# Q value of a reaction

#### circuit2000

Joined Jul 6, 2006
33
Do we have to use atomic rest masses or nuclear rest masses to find Q-value of a reaction? Also, Clark's table gives the atomic rest masses, isn't it?

#### recca02

Joined Apr 2, 2007
1,212
we take mass of alpha as helium mass,
mass of neutron as 1.00877 something in amu of course,
mass of proton as mass of hydrogen mass,
mass of atoms as the one given in periodic tables that wud be atomic.
thus masses of electrons cancel out( since hydrogen is taken instead of proton mass) and also other small errors due to electron binding energy ~ 13.6ev are negligible compared to Mevs.