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Chem. Questions. The primary reaction inside stars changes?

Question by Lizzy B: Chem. Questions. The primary reaction inside stars changes?
Cant figure these questions out at all please help!

The primary reaction inside stars changes
A. hydrogen to helium.
B. helium to hydrogen.
C. uranium to plutonium.
D. nitrogen to carbon.

Based on its location on the periodic table, an element that is not naturally occuring is
A. terbium (Tb).
B. curium (Cm).
C. holmium (Ho).
D. lutetium (Lu).

The half-life of cobalt 60 is 5.3 years. What fraction of a sample remains after 21.2 years?
A. one half
B. one quarter
C. one eighth
D. one sixteenth

Best answer:

Answer by greendawn
1 is B (As happens in the sun)

2 is B (Cm is beyond Uranium, its atomic number is 96, so it doesn’t occur naturally)

3. is B (5.3/21.2 = 1/4)

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