 #1
LCSphysicist
 634
 153
 Homework Statement:

Find the temperature of totally ionized hydrogen plasma
of density p = 0.10 g/cm^ at which the thermal radiation pressure
is equal to the gas kinetic pressure of the particles of plasma. Take
into account that the thermal radiation pressure p = u/3, where u
is the space density of radiation energy, and at high temperatures all
substances obey the equation of state of an ideal gas.
 Relevant Equations:
 .
The image above is the solution posted by the book. I can follow the reasoning that has been used, but i have a trouble particularly at the first equation itself.
Why should $$n = 2 \rho / m_{H} $$ instead of $$n = \rho / (2m_{H})$$, since the mass os a molecule of hydrogen is two times the hydrogen/proton mass?