Energy Change Nuclear Chemistry

[NY152]

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

 

[Bystander]

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?

 

[NY152]

Step at a time: how many mol?

Would you do 500 g Th * 1 mol Th/229.03175 g Th = 2.183 mol Th

 

[Bystander]

Yes. Can you take it the rest of the way?

 

[NY152]

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?

 

[Bystander]

g/mol are: Th-229: 229.03175; Ra-225: 225.02360; He-4: 4.00260

229 = 225 + 4; what is the mass defect?

 

[NY152]

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??

 

[Bystander]

The mass defect would be around -4

"WORNG!" Try again, please.