# Q of p+p reaction.

1. Dec 20, 2007

### Ene Dene

p+p -> deutron+positron+neutrino(e)

The question is how much energy is released?

$$Q=(m_{p}+m_{p})-(m_{d}+m_{e^+}+0.26MeV)=(938+938)MeV-(938+939+0.51+0.26)MeV<0$$

So I don't understand how can energy be relesed? I found that Q for that reaction is 1.442MeV. What am I doing wrong?

2. Dec 20, 2007

### Hootenanny

Staff Emeritus
Note that md < mp + mn

3. Dec 20, 2007

### Ene Dene

What is the mass of deutron then? How can I calculate it, or where can I find that data?

4. Dec 20, 2007

### malawi_glenn

You should have data in your course book, and also in tables that you may use on exams etc. Here is some good internet rescourses:

http://nucleardata.nuclear.lu.se/database/masses/

The mass of the deutron is $$m_n + m_p - E_{Binding}$$

5. Dec 20, 2007

Thank you.