Question

The Q value of a nuclear reaction
A+b=C+d is defined by `Q=[m_A+m_b-m_C-m_d]c^2` where the masses refer to the respective nuclei. Determine form the given data the Q value of the following reactions and state whether the reactions are exothermic of endothermic.
(i) `._1H^(1)+._1H^3to ._1H^2+._1H^2`
(ii) `._6C^(12)+._6C^(12) to ._10Ne^(20)+._2He^4`
Atomic masses are given to be
`m(._1H^2)=2.014102u , m(._1H^3)=3.016049 u, m(._6C^(12))=12.000000u , m(._10Ne^(20))=19.992439u`

Answer 1

Correct Answer - (i)-4.031 MeV, Endothermic
(ii)+4.616 MeV, Exothermic
(i)Mass of LHS = 4.023874 u
Mass of RHS =4.028204 u
Q=[(Mass of LHS-Mass of RHS) u] x 931 MeV
Q=-4.031 MeV `rArr` reaction is endothermic
(ii)[12.000000+12.000000-(19.992439+4.002603)] x 931
Q=4.616 MeV
Q is positive `rArr` reaction is exothermic