Question

Identify if the two nuclear reactions mentioned below are endothermic or exothermic. Show your calculations.

\(^1_1p+^7_3Li \rightarrow 2(^4_2 He)\)

\(^7_3 Li + ^4_2 He \rightarrow \,^1_0 n+ ^{10}_5 B\)

Use the information below to answer the question:

\(^1_1 p =1.00728\,amu\)

\(^7_3 Li =7.0160\,amu\)

\(^4_2 He=4.0026\,amu\)

\(^1_0n=1.0087\,amu\)

\(^{10}_5B=10.01294\)

Answer 1

For the first reaction 

mass of reactants = 1.00728 + 7.0160 = 8.12328 amu 

mass of products = 2 × 4.0026 = 8.0052 

mass of reactants > mass of products 

Hence, the reaction is exothermic.

For the second reaction 

mass of reactants = 7.0160 + 4.0026 = 11.0186 amu

mass of products = 1.0087 + 10.1294 = 11.1381 

mass of reactants < mass of products

Hence, the reaction is endothermic.