PSci Unit 7- Nuclear Chemistry Review

What is the half-life of iodine-131?

• 32 days
• 8 days
• 16 days
• 24 days

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NGSS.HS-PS1-8

Which of the following statements is true?

• An unstable daughter isotope decays into a stable parent isotope.

• An unstable parent isotope decays into a stable daughter isotope.

• A stable daughter isotope decays into an unstable parent isotope.

• A stable parent isotope decays into an unstable daughter isotope.

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NGSS.HS-PS1-8

An isotope has a half life of 20 years. If it starts with a sample of 100g, how much of it will be left after 80 years?

• 25 grams

• 50 grams

• 6.25 grams

• 12 grams

After 2 half lives have passed, what percent of the parent isotope is left?

• 25%

• 50%

• 75%

• 100%

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NGSS.HS-PS1-8

After the third half-life, how much of a radioactive sample is left?

• 1/2
• 1/3
• 1/16
• 1/8

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NGSS.HS-PS1-8

Barium-122 has a half-life of 2 minutes. A fresh sample weighing 80 g was obtained. If it takes 10 minutes to set up an experiment using barium-122, how much barium-122 will be left when the experiment begins?

• 0.25g
• 2.5g
• 25g
• 80g

The half-life of strontium-90 is 25 years. How much strontium-90 will remain after 100 years if the initial amount is 4.0 g?

• 3.0g
• 0.25mg
• 0.3g
• 0.25g

Tags

NGSS.HS-PS1-8

¹⁴₆C has a half life of 5730 years, how many years would it take the 4.0 g sample to decay to 0.25 g?

• 4 years
• 5730 years
• 22,920 years
• 28,650 years

Tags

NGSS.HS-PS1-8

A 2.5 gram sample of an isotope of strontium-90 was formed in a 1960 explosion of an atomic bomb at Johnson Island in the Pacific Test Site. The half-life of strontium-90 is 28 years. In what year will only 0.625 grams of this strontium-90 remain? 

• 1988
• 2016
• 2044
• 2072

Actinium-226 has a half-life of 29 hours. If 100 mg of actinium-226 disintegrates over a period of 58 hours, how many mg of actinium-226 will remain? 

• 50 mg
• 25 mg
• 12.5 mg
• 6.25 mg