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Grade 10 Radioactivity & Half-Life Worksheet with Answers

Grade 10 (US) · Year 11 (UK) · Class 10 (India) · Chemistry

Unit 5: Going FurtherAdvanced: Nuclear ChemistryNGSS HS-PS1-8Advanced

Calculating how much of a radioactive sample remains, and dating with half-lives. This free high school worksheet has 12 questions and a full answer key. Print it or save it as a PDF — every answer is checked by code, not guessed.

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Radioactivity & Half-Life

Grade 10 · Chemistry

Score___ / 12

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Class

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Learning goal: Advanced: Nuclear Chemistry · NGSS HS-PS1-8

Directions: Read each question carefully and write your answer on the line. Use the diagram to help you.

Example

A 400 g sample has a half-life of 20 days. How much remains after 40 days?

Answer: 100 g

RememberHalf-life

100%050%125%212.5%3half-livesAfter each half-life, half is left.amount left = start × (½)ⁿn = time ÷ half-life
  1. 1

    A sample with a half-life of 5730 years drops from 400 g to 100 g. How much time has passed?

  2. 2

    A 320 g sample has a half-life of 8 days. How much remains after 16 days?

    320 g08?16days (half-life = 8)
  3. 3

    A sample with a half-life of 30 days drops from 320 g to 160 g. How much time has passed?

  4. 4

    A sample with a half-life of 10 days drops from 320 g to 160 g. How much time has passed?

  5. 5

    A 320 g sample has a half-life of 30 days. How much remains after 30 days?

    320 g0?30days (half-life = 30)
  6. 6

    A sample with a half-life of 8 days drops from 80 g to 10 g. How much time has passed?

  7. 7

    A sample with a half-life of 5730 years drops from 640 g to 80 g. How much time has passed?

  8. 8

    A sample with a half-life of 10 days drops from 160 g to 80 g. How much time has passed?

  9. 9

    A 200 g sample has a half-life of 8 days. How much remains after 24 days?

    200 g0816?24days (half-life = 8)
  10. 10

    A 1000 g sample has a half-life of 8 days. How much remains after 8 days?

    1000 g0?8days (half-life = 8)
  11. 11

    A 400 g sample has a half-life of 20 days. How much remains after 20 days?

    400 g0?20days (half-life = 20)
  12. 12

    A 320 g sample has a half-life of 5 days. How much remains after 5 days?

    320 g0?5days (half-life = 5)

★ Challenge corner for fast finishers

Does a kilogram of feathers weigh more than a kilogram of iron?

How did I do?

Teacher's comments

Free printable worksheets with answer keys · aethelsystems.com/worksheets/chemistry/10/half_life

Answer key (click to show)
  1. 1.11,460 years
  2. 2.80 g
  3. 3.30 days
  4. 4.10 days
  5. 5.160 g
  6. 6.24 days
  7. 7.17,190 years
  8. 8.10 days
  9. 9.25 g
  10. 10.500 g
  11. 11.200 g
  12. 12.160 g
  13. ★no — they weigh the same (challenge corner)

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