# Law of Mass Action, where does mass come from?

1. Mar 30, 2015

### rwooduk

1. The problem statement, all variables and given/known data

2. Relevant equations
I need help.

3. The attempt at a solution
Please, please, please could someone tell me where the mass m0 term comes from??? I'm at the end of a 7 hour revision session and need help.

2. Mar 30, 2015

### TSny

The $m_0$ inside the parentheses has been put in for convenience. It is accounted for in the number $4.9 \times 10^{15}$ which includes a factor of $m_0^{3/2}$.

3. Mar 31, 2015

### rwooduk

Thanks very much for that, it had me very confused.

4. Mar 31, 2015

### TSny

It appears to me that the calculations of $m^*_e$ and $m^*_h$ are off by factors of 2.

5. Apr 2, 2015

### rwooduk

Thanks. I'm not sure why he has added the term, and also he doesnt appear to have differentiated twice the energy at the beginning of the problem, he's just removed k. Very confusing answer to this question, but least I have the method now.