A nuclear fusion reaction is given by ${ }_1{H}^2{+}_1{H}^2{\to }_{2}H{e}^3{+}_0{n}^1+Q\left(energy\right)$ .
If 2 moles of deuterium are fused, then total released energy is 

2 moles of deuterium =  $2\times 6.02\times {10}^{23}$
When 2 atoms are fused – q energy is released 
$2\times 6.02\times {10}^{23}$  atoms   --- ?
Total energy released  $\frac{2\times 6.02\times {10}^{23}\times Q}{2}$
 
$=Q\times 6.02\times {10}^{23}$