Question

O 4/30/2016 11:55 PM A 33.3/100 Gradebook Print Calculator Periodic Table Question 5 of 6 Map pling Consider the following fusion reaction. Identify the missing product of the reaction by replacing the question marks in the box below. Tip: If you need to clear your work and reset the Li question marks, click the icon that looks like two red arrows in the menu below the box, How much energy, in megaelectronvolts (MeV), is released in this reaction? Number AE MeV O Previous ® Give Up & View Solution Check Answer Next H Ext Hint

Answer 1

₁²H + ₃⁶Li ---> ₃⁷Li + ¹₁H

Total mass number A,

RHS=2+6=8

Total atomic number

RHS=1+3=4

So,

That unknown element have the mass number of 7 and atomic number of 3.

Hence, ₃⁷Li is the unknown element.

Sum of the masses in RHS of the reaction,

The exact mass of ₁²H = 2.01410 a.m.u.

₃Li⁶ =6.015123 a.m.u.

Total = 8.029223 a.m.u.

LHS

The exact mass of ₃Li⁷ isotope = 7.01601 a.m.u.

₁H¹ = 1.00738 a.m.u.

Total = 8.02384 a.m.u.

ΔM = Sum of the masses of products – Sum of the masses of reactants

= 8.02384 -  8.029223

= - 0.005383 a.m.u.

As there is decrease of mass, hence energy is being released.

The value of Q will be therefore Positive i.e.
Q = +0.005383 a.m.u. X 931.5 MeV/a.m.u = +5.011573 MeV
Hence the above reaction is exoergic.