7.03 calculating half life worksheet/quiz

Iron-59 is used in medicine to diagnose blood circulation disorders. The half life is 44.5 days. How much of a 2.00 mg sample will be left after 133.5 days? Make sure to round to the correct number of significant figures and use units (mg).

0.25 mg___

You have a 10.0 g sample of gallium-68 . Half of it decays in 68.3 minutes. How much will be left after three half-lives? Make sure to round to the correct number of significant figures and use units (g).

_1.25 g_

How long is 5 half lives if the half life is 2.6 hours? Remember to round to the correct number of significant figures and use units (hours).

_13 hours___

What is the fraction equivalent of 7 half-lives?

__1/128___

What is the fraction equivalent of 4 half-lives?

__1/16__

You have a 10.0 g sample of gallium-68 . Half of it decays in 68.3 minutes. How much will be left after two half-lives? Make sure to round to the correct number of significant figures and use units (g).

__2.50 g___

Tritium is a radioactive form of hydrogen with a half-life of 12.3 years. If 48.0 mg is accidentally released from a nuclear power plant, how much will remain after 49.2 years? Make sure to round to the correct number of significant figures and use units (mg).

__3.00 mg___

If the half-life of Technetium-104 is 18.0 minutes, how much of a 165.0 g sample will be left after 90.0 minutes? Remember to round to the correct number of significant figures and use units (g).

__5.156 g___

Tritium is a radioactive form of hydrogen with a half-life of 12.3 years. How much of the 48.0 mg of tritium is still radioactive after 98.4 years? Make sure to round to the correct number of significant figures and use units (mg).

___0.188 mg___

What is the fraction equivalent of 8 half-lives?

___1/256___

What is the fraction equivalent of 5 half-lives?

___1/32___

Radioactivity is caused by the decay of the nucleus which occurs when unstable nuclei lose protons and neutrons. This quiz will look at the time it takes for a specific amount of radioactive material to decay, which is measured in a unit called half-life. If you are given the half-life for the decay of a particular radioisotope, then you can calculate how much of that radioisotope remains after several half-lives:fraction remaining (FR) = 1/2n where n=number of half-lives Knowing this, what is the fraction equivalent of 2 half-lives? (Your answer should be a fraction, no units necessary)

___1/4___

What is the fraction equivalent of 6 half-lives?

___1/64___

What is the fraction equivalent of 3 half-lives?

___1/8___

You have a 10.0 g sample of gallium-68 . Half of it decays in 68.3 minutes. How much will be left after one half life? Make sure to round to the correct number of significant figures and use units (g).

___5.00 g___

The remaining amount of a strontium-90 sample that has had 5 half-lives pass is 25.0g. How much was present at the beginning? Make sure to round to the correct number of significant figures and use units (g).

___800 g___

Manganese -56 has a half life of 2.6 hours. How many half lives are there in 24 hours? Remember to round to the correct number of significant figures and use units (half-lives)

___9.2 half-lives___