# Mass lost in a single fusion reaction

1. Dec 15, 2012

### eXmag

How much mass is lost in a single D + T= 4He fusion reaction? And is all of the mass lost converted to energy or just some? The mass lost can be converted to energy using e=mc2.

2. Dec 15, 2012

### SteamKing

Staff Emeritus
Obviously, all of the mass is not converted to energy, since a helium nucleus is produced.

Your reaction equation is also slightly off:

D + T = 4He + n

The energy produced is 17.6 MeV, which is equivalent to about 18.9*10-3 atomic mass units.

3. Dec 15, 2012

### eXmag

I don't think you understand what im asking. Im getting roughly around 4.7x10^-29 kg mass lost but I wanted to confirm this. You can convert that to atomic mass units if you wish but I prefer in kg. Thanks

4. Dec 15, 2012

### eXmag

which is about 0.0283u of mass lost

5. Dec 15, 2012

### Khashishi

6. Dec 15, 2012

### K^2

m(D) + m(T) - m(4He) - m(n) = mass defect and it will be equal to energy produced in the reaction. If you are getting something different, check for errors.