The isotopic masses of `._(1)^(2)He` and `_(2)^(4)He` are `2.0141` and `4.0026` amu respectively and the velocity of light in vacumm is `2.998xx10^(8) m//s`. Calculate the quantiy of energy (in `J`) liberated when two mole of `._(1)^(2)H` undergo fusion to form one mole of `._(2)^(4)He`

Explanation

`2_(1)^(2)H rarr ._(2)^(4) He + "Energy"`
Mass defect `= 2xx0.0141 - 4.0026 = 0.256` amu
`:. Delta E = Delta m xx c^(2)`
`= 0.256xx1.66057xx10^(-27) xx 6.02xx10^(23)xx (2.98xx10^(8))^(2)`
`= 2.3xx10^(12)J`