Consider the following nuclear reaction that takes place in stars - VCE - SSCE Chemistry - Question 2 - 2007 - Paper 1
Question 2
Consider the following nuclear reaction that takes place in stars.
$$^8Be + ^4He \rightarrow ^{12}C$$
Which of the following statements about this change is/are co... show full transcript
Worked Solution & Example Answer:Consider the following nuclear reaction that takes place in stars - VCE - SSCE Chemistry - Question 2 - 2007 - Paper 1
Step 1
I The reaction is endothermic.
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Answer
The reaction is actually not endothermic; it is exothermic. During nuclear fusion processes in stars, lighter nuclei combine to form a heavier nucleus, releasing energy in the process.
Step 2
II The mass of the $^{12}C$ nucleus is greater than the combined masses of the reactants.
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Answer
This statement is incorrect. In nuclear reactions, the mass of the resulting nucleus is actually less than the total mass of the reactants. This mass difference is converted into energy, as indicated by Einstein's equation, E=mc2. Thus, the 12C nucleus has a mass that is less than the combined masses of the 8Be and 4He.
Step 3
Conclusion
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Answer
Given the evaluations above, the correct answer is D. neither I nor II.
