Solving half-life problems without using the half-life formula
5. Open Ended
30 seconds
1 pt
The half-life of strontium-90 is 29 years. If you started with 10 grams of SR-90, how much would be left after 29 years?
6. Open Ended
30 seconds
1 pt
The half-life of radon-222 is 3.8 days. How much of a 100. g sample is left after 15.2 days?
7. Open Ended
30 seconds
1 pt
Carbon-14 has a half-life of 5,715 years. If a sample contains 70 mg originally, how much is left after 17,145 years?
8. Open Ended
30 seconds
1 pt
How much of a 500. g sample of potassium-42 is left after 62 hours? The half-life of potassium-42 is 12.4 hours.
9. Open Ended
30 seconds
1 pt
What is the half-life of a 100.0 g sample of nitrogen-16 that decays to 12.5 g of nitrogen-16. The half-life time of N-16 is 7.2s?
10. Open Ended
30 seconds
1 pt
If 100 g of gold-198 decays to 6.25 g the half-life of gold-198 is 2.7 days. How much time has passed?
11. Open Ended
30 seconds
1 pt
All isotopes of technetium are radioactive, but they have widely varying half-lives. If an 800.0 g sample of technetium-99 to 100.0 g of technetium-99 in 639,000 y, what is its half-life?
12. Open Ended
30 seconds
1 pt
A 208. g sample of sodium-24 decays, how much will remain after 60 hours? The half-life of Na-24 is 15h.
13. Open Ended
30 seconds
1 pt
If half-life of iodine-131 is 8.10 days, after 24.3 days how much of a 50.00 g sample will remain?
14. Open Ended
30 seconds
1 pt
The half-life of hafnium-156 is 0.025 s. How long will it take a 500. g sample to decay to ¼ its original mass?
15. Open Ended
30 seconds
1 pt
The half-life of cobalt-60 is 5.26 years. If 50.0 g are left after 15.78 years, how many grams were in the original sample?
16. Open Ended
30 seconds
1 pt
Daughter Isotope
17. Open Ended
30 seconds
1 pt
Parent Isotope
18. Open Ended
30 seconds
1 pt
As radioactive Parent isotope decrease, stable daughter isotope increases