Half-Life

How much of the parent and daughter isotope remain after two half-lives?

• 25% parent, 75% daughter

• 25% daughter, 75% parent

• 50% daughter, 50% parent

• 12.5% parent, 87.5% daughter

Tags

NGSS.HS-PS1-8

Os-182 has a half life of 24 hours. How many grams of a 40 gram sample would have decayed after 4 half lives?

• 5.0 grams

• 96 hours

• 2 half lives

• 2.5 grams

A bone was that originally had 10 grams of Carbon 14 now has about 1.25 grams.  How many YEARS have passed? (not half lives)

• 3

• 5730

• 6000

• 17,200

As time passes, unstable parent materials decays into stable

• carbon

• daughter material

• uranium 238

• Argon

Tags

NGSS.HS-PS1-8

If the half-life of a radioactive group of atoms is 100 years, then how old is the rock if the parent decays to 25%?

• 25 years

• 200 years

• 400 years

• 800 years

Tags

NGSS.HS-PS1-8

Archeologists have found a fossil that contains 87.5 grams of nitrogen-14 and 12.5 grams of carbon-14. The half life of carbon-14 is 5730 years. How old is the fossil?

• 3 million years

• 17,190 years

• 11,460 years

• 92,000 years

Rock layers were found containing 50 kg of radioactive elements that had a half life of 2 million years. How OLD were the rock layers if scientists determined that the ORIGINAL sample had 400 kg?

• 6 million days

• 8 million years

• 4 half lives

• 6 million years

Tags

NGSS.HS-PS1-8

Radiometric dating (absolute dating) is possible because the rates of decay of radioactive isotopes _____

• change over time

• change from place to place

• are constant

• vary widely

Tags

NGSS.HS-PS1-8

Radiometric dating is possible because the rates of decay of radioactive isotopes _____.

• change over time

• change from place to place

• are constant

• vary widely

Tags

NGSS.HS-PS1-8

Some ELEMENTS can decay over time.

• True

• False

Tags

NGSS.HS-PS1-8