•Q7 1 kg of H fused into He.  How much energy is liberated?   Use E = mc2, but must determine how much mass is converted.  We learned in class that 4.3 ´ 10-12 J released for each He produced.  He masses 6.645 ´ 10-27 kg, so we have 1.5x1026 He in a kg, each producing the above energy.  Multiply the energy per He times number of He = 1.5x1026 x 4.3 ´ 10-12 J =  6.4x1014 J