Multiple choice problems in nuclear chemistry.
1. Magnesium-28 decays via beta emission, which equation represents the balanced nuclear equation?
i.12Mg28 à -1e0 + 14Si28
ii.2Mg28 à 2He4 + 10Ne28
iii.12Mg28 à 1n0 + 13Al28
iv.12Mg28 à -1e0 + 13Al28
v .none of the above
2. Complete the nuclear equation by 86Rn220 à 2He4 + ______ writing the symbol of the missing particle:
i.84Po216
ii.84Po214
iii.82Pb218
iv.82Pb222
v. none of the above
3. Silicon-26 decays via positron emission, which equation represents the balanced nuclear equation?
1.14Si26 à -1e0 + 13Al26
2.14Si26 à 2He4 + 13Al26
3.14Si26 à 1e0 + 13Al28
4.14Si26 à 1e0 + 13Al26
5. 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?
1.0.0469 mg
2.0.0234 mg
3.0.50 mg
4.0.25 mg
5.0.01875
7. The half-life of Pa-234 is 6.75 hr. About 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?
1.4 days
2.16 days
3.32 days
4.64 days
5.128 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)
i.240 yrs
ii.480 yrs
iii.960 yrs
iv.1920 years
v.3840 years