Question

How should the student label each circle in the diagram

Answer 1

Reaction A is chemical, Reaction B is nuclear

Step-by-step explanation:

Answer 2

The student should name the left circle "chemical reaction" and the right circle "nuclear reaction". Nuclear reaction occur in the nucleus of the involved atoms, affect the number of neutrons in these atoms, and produce a great deal more energy than chemical reactions.
Chemical reactions involve a rearrangement of the electrons in atoms, rather than changing the atoms themselves, and release a relatively small amount of energy.