Multiple choice questions in nuclear chemistry.
1. Magnesium-28 decays via beta emission, which equation represents the balanced nuclear equation?
A.12Mg28 à -1e0 + 14Si28
B.2Mg28 à 2He4 + 10Ne28
C.12Mg28 à 1n0 + 13Al28
D.12Mg28 à -1e0 + 13Al28
E.none of the above
2. Complete the nuclear equation by 86Rn220 à 2He4 + ______ writing the symbol of the missing particle:
A.84Po216
B.84Po214
C.82Pb218
D.82Pb222
E.none of the above
3. Silicon-26 decays via positron emission, which equation represents the balanced nuclear equation?
A.14Si26 à -1e0 + 13Al26
B.14Si26 à 2He4 + 13Al26
C.14Si26 à 1e0 + 13Al28
D.14Si26 à 1e0 + 13Al26
E.none of the above
4. Complete the nuclear equation 10Ne19 à 1e0 + ______ by writing the symbol of the missing particle:
A.9F18
B.10Ne18
C.9F19
D.10Ne19
E.none of the above
5. Argon-37 decays via electron capture emission, which equation represents the balanced nuclear equation?
A.18Ar37 à -1e0 + 17Cl37
B.18Ar37 + -1e0 à 17Cl37
C.18Ar37 + 1e0 à 17Cl37
D.18Ar37 + -1e0 à 16S37
E.none of the above
6. 131I decays with a t1/2 = 8.07 hrs. If we begin with 3.0 mg, how much remains after 6 half-lives?
A.0.0469 mg
B.0.0234 mg
C.0.50 mg
D.0.25 mg
E.0.01875
7. The half-life of Pa-234 is 6.75 hr. Approximately what fraction of a sample of isotope remains after
20.25 hours?
A.¼
B.1/8
C.1/16
D.1/3
E.½
8. The half-life of Rn-222 is 3.823 day. What was the original mass of a sample of this isotope if 0.0500 g
remains after 7.646 day?
A.0.398 g
B.0.199 g
C.0.085 g
D.0.800 g
E.0.042 g
9. The half-life of Th-227 is 18.2 day. How many days are required for 0.70 of a given sample to decay?
A.4 days
B.16 days
C.32 days
D.64 days
E.128 days
10. An object taken from a cave has a carbon-14 fraction which is 0.89 of the amount in a living organism.
How old is the object? (half-life for C-14 is 5730 yr)
A.240 yrs
B.480 yrs
C.960 yrs
D.1920 years
E.3840 years