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WorksheetsHalf-Lives
Total questions: 8
Worksheet time: 4mins
What is the mass of an original 5.60-gram sample of iron-53 that remains unchanged after 25.53 minutes?
0.35 g
0.70 g
1.40 g
2.80 g
Which radioisotope has the fastest rate of decay?
14C
37Ca
53Fe
42K
A radioactive isotope has a half-life of 2.5 years. Which fraction of the original mass remains unchanged after 10. years?
1/2
1/4
1/8
1/16
What is the total number of years that must pass before only 25.00 grams of an original 100.0-gram sample of C-14 remains unchanged?
2865 y
5730 y
11,460 y
17,190 y
What is the half-life of a radioisotope if 25.0 grams of an original 200.-gram sample of the isotope remains unchanged after 11.46 days?
2.87 d
3.82 d
11.46 d
34.38 d
An original sample of the radioisotope fluorine-21 had a mass of 80.0 milligrams. Only 20.0 milligrams of this original sample remain unchanged after 8.32 seconds. What is the half-life of fluorine-21?
1.04s
2.08s
4.16s
8.3s
How many days are required for 200. grams of radon-222 to decay to 50.0 grams?
1.91 days
3.82 days
7.64 days
11.5 days
What is the total number of grams of a 32-gram sample of 32P remaining after 71.5 days of decay?
1.0 g
2.0 g
8.0 g
4.0 g
