The Q value of a nuclear reaction `A + b to 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 from the given data the Q-value of the following reactions and state whether the reactions are exothermic or endothermic.
(i) `""_(1)^(1)H + ""_(1)^(3)H to _(1)^(2)H + _(1)^(2)H`
(ii) `""_(6)^(12)C + ""_(6)^(12)C to ""_(10)^(20)Ne + ""_(2)^(4)He`
Atomic masses are given to be
`m (""_(1)^(2)H) = 2.014102 u`
`m (""_(1)^(3)H) = 3.016049 u`
`m (""_(6)^(12)C ) = 12.000000 u`
`m (""_(10)^(20)Ne ) = 19.992439 u` .

Explanation

(i) Q = –4.03 MeV, endothermic
(ii) Q = 4.62 MeV, exothermic