Q105CP - Chemistry: Molecular Nature Of Matter And Change

Question

Cosmologists modeling the origin of the elements postulate nuclides with very short half-lives. One of these nuclides, ${}^{\mathbf{8}}\mathbf{Be}\left(t_{1/2}=7\times {10}^{-17} s\right)$, plays a key role in stellar nucleosynthesis (p. 1099) because it must fuse with ${}^{\mathbf{4}}\mathbf{He}$ to form ${}^{\mathbf{12}}\mathbf{C}$ before decaying. Another explanation involves the simultaneous fusion of three ${}^{\mathbf{4}}\mathbf{He}$ nuclei to form ${}^{\mathbf{12}}\mathbf{C}$. Comment on the validity of this alternative mechanism.

Step-by-Step Solution

Answer

The bimolecular mechanism is more likely than three He nuclei fusing.

Definition of Concept

Nuclear reaction: A nuclear reaction occurs when a lighter nucleus fuses together to form new stable nuclei, or when a heavier nucleus splits into stable daughter nuclei, releasing a large amount of energy.

 

Comment on the validity of this alternative mechanism