In: Chemistry
Complete each of the following nuclear reactions and calculate the energy change (in units J/mol of reactant) associated with each one. (Al-27 = 26.981538 amu, He-4=4.002603 amu, P-30=29.981801, W-179=178.94707, Ta- 179=178.94593)
(for below x / y , x = mass number while y = atomic number)
a. 27 / 13 Al + 4 / 2 He → 30 / 15 P + ______
b. 179 / 74 W + ______ →179 / 73 Ta
(a) 27 / 13 Al + 4 / 2 He
30
/ 15 P + 1 / 0 n
Mass of product = 29.981801 + 1.00867 = 30.990471 amu
Mass of reactants = 26.981538 + 4.002603 = 30.984141 amu
Change in mass for the reaction (mass of products - mass of reactants) =
m = 30.990471 -
30.984141
= 0.00633 amu
Energy =
m*
c2
= (0.00633 amu) (1.6606 x 10-27 kg/amu)(2.9979 x 108 m/s)2
= 0.0944 x 10-11 J
= 9.44 x 10-13 J
Energy per mole of reactant = 9.44 x 10-13 J / (6.023 x 1023 atoms/mol)
= 1.56 x 1010 J/mol
(b). 179 / 74 W + 0 / 1 e
179 / 73 Ta
Mass of product =178.94593 amu
Mass of reactants = 178.94707 + 0.00055 = 178.94762 amu
Change in mass for the reaction (mass of products - mass of reactants) =
m = 178.94593 -
178.94762
= - 0.00169 amu
Energy =
m*
c2
= ( - 0.00169 amu) (1.6606 x 10-27 kg/amu)(2.9979 x 108 m/s)2
= 0.0252 x 10-11 J
= 2.52 x 10-13 J
Energy per mole of reactant = 2.52 x 10-13 J / (6.023 x 1023 atoms/mol)
= 4.18 x 109 J/mol