# I have a question about fusion

1. Apr 6, 2005

### bill nye scienceguy!

So here it is:

What is the energy released when one mole of deterium(?) undergoes complete fusion? Oh, here's the equation:

H + H = He

i dunno how to post but its 2,1 for both hydrogen isotopes and then 4,2 for the helium duh i know but i dont want confusion.

cheers ro><ors!

http://billnye.ytmnd.com/

2. Apr 6, 2005

### Meir Achuz

Fusion can't go that way because there is nowhere for the energy to go.
The most common fusion process is
$^2 H + ^3 H \rightarrow ^4 He + n.$
That is deutron + tritium --> helium + neutron.
If you want, I can calculate one mole of d on one mole of t.

3. Apr 6, 2005

### dextercioby

U mean 2 nuclei of deuterium can't fuse into an alpha particle...? What laws of physics forbid that?

Daniel.

4. Apr 6, 2005

### Meir Achuz

Billnye: The mass difference between d+t and He + n is 17.59 MeV.
Multiplying this by Avagadro's number (for one mole), and converting to Joules,
I get (Check my arithmetic.) 1.7 X 10^12 Joules released.
I guess that would be written as 1.7 tJ. That's more than I make in a year.

5. Apr 6, 2005

### Meir Achuz

dextercioby: You can't conserve both energy and momentum in d+d--> He.

6. Apr 7, 2005

### Astronuc

Staff Emeritus
d + d --> 3He + n + 3.25 MeV (~50%)

d + d --> t + p + 4.0 MeV (~50%)