Energy Change Nuclear Chemistry

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Homework Statement


Determine the energy change, delta E, in J when 500 g of 229/90 Th undergoes the following nuclear reaction:
229/90 Th --> 225/88 Ra + 4/2 He
The nuclear masses in amu or g/mol are: Th-229: 229.03175; Ra-225: 225.02360; He-4: 4.00260

Homework Equations


delta E = deltam(c)^2
c= 3*10^8
1 g= 6.02*10^23

The Attempt at a Solution


I know how to do a problem like this without a different mass input, but I have no idea how to incorporate the 500 grams into the solution. The answer is -1.09*10^12 J
 

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  • #2
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Homework Statement


Determine the energy change, delta E, in J when 500 g of 229/90 Th undergoes the following nuclear reaction:
229/90 Th --> 225/88 Ra + 4/2 He
The nuclear masses in amu or g/mol are: Th-229: 229.03175; Ra-225: 225.02360; He-4: 4.00260

Homework Equations


delta E = deltam(c)^2
c= 3*10^8
1 g= 6.02*10^23

The Attempt at a Solution


I know how to do a problem like this without a different mass input, but I have no idea how to incorporate the 500 grams into the solution. The answer is -1.09*10^12 J
Step at a time: how many mol?
 
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Step at a time: how many mol?
Would you do 500 g Th * 1 mol Th/229.03175 g Th = 2.183 mol Th
 
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Yes. Can you take it the rest of the way?
 
  • #5
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Yes. Can you take it the rest of the way?
Well I don't really know what to do with that number now. How do I incorporate it into the change in mass?
 
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g/mol are: Th-229: 229.03175; Ra-225: 225.02360; He-4: 4.00260
229 = 225 + 4; what is the mass defect?
 
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229 = 225 + 4; what is the mass defect?
The mass defect would be around -4, but so then how do you incorporate the 2.183 mol of Th??
 
  • #8
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The mass defect would be around -4
"WORNG!" Try again, please.
 

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