3.125%
Station __:
If we start with 120 atoms of a radioactive
substance, how many will remain after 5 half
lives. Show your work.
3.75
ATOMS
Station __:
When you analyze a rock sample you find that
only 6.25% of the original Carbon-14 remains.
Knowing that Carbon-14 has a half life of 5,730
years, how old is the rock approximately? Show
your work.
22,920
YEARS
Station __:
If a sample know to be about 11,460 years old
has 400 Carbon-14 atoms, how many atoms
were in the sample when the organism died?
The half life of Carbon-14 is 5,730 years. Show
your work.
1600
ATOMS
Station __:
Sodium-24 has a half-life of 15 hours. How much
sodium-24 will remain in an 18.0 g sample after
60 hours? Show your work.
1.125
GRAMS
Station __:
• After 42 days a 2.0 g sample of Phosphorus-32
contains only .25 g of the isotope. What is the
half-life of phosphorus-32? Show your work.
14 DAYS
Station __:
Polonium-214 has a relatively short half-life of
164 seconds. How many seconds would it take
for 8.0 g of this isotope to decay to .25 g? Show
your work.
820 SECS
Station __:
How many half-lives does it take for 16 g of
Palladium-103 to decay to 1.0 g? Show your
work.
4 HALF
LIVES
Station __:
What percentage of the original sample of
Copper-66 would remain after 51 minutes if the
half-life is 5.10 minutes? Show your work.
.1 %
Station __:
In 5.49 seconds, 1.20 g of Argon-35 decays to
leave only 0.15 g. What is the half life of Argon35? Show your work.
1.83 SECS
Station __:
How much of a 30.0 gram sample of a substance
will be left after 2 hours if the half-life is 15
minutes? Show your work
.117
GRAMS
Station __:
• The half-life of Thorium-27 is 18.72 days. How
many days are require for 5.5 grams to remain
if you start with 88 grams? Show your work
74.88
DAYS
Station __:
The half-life of Cobalt-60 is 5.26 years. If 25
grams are left after 36.82 years, how many
grams were in the original sample? Show your
work
3200
GRAMS
Station __:
• The half life of Zinc-71 is 2.4 minutes. If one
had 100 g at the beginning, how many grams
would be left after 7.2 minutes. Show work.
12.5
GRAMS
Station __:
After 48 days, 2 grams of an original 128 gram
sample remain. What is the half-life of the
sample? Show work.
8 DAYS
Station __:
• The half-life of Iodine-131 is about 8 days.
What percentage of an Iodine-131 sample will
remain after 40 days? Show work.