Posted by Jim on Monday, April 5, 2010 at 10:22pm.
I think you have the reaction screwed up. I suspect you mean a D-T reaction
3H1 + 2H1 >> 4He2 + 1n0
add the masses on the left, you were given each. Add the masses on the right. You were given them.
Subtract the masses on the right from the masses on the left. The result is the mass deficit.
enery= massdeficit*speedlight^2
Change amu to kg.
You have a problem with the equation.
The numbers must add up on both sides and yours don't.
The lower numbers are 2 on the left and they add to 2 on the right. Good.
The top numbers don't add up. The left side is 2 and the right side is 5. (The equation is usually see is--and I'll redo the numbers so one is on the left and one is on the right--1H^2 + 1H^3 ==> 2He^4 + oN^1). When you get that straightened out, add all of the electrons, protons, and neutrons on the left (their masses) and subtract the actual mass of the products. That is the change in mass that has been converted to energy. Then delta E = delta m*c^2 and calculate energy.
The easiest fusion reaction to initiate is
2-1H + 3-1H------> 4-2He + 1-0 n
Sorry for the mistake
How would I calculate the energy released per mole of He?
If you multiply delta m (in kg) x c^2, you have the energy per molecule. A mole of He contains 6.022 x 10^23 molecules so your number x Avogadro's number gives per mole He.
Thank you very much DrBob222 and bobpursley
I have the same question. I have the answer from the book -2.820*10^-12 J/nucleus and -1.698*10^12 J/mol. I have tried to what you guys have explained, but didn´t get the answer right.
delta mass= (4.00260+1.00866)-(2.01410+3.01605)=-1.02755 amu
convert to kg:
-1.02755 amu*1.6605*10^(-27)= 1.706246*10^(-27) kg
E=m*c^2
E=1.706246*10^(-27) kg*(3.00*10^8 m/s)^2=1.53*10^-10
For the J/mol
1.706246*10^(-27) kg*6.022*10^23=0.00102 kg/mol
E=m*c^2
E=0.00102 kg/mol *(3.00*10^8m/s)^2=3.08*10^5 J/mol
What´s wrong?? :D