energy released per gallon of gasoline, which is 1.91×10^8 J, to find the required gallons of gasoline.
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A gallon of gasoline releases 1.91×108 J of energy when it is burned. How many gallons of gas must be burned to release the same amount of energy as is released when 1.87 lb of 235U undergoes fission. (Assume that each fission reaction in 235U releases 181 MeV.)

I know this-

# gal of gas * energy= energy from fission

1.87 lbs= 2.478*10^27 amu

i thought that the answer could be found by converting 181 MeV to Joules, which equals 2.896*10^-11, multiplying that answer by the amus which equals 7.17*10^16, and then dividing it all by the energy of the gas. Apparently i am wrong however... any suggestions?
 
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How many amus are there for a 235U?
 
smij44 said:
A gallon of gasoline releases 1.91×108 J of energy when it is burned. How many gallons of gas must be burned to release the same amount of energy as is released when 1.87 lb of 235U undergoes fission. (Assume that each fission reaction in 235U releases 181 MeV.)

I know this-

# gal of gas * energy= energy from fission

1.87 lbs= 2.478*10^27 amu

i thought that the answer could be found by converting 181 MeV to Joules, which equals 2.896*10^-11, multiplying that answer by the amus which equals 7.17*10^16, and then dividing it all by the energy of the gas. Apparently i am wrong however... any suggestions?
You mistakenly tried calculating fission energy released per amu. In fact, 235U fission produces (approx) 181 MeV per 235U atom. Your overall method is correct. Recalculate using:
a) {Mass of 1 Mole 235U} = (235 g)
b) {Number Atoms 235U in 1 Mole 235U} = (6.023e23)


~~
 
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ahh... thank you very much good sir
 

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