Half-Life Flashcard Spring 24

Front

What is half-life?

Back

Half-life is the time required for half of the radioactive atoms in a sample to decay.

Front

If you start with 100 grams of a substance with a half-life of 5730 years, how much will remain after one half-life?

Back

50 grams.

Front

What is the half-life of iodine-131?

Back

8 days.

Front

What percentage of a radioactive substance remains after 2 half-lives?

Back

25%.

Front

How much of a 100 gram sample of C-14 remains after 11,460 years?

Back

25 grams.

Front

If the half-life of uranium-232 is 70 years, how many half-lives are needed to reduce 8.0 g to 1.0 g?

Back

3 half-lives.

Front

What is the remaining percentage of carbon-14 after 22,800 years?

Back

6.25%.

Front

How do you calculate the remaining amount of a substance after a certain number of half-lives?

Back

Use the formula: Remaining amount = Initial amount × (1/2)^(number of half-lives).

Front

What happens to the amount of a radioactive isotope over time?

Back

It decreases exponentially as it undergoes decay.

Front

What is the significance of half-life in radioactive dating?

Back

Half-life helps determine the age of artifacts and fossils by measuring the remaining radioactive isotopes.